England and Wales High Court (Patents Court) Decisions

PATENTS COURT

BEFORE: MR JUSTICE NEUBERGER

BETWEEN:

Mr Mark Platts-Mills QC and Mr Michael Tappin (instructed by Messrs. Dibb Lupton Alsop) appeared as Counsel on behalf of the Plaintiff and the Defendants to Counterclaim.

Mr Alastair Wilson QC, Mr Richard Hodgson and Mr Owen Keane (instructed by Messrs. Parker & Hammond) appeared as Counsel on behalf of the 2nd to 7th Defendants.

1. This is a patent action relating to machines for extruding asphalt kerb. It arises out of a patent registered in the name of the plaintiff, Mr Willis Charlesworth, UK Patent No 2116620 ("the Charlesworth Patent"), which claims a priority date of 27th February 1982, and whose claimed inventor is the plaintiff. The action raises two main issues. The first is whether the Charlesworth Patent is valid; in this connection, it is contended by the second to seventh defendants (whom I will call "the defendants") that the invention claimed by the Charlesworth Patent was obvious in the light of two earlier patents (which I shall call "Cheney One" and "Cheney Two") respectively published in 1962 and 1967, each in the name of Mr Alwyn Cheney, and also in the light of prior use. The second main issue relates to infringement: it is whether the defendants or any of them manufactured for use, or actually used, a machine ("the defendants' machine") which infringed the Charlesworth Patent.

2. The first defendant, Relay Roads Ltd ("RR"), is in liquidation, and has taken no part in this trial. Accordingly, its counterclaim, which alleges groundless threats under Section 70 of the Patents Act 1977 and/or malicious falsehood, does not proceed and will be dismissed.

3. It is right to mention that the action first came on for trial on 17th March 1998, when the plaintiff successfully applied for an adjournment in the light of an application by the defendants to amend their Particulars of Objections and to serve an amended description of the defendants' machine. The adjourned hearing of the action began on 1st October 1998, and lasted over a total of ten days including 3rd November 1998, when I heard closing submissions.

4. The subject matter of these proceedings is machinery for laying a continuous section of road kerb. Such kerb is found primarily at the edge of the hard shoulder on major roads (including motorways), and serves to direct rainwater to drains, thereby preventing uncontrolled run-off. Such continuous kerb had been produced on site for some decades using one of two methods, namely extrusion and slip forming. The material involved is either asphalt (which is a mixture of bitumen, aggregate and filler) or concrete. Asphalt kerb is laid by extrusion. Concrete kerb is normally laid by slip forming, but it can be laid by extrusion. Concrete kerb is also produced in the form of pre-cast sections.

5. It appears that extrusion machines were first introduced into the United Kingdom, from the United States of America, in the early 1960's. They work by forcing material through a moulding orifice by means of a mechanically driven auger. The auger has to be closely confined within a compaction tube adjacent to the mould. The reaction of the extrudate, against the kerb which has already been laid, itself gives forward motion to the machine. Such machines are automatic, in the sense that they stop if there is no material to extrude. Accordingly, if the machine has extruded all the material, it stops, and, if and when further material is loaded into the machine, pressure will build up in the auger, and the machine will move forward again.

6. As I have mentioned, asphalt kerb is produced only by using extrusion machines, but extrusion machines can also be used to extrude concrete kerb, provided that the concrete is stiff. Concrete kerbs can also be, and indeed are normally, produced from slip forming machines, which, in contrast to extrusion machines, are driven to produce forward motion. In such machines, the concrete is compacted, generally by the use of vibrators, and, as the machine moves forward, a mould of the desired shape is drawn over the compacted concrete leaving it in place. Slip forming is effectively a development of the traditional shuttered production of concrete forms. Slip forming machines often include an auger, but the function of the auger in a slip former is rather different from that in an extruder. The nature of the concrete used in the slip forming process is such that, if an attempt were made to push the machine forward by use of the extruder alone, the concrete form would collapse.

7. Until the invention claimed by the Charlesworth Patent, it appears that road building contractors in the United Kingdom used standard extrusion machines, of which the leading distributor is a United States company called Gomaco Corporation ("Gomaco"), to lay asphalt kerb on site. Such extrusion machines, however, suffer from defects. The machines have fixed weight and auger size, and the moulding section is fixed for a particular task. For a machine with those defined features to produce good quality kerb, asphalt of a certain consistency and temperature is required. However, not only does asphalt vary in its characteristics (not only from one location to another, but also from one batch to another, and even during the period over which one batch is laid, due to possible temperature variations), but it can also "bridge" or seize up, resulting in a break in the supply to the mould, resulting in wholly unacceptable kerb. Additionally, such standard extrusion machines tend to suffer from wear of the auger owing to the abrasive nature of the asphalt, and, indeed, the force required to drive the machine forward.

8. The Charlesworth Patent claims an invention to get round these perceived defects. In effect, the plaintiff contends that he has designed an extrusion machine with a hydraulically driven auger and hydraulically driven road wheels, with relay linkage between the two drives which operates in such a way that, when there is insufficient material in the auger system, the wheel drive motor stops, with the consequence that kerb can be produced without gaps. Thus the linkage circuit works in such a way, that, once the pressure in the auger drive circuit falls below a certain pre-set minimum level, the wheel drive circuit closes down. The plaintiff accepts that there is a slight defect with such a machine, namely comparatively minor ridging if and when the machine stops and starts. The plaintiff contends that the result of his invention is a machine which can successfully extrude asphalt of a wide variety of consistencies and temperatures and without excessive auger wear. Particularly significantly, such a machine stops smartly when the asphalt bridges or seizes up or when there is, for some other reason, a lack of satisfactory supply of asphalt in the auger system.

9. Since the introduction of a machine constructed in accordance with the Charlesworth Patent (which I shall call a "Charlesworth machine") the evidence suggests that road contractors in the United Kingdom have more or less ceased using machines which had been, and still are, manufactured by Gomaco, and are using Charlesworth machines instead for laying asphalt kerb. The evidence also shows that for many years the Charlesworth machine has enjoyed some 90% of the total of the United Kingdom market for asphalt extruding machines. The evidence also shows that people in the trade regarded it as a real advance over what was available previously.

10. The plaintiff carries on the business of designing, manufacturing and hiring (and, I think, selling) machines for laying asphalt. He has done this for some time, and most of his business is carried on through a company called Extrudakerb (Maltby Engineering) Limited ("Extrudakerb") which he effectively owns and runs with his wife, Joan. As I have mentioned, from shortly after the advent of the Charlesworth machine, in 1983, Extrudakerb has enjoyed something approaching a near-monopoly of the market for machines extruding asphalt kerb. It is right to add that, although the evidence relating to the period before 1983 is more exiguous, it is apparent that the plaintiff (it would appear again through Extrudakerb) had a substantial part of the market even before the Charlesworth machine started production.

11. The second defendant, Russell (known as Joe) Haley, has designed and constructed (and indeed modified) a number of different types of machine (many of them hydraulically operated and by no means limited to those extruding asphalt kerb) over the past 30 years or more. Although there is evidence to suggest that other persons may have carried out some work to it from time to time, there seems little doubt but that Joe Haley was responsible for the design and manufacture of the defendants' machine, and for at least the majority of the modifications to it. The third defendant, Valerie Haley, is his wife, and the fourth and fifth defendants, Richard and Terence Haley respectively, are their sons. In about 1993, Joe Haley designed and manufactured the defendants' machine, and from about 1995 onwards it was hired out for laying asphalt kerb on various highway contracts. Until about May 1997, when it appeared probable that it would go into liquidation (as it duly did) the first defendant, RR, a -100 company, was the company through whom this business was carried out. The shareholders and directors of RR were Joe, Richard and Terence Haley (whom I shall call "the Haleys") and Mrs Haley.

12. From about May 1997, business (including the hiring out of the defendants' machine) which would have been carried out by RR was effected by another company, the sixth defendant, Highway Management Limited ("HML"), also a -100 company, which until then had been a plant hire company. The shareholders and directors of HML are and were Joe and Richard Haley. At about the same time, the Haleys decided to change the name of the seventh defendant from Griffin Industries Limited to Relay Roads (UK) Limited ("RRUK"), a -2 company whose shares are and were owned by Joe and Terence Haley, and whose sole director is and was Joe Haley. Although there is no evidence that RRUK has used the defendants' machine to lay asphalt kerb, there is evidence that it has offered to do so.

13. The defendants' business is carried out from premises near Royston in Hertfordshire, which I visited on the second day of the hearing, 2nd October 1998. As well as inspecting the defendants' machine, I also saw it laying asphalt kerb. A number of other machines were also on view which Joe Haley informed me that he had designed and manufactured. The premises near Royston include a workshop containing a large number of different components of a mechanical, of an electrical, and of a hydraulic, nature.

14. Joe and Richard Haley have worked effectively full time in the defendants' business, and Richard Haley has frequently been responsible for the use of the defendants' machine on contracts (including driving it). The involvement of Terence Haley has been substantially less, although there is no doubt that he has organised the use of the defendants' machine, and indeed driven it, on occasions. Terence Haley ceased working for RR in September 1996, and, unlike Joe and Richard Haley, he was not involved in the day to day running of any of the defendant companies.

15. After considering the Charlesworth Patent, and the question of construction to which it gives rise, I shall turn first to the issue of infringement and then to that of validity. My assessment of the principal expert witnesses on infringement has a little bearing on my conclusions on validity.

16. I should set out claims 1 to 5 of the Charlesworth Patent:

17. The Charlesworth Patent contains three figures, two of which are diagrams of the machine, and one of which is a circuit diagram. The first figure is a side-on view of a Charlesworth machine:

18. In this figure, according to the description, the machine is passing over a road surface (5) and is extruding asphalt in kerb form (6); the auger (10) has an extension (15) into the compaction tube (16) upstream of the mould (17) which is detachable and therefore can be replaced by a mould of a different cross-sectional shape. The machine's power unit, often in the form of a diesel engine, is enclosed in a casing (7), and the machine also contains a hopper (8) with a loading hatch at the top (9) and the auger at the bottom. The auger is driven by a motor (13) via a shaft (11). The front wheels (3) are the drive wheels. Those wheels are each provided with an individual hydraulic motor, which is shown as 13a on figure 2, which is a front view of a Charlesworth machine:

19. The third figure is a circuit diagram, and it is not, I believe, necessary for me to reproduce it for the purposes of this judgment.

"Asphalt kerb extruding machine"

20. For the plaintiff, Mr Mark Platts-Mills QC (who appears with Mr Michael Tappin) contends that as a matter of construction one is concerned only with "asphalt extruders" and not with "machines which are not asphalt extruders even if asphalt could be passed through them".

22. While Mr Platts-Mills is right to warn against the risk of construing a patent by reference to the way in which the Court has construed an earlier patent, it seems to me that what Parker J. said embodies a point of principle, namely, that where a patent claims a product, rather than a process, an argument that the patent has been anticipated by an earlier disclosure cannot be defeated merely by contending that the earlier disclosure in respect of the same product was for a different purpose.

24. The issue between the parties is whether, as is contended on behalf of the plaintiff, this would cover a powered front wheel and a powered rear wheel provided that the latter is not immediately behind the former. The defendants contend for a more restrictive construction, namely that the words, taken in the context of the claim as a whole, require the wheels in question to be side by side.

25. On first reading Claim 1, it seemed to me that the construction advanced on behalf of the defendants was correct, but on further consideration I have reached the conclusion that the wider construction advanced on behalf of the plaintiff is right. It appears to me that, as a matter of ordinary language, two wheels can be said to be "laterally spaced apart" even if they are also longitudinally spaced apart: thus, as a matter of ordinary language, it appears to me that the front off-side wheel and rear near-side wheels of a motor car are "laterally spaced apart" just as much as are the two front wheels (or indeed the two rear wheels) of the same vehicle: the difference is that the front off-side wheel and the rear near-side wheel are also longitudinally spaced apart. In other words, if the contention advanced on behalf of the defendants is correct, it would involve implying a restriction into the words of the claim, and it appears to me that in a claim in a patent, just as in any other commercial document, words should only be implied if they are obvious or necessary. While the notional reader of Claim 1 of the Charlesworth Patent may well envisage that the two wheels referred to might well in practice be only laterally spaced (a view which would tend to be supported by the second figure of the patent), it does not appear to me that he would assume that the draughtsman intended the patent effectively to be so limited.

26. Two questions of construction arise in connection with these words. The first centres on the word "controlled"; the second question relates to the expression "hydraulic connection".

27. "Controlled". So far as the control envisaged by Claim 1 of the Charlesworth Patent is concerned, it is contended on behalf of the plaintiff that, taken in its context, it is concerned only with "on/off control". In effect, as Mr Wilson argues, what the plaintiff's case amounts to is that the control is not merely an on/off control, but one which is regulated so that it is only on when the pressure in the extruder has reached the desired pressure for proper extrusion. The argument on behalf of the defendants is that the control envisaged by Claim 1 is not limited to on/off control: it is said to embrace all kinds of control of the wheel drive circuit by the pressure in the auger circuit.

28. Were it not for the fact that the patent is to be read through the eyes of a person skilled in the relevant art, it seems to me that the argument advanced on behalf of the plaintiff would be unsustainable. The control envisaged in the relevant passage of Claim 1 is, on the face of it, unqualified, therefore, as I see it, in agreement with Mr Wilson, the plaintiff's argument involves implying not merely that the control is on/off, but that it is to be governed by the pressure in the extruder. However, I think that the plaintiff's argument appears rather more attractive once one takes into account that the patent is to be read through the eyes of the appropriately skilled person.

30. The fact that Mr Heron arguably agreed with Mr Platts-Mills' construction in cross-examination does not appear to me to take matters significantly further. First, his evidence on this point was given pursuant to a leading question after some earlier questions in cross-examination which led up to the leading question. While that was perfectly proper, it inevitably involved the witness being placed in a different position from that of the notional addressee of the Charlesworth Patent some 17 years earlier. Secondly, I am unconvinced that the evidence of a witness, even an expert witness, as to the meaning of the whole or part of a claim in a patent is admissible. While, as I have mentioned, the Court must construe a patent through the eyes of the appropriate skilled person, there are observations of high authority disapproving the notion that evidence, even evidence from a relevantly qualified expert, as to the proper meaning of the patent is admissible or helpful.

31. "Hydraulic connection". Mr Wilson on behalf of the defendants argues that these words have to be tied in with the reference eighteen words later to a "hydraulic control circuit"; therefore, he argues, an electrical control circuit would not be within the ambit of the words. It seems to me that the meaning of "hydraulic control circuit" is of central importance to this issue of construction, because, as Mr Wilson accepts (albeit tentatively) an electrical connection between two hydraulic circuits could be regarded as a "hydraulic connection", in the sense that it is a connection between two hydraulic circuits, but, to quote his submission, "it is quite impossible to say that an electric control circuit could be regarded as a hydraulic control circuit". As I see it, Mr Wilson's submission proceeds on the basis that the "hydraulic control circuit" referred to at that end of Claim 1 is a description of what constitutes the "hydraulic connection" referred to earlier, and also that the "hydraulic control circuit" means a control circuit which is hydraulic in nature, rather than a circuit which effects control of a hydraulic system, namely that in the wheel drive circuit. In my judgment, neither of those assumptions, inherent in Mr Wilson's submission as to the effect of the words "hydraulic control circuit", is justified.

32. In the first place, it seems to me that the "hydraulic control circuit" referred to is the wheel drive circuit, that is the circuit controlling "the road wheel drive". I consider that that follows from the words stating that "the latter [sc. "the road wheel drive"] is controlled by a hydraulic control circuit"; although not very happily worded, it seems to me that the draftsman is indicating (by the words "such that") that the effect of the "hydraulic connection" is that the wheel drive circuit is able to "sens[e]" the pressure in the hydraulic circuit of the auger drive. I believe that that construction is supported by the terms of Claim 4 which appear to envisage the "hydraulic control circuit" as being the circuit containing the fluid which provides the hydraulic pressure for the wheel drive, i.e. the wheel drive circuit, rather than being any circuit constituting the "hydraulic connection". Additionally, as a matter of ordinary language and expression, it would appear to me to be a little surprising that essentially the same thing would be referred to in the space of three lines as both "a hydraulic connection" and "a hydraulic control circuit": yet, that is what Mr Wilson's construction involves.

34. In these circumstances, I conclude that the reference to "hydraulic control circuit" at the end of Claim 1 does not assist the defendants as to the meaning of "hydraulic connection". I consider that Mr Wilson is right to concede (although he suggests that it involved stretching a point) that, on this basis, an electrical connection between two hydraulic circuits can be regarded as a hydraulic connection. After all, as Mr Platts-Mills points out, such an electrical connection will inevitably have at least one hydraulic component, in that it will have to sense the hydraulic pressure in one of the two hydraulic circuits, in this case the auger drive circuit; indeed, it will have to have a connection with the other hydraulic circuit, but that could be a purely electrical connection.

35. Even if Mr Wilson is correct in saying that the "hydraulic connection" has to be a "hydraulic control circuit", it seems to me that it would be a question of fact and degree whether a particular control circuit could be described as a "hydraulic control circuit". Thus, the fact that a particular control circuit might be partly electrical might not prevent it being a "hydraulic control circuit" as well as an "electrical control circuit". In each case, one would have to look at the machine in question, and in particular at the control circuit in that machine, and decide whether it could properly be called a "hydraulic control circuit".

37. First, the control aspect is really the central or essential aspect of the alleged invention the subject of the Charlesworth Patent. Secondly, on this hypothesis, the hydraulic nature of the connection is, as I have mentioned, not merely identified initially as a "hydraulic connection" but also in the reference to a "hydraulic control circuit". Thirdly, it appears to me that the "drive to the auger" and the "drive to the hydraulic motors of the road wheels" are each described as "hydraulic" and I do not think that it could be sensibly suggested that it was, as it were, an inessential feature of those drives that they should be hydraulic: that would tend to support the view that it is an essential feature of the connection that it is hydraulic.

38. In light of the fact that I have considered various points on this second question of construction concerning the "hydraulic connection", it may help if I summarise my conclusions:

39. Given my conclusion that the control mechanism as described in Claim 1 has a wider meaning than that contended for on behalf of the plaintiff, and given that I consider that Claim 5 does give a limiting description of the control mechanism so that it accords with the plaintiff's argument on this point, I should consider whether the plaintiff can rely upon Claim 5 to support his case on the control being on/off.

40. On behalf of the defendants, Mr Wilson contends that it is too late for the plaintiff to rely upon the independent validity of Claim 5, or indeed Claim 2, as Mr Platts-Mills seeks to do. I do not accept that contention. It is true that, in their skeleton argument, Counsel for the plaintiff did not contend that a claim other than Claim 1 had independent validity, and that Claim 2 was not even referred to in Mr Platts-Mills' opening.

41. However, Mr Platts-Mills did specifically, if briefly, argue in his opening that Claim 5 introduced the "on off" control feature if Claim 1 did not do so. Further, Mr Heron, who, as I have mentioned, was the defendants' expert witness, specifically dealt with each claim of the Charlesworth Patent separately in his report. I find it therefore hard, indeed impossible, to see how it could be contended that the defendants were taken by surprise on learning that Claim 5 was being relied on as having independent validity. Quite apart from this, given that it was clear how the reference to control in Claim 1 was being construed by the plaintiff, I have some difficulty in seeing what prejudice could be said to be suffered by the defendants by the plaintiff contending that Claim 5 had independent validity even if that took the defendants by surprise. The only additional issue between the parties would be the meaning of Claim 5, and that is a matter for legal argument, which Mr Wilson had more than sufficient time to put together. Similarly, I find it difficult to see what prejudice the defendants suffered by the plaintiff's reliance on Claim 2.

42. The only criticism which could be made of the plaintiff in connection with the contention that Claims 2 and 5 have independent validity is his failure to comply with Paragraph 10 of the Consolidated Practice Explanation [1998] RPC 18 (set out in paragraph 104/0/15 of the 1999 Edition of the Supreme Court Practice):

43. Although there was failure to comply with this Direction, no previous complaint has been made about it by the defendants, who could have asked for compliance at any time, and no prejudice has been caused to the defendants by the plaintiff's failure to comply with it. In those circumstances, to penalise the plaintiff by not permitting him to rely upon Claim 2 or Claim 5 as having independent validity, which is what Mr Wilson's submission amounts to, would to my mind be wholly inappropriate.

45. As Mr Platts-Mills observed in his closing submission, this is a somewhat unusual case so far as the issues on infringement are concerned. The dispute between the parties is not whether a defendant's product of agreed design infringes the patent, but rather as to the form that the defendants' product takes. The defendants have taken advantage of the provisions of RSC Order 104 rule 11(2)(a), to avoid having to give discovery in relation to the issue of infringement, and accordingly they have given what purport to be "full particulars of the product ... alleged to infringe, including if necessary drawings or other illustrations." Having given a description, together with figures on 17th January 1996, the defendants (through their expert witness, Mr Heron) gave a much longer description, with detailed photographs as well as figures, on 23rd March 1998, which was not only fuller than, but also was different from, the original description. That such a further description would be forthcoming was foreshadowed by the defendants at the hearing of 16th March 1998 to which I have referred.

46. As I understand it, the defendants accept that their machine would infringe the Charlesworth Patent, but for two features. Similarly, I believe that the plaintiff accepts that unless the defendants' machine has both those two features, it would not infringe the Charlesworth Patent. Accordingly, what I have to decide is whether the defendants' machine did not infringe the Charlesworth Patent because:

47. The evidence relating to both of these features ("the disputed features") was rather extensive and diffuse, and I shall try to keep my analysis within reasonable bounds.

48. Until March 1998, the defendants' case, as supported by the affidavit, and the witness statement, of Joe Haley and the witness statements of Richard Haley and a Mr Glyn Jones, as well as that of Mr Heron, was that, in the defendants' machine, there was no connection between the auger drive and the wheel drive circuits. However, on seeing the evidence on behalf of the plaintiff, the defendants admitted, through supplemental witness statements, that there had been occasions (namely in the early life of their machine up to November 1995 and for a period in the summer of 1997) when such a connection existed on the defendants' machine. However, the defendants contend that the nature of the connection was such that it did not fall within the ambit of the claims of the Charlesworth Patent. The defendants thus now admit that there has from time to time been a connection between the two hydraulic drive circuits, but contend that the connection in question was electric and not hydraulic, and that therefore their machine did not infringe.

49. The fact that the defendants now admit some sort of connection in their machine between the two circuits from time to time might suggest that it is unnecessary for me to consider the evidence upon which the plaintiff relies to establish the existence of such a connection. However, given that there remains an issue as to the occasions on which the defendants' machine had such a connection, it is right to say that I am satisfied on the evidence that, when the defendants' machine was used commercially, there was normally a connection between the two drive circuits. I believe this conclusion is supported by a number of factors. First, there is the fact (illustrated partly on video cassette and partly seen through the eyes of witnesses) that the kerb commercially laid by the defendants' machine, since it first operated commercially in 1995, is well formed, and without evidence of any significant repair or replacement of mal-formed sections. Secondly, there is the fact that that kerb contained frequent ridging. Although a number of different explanations were put forward from time to time during the hearing as to why kerb laid by the defendants' machine might manifest these features without there being a connection between the auger drive and the road wheel drive circuits, I did not find them convincing. The very fact that rather different explanations were given at different times scarcely assists the defendants on this issue. Further, when demonstrating, on three or four occasions, the laying of asphalt by their machine in the presence of the plaintiff and his advisers, the defendants were unable to produce an example of a reasonably long run of consistent well-formed asphalt kerb. Although on each occasion the defendants gave excuses based on different sorts of alleged problems, my view is that the more convincing explanation is that, when the defendants' machine was used to lay kerb in the presence of the plaintiff and his advisers, it did not have any connection between the two drive circuits, whereas when it was used to lay kerbs commercially on the occasions of which I have evidence, in the absence of a proper opportunity for the plaintiff and his advisers to inspect, there was such a connection.

50. The main explanation put forward on behalf of the defendants as to how their machine managed to lay good quality kerb, albeit with ridges, despite the absence of any connection between the two drives was as follows. The driver of the defendants' machine carefully watched the gauge showing the pressure in the auger drive, and when that pressure gauge started to drop, the operator would stop the machine. I do not find that explanation convincing. In the first place, as already mentioned, it is not entirely easy to reconcile with the demonstrations of the defendants' machine in the presence of the plaintiff and his advisers, including the site visit and demonstration which I attended on 2nd October. In those demonstrations, when there was undoubtedly no connection between the two drives on the defendants' machine, the quality of the asphalt kerb, while not bad, was not consistently good as on the other occasions (with much longer runs of kerb) in the absence of the plaintiff. Secondly, it seems to me that the degree of attention to the pressure gauge which would be required from the operator, when he also has to monitor the quality of the kerb being extruded, and to ensure that he is steering the machine along a line, appears to me to be unrealistic, particularly when one considers that it would have to persist over a long period, with the hazards, noise and other distractions on a road building site, especially as kerb laying is often carried out at night. It is not even as if the defendants always use the same operator; indeed, on one occasion it appears that the machine was operated by a trainee. Even less convincing, to my mind, was a suggestion that the machine could be stopped by listening to changes in the pitch of the engine.

51. Certain other explanations as to the presence of ridges were put forward on behalf of the defendants. These included loss of traction, problems near a gully, changing the jack settings and eccentric moving of the auger. Even assuming that these explanations were properly put to and by witnesses, it appears to me that they were, in any event, explanations which might explain an occasional ridge due to stopping the machine for a "one-off" purpose, but they did not serve to explain the degree of ridging which can be observed on the kerbing laid by the defendants' machine in the absence of the plaintiff and his advisers. These other explanations were put forward by different witnesses on behalf of the defendants, but the very fact that they came up with explanations for the first time in the witness box, and that those explanations differed from one witness to another scarcely gives confidence in any of them. As I understand it, none of these other explanations put forward on behalf of the defendants in evidence was advanced at any of the demonstrations of the working of the defendants' machine in the presence of the plaintiff and his advisers, or was mentioned in the correspondence.

52. I should mention two other explanations which were put forward by various witnesses on behalf of the defendants. Glyn Jones suggested that it might be possible to tell whether bridging was occurring by observing the asphalt in the hopper. In the first place, having inspected the defendants' machine, it is difficult to see how this could be achieved; secondly, if the pressure gauge is a reliable guide, as the initial argument for the defendants seemed to suggest, it is hard to understand what point there would be in looking at the level in the hopper; thirdly, if, as I believe, it is difficult to accept that an operative could satisfactorily concentrate on the pressure gauge, it is even more difficult to accept that he could satisfactorily concentrate on the level in the hopper, given all the other matters which required his attention when laying asphalt. Another explanation, put forward by Richard Haley, was that it is necessary to run the defendants' machine at high pressures, and to stop it frequently to allow the pressure to build up again, when the asphalt is cold. I find that equally hard to accept: although not a serious defect, it is obvious that ridging is to be avoided if possible, and there is no good reason not to use hot asphalt; additionally, this does not explain why kerb laid by the defendants' machine so often suffers from ridges: it is unlikely that cold asphalt would have been used as frequently as this explanation would require. Again, neither of these two explanations was contained in correspondence or in any of the evidence in chief of the defendants' witnesses. Another explanation, namely that ridges can be created by the repeated activation of the dead man's handle on the defendants' machine, as has been demonstrated and shown on videos provided by the defendants, appears to me to be irrelevant: it is hard to see why this should happen, unless one of the other explanations, which I have rejected, is correct.

53. Given that it is common ground that the ridges are present because of stopping and starting the machine, the question is why the defendants' machine does stop and start when laying asphalt kerb commercially (as evidenced by the ridging on that kerb). I agree with Mr Platts-Mills's submission, that the defendants have been unable to come up with a coherent or convincing explanation as to how they have been able to use their machine to produce many miles of well-compacted kerb without malformed sections or repairs, but with ridges, and that the only sensible conclusion on the evidence is that on each such occasion there has been a connection between the auger circuit and the wheel drive circuit, whereby the former effectively controls the latter on an "on/off" basis.

54. I have thought it right to spend a little time on this issue, even though it is conceded to an extent by the defendants, not only because it is necessary for me to decide the frequency with which there was a connection between the two drive circuits in the defendants' machine when laying asphalt commercially, but also because my conclusion casts doubt on the reliability of the evidence given by various witnesses on behalf of the defendants.

56. The explanations as to why none of the defendants' witnesses mentioned the existence of the connection between the two drive circuits in their original witness statements were, I regret to say, quite unconvincing. The defendants' witnesses, and in particular Joe Haley, Richard Haley and Glyn Jones, were well aware of the importance in this litigation of the question of whether there was or ever had been a connection between the two circuits. Joe Haley's explanation, in his subsequent witness statement, for the positively inaccurate statement in his affidavit, was that, although there had been a connecting switch on the defendants' machine originally, he had told Terence Haley to take it off in November 1995 because it was unreliable, and that he had only learnt recently that Glyn Jones had used the pressure switch, but, had he learnt earlier, he would have recalled the earlier connection, which he would have mentioned. The later statements of Richard Haley and Glyn Jones purport to support this story. Regrettably, this story is not only unconvincing in itself, and did not come across convincingly when advanced by each of the three people from the witness box, but Glyn Jones said that Joe Haley learnt that he had put a connection between two circuits into the defendants' machine in the summer of 1997, which was considerably before the affidavit in which Joe Haley swore that there was no connection, and of course before the first round of witness statements. This reinforces my view that the evidence of Joe and Richard Haley and Glyn Jones must be considered very sceptically, a view which I believe is supported by the way in which they tried to explain the quality of, and ridging on, the kerb laid commercially by the defendants' machine.

57. Quite apart from this, Joe Haley confirmed on affidavit that, when the defendants' machine was used at Eaton Socon, there had been no modifications to any aspect of the machine over and above what had been previously described. In other words, he was clearly saying on affidavit that there was no connection at that time between the two circuits. That was confirmed by Mr Heron, the defendants' expert. Subsequently, the defendants' then solicitors adopted a slightly more cautious line in correspondence, merely not admitting that there was such a connection. It is now admitted by Terence Haley that in fact there was a connection between the two circuits in the defendants' machine when it was being used at Eaton Socon. Mr Heron admitted that he had not done a particularly good job on his first inspection. With a machine whose circuits had been prepared on an ad hoc basis, and which had been so frequently altered as the defendants' machine, and with clients who, I suspect, regrettably, were prepared to let him be misled, one cannot avoid having some sympathy with Mr Heron. However, I am bound to say that he does not seem to have put the same degree of care and effort into investigating and analysing the defendants' machine as the plaintiff's experts, Mr Turton and Mr Dyos, or indeed, the plaintiff himself.

58. Additionally, I do not accept Glyn Jones' evidence as to how he came to fit a pressure switch into the defendants' machine in the summer of 1997. He said, in so doing, he was acting entirely on his own initiative, and that he looked for and found an appropriate switch and manifold at the back of the defendants' stores. That was unconvincing for a number of reasons. First, Mr Jones was only a sub contractor of RR, not an employee. Secondly, according to Mr Jones himself, he knew from his previous employment with the defendants that a pressure switch had not worked, and that Joe Haley had required it to be removed and (possibly) that Joe Haley had said that it should not be put back. Thirdly, Mr Jones said that he did not know what the pressure switch or the manifold on which it was mounted looked like, where to plumb it hydraulically into the machine, or where to connect it electrically into the machine. Fourthly, Mr Jones's supplemental witness statement suggested he had used the pressure switch on a number of occasions, but he now suggests that the use was only on one morning.

59. Accordingly, I conclude that, save when it was being demonstrated in the presence of the plaintiff and his advisers, and perhaps with one or two other exceptions, the defendants' machine, when it was used commercially from some time in 1995 until the issue of these proceedings and thereafter did have a connection between the two drives.

60. Given my conclusion that there is a connection between the two drive circuits in the defendants' machine, the question which then has to be considered is whether or not the nature of the connection is such as would bring it within the ambit of Claim 1, 2 and/or Claim 5 of the Charlesworth Patent. In this connection, the essential question is whether or not the connection was "a hydraulic connection" within the meaning of Claim 1.

61. The defendants accept that there was what they call "a pressure switch" (an expression which I am content to adopt for the purpose of this judgment) connecting the two circuits in the defendants' machine from time to time, but they contend that this was not "a hydraulic connection" within the meaning of the Charlesworth Patent. On behalf of the plaintiff, three arguments are put forward in reply. The first is that the pressure switch was "a hydraulic connection"; the second is that, even if the first argument is not right, the Charlesworth Patent does not, on its true construction, require the connection to be hydraulic; the third argument is that the defendants' machine employed a purely hydraulic connection from time to time as well as the pressure switch. I shall consider these three arguments in turn.

62. So far as the first argument is concerned, I am satisfied that the pressure switch which, even on the defendants' case, was included in the defendants' machine (albeit that the defendants do not accept that it was present as frequently as in my view it clearly was), was "a hydraulic connection" within the meaning of Claim 1. I do not intend to set out my reasoning, because it is, I hope, to be found in the passage where I consider the meaning of a "hydraulic connection" when considering the construction of the Charlesworth Patent.

63. Before turning to the second and third arguments raised by the plaintiff, it is right to consider whether, even on the defendants' construction (which I have rejected), the pressure switch in the defendants' machine constituted a "hydraulic connection" within the meaning of Claim 1. In this connection, it should be explained that the pressure switch works as follows. When the hydraulic pressure in the auger circuit reaches a certain level, the switch sends an electric signal to a hydraulic solenoid valve. The minimum pressure level required to activate the switch can be adjusted to correspond to a desired minimum level of auger motor pressure, and hence a minimum degree of compaction of the asphalt of the asphalt in the compaction tube and mould. When, and only when, the hydraulic solenoid valve is energised by the signal sent by the switch, it allows oil to flow in the road wheel drive circuit. There is no doubt that Mr Platts-Mills is correct in contending that the pressure switch and associated wiring amount to a connection between the auger motor hydraulic system and the wheel drive motor hydraulic system: that does not, however, dispose of the question whether it can be called a "hydraulic connection" within the defendants' construction of those words.

64. In my judgment, however, the pressure switch admittedly on the defendants' machine is such a "hydraulic connection" even on the defendants' construction of those words. As I have already indicated, it seems to me that Mr Platts-Mills is correct in his contention that a connection can be described as "hydraulic", even if it is not exclusively hydraulic. It appears to me that the system admittedly on the defendants' machine, namely the pressure switch, is a "control circuit" which is partly electrical and partly hydraulic. As I have indicated, it seems to me that, on the true construction of the Charlesworth Patent, the relevant "connection" and "control circuit" must be hydraulic, but need not be exclusively hydraulic. On the facts of the present case, it appears to me that the pressure switch system on the defendants' machine is, albeit by a short head, a "hydraulic connection" and does represent "a hydraulic control circuit".

65. Before turning to the second and third arguments on this aspect raised on behalf of the plaintiff, it is right to deal with a further argument raised by Mr Wilson, namely that the defendants' machine was not set up so as to work in accordance with the teaching of the Charlesworth Patent: it merely had a sensor to observe when the auger screw was empty (i.e. when there was effectively no pressure in the auger circuit) and the machine stopped at that stage. I agree with Mr Platts-Mills, that there is no evidence to support this argument, and in particular it is to be remarked that neither of the individuals called on behalf of the defendants who had actually operated the defendants' machines with the pressure switch (namely Terence Haley and Glyn Jones) gave evidence to support this argument, or were even asked questions in connection with it. Indeed, as I understood it, the effect of the evidence of those witnesses was to the effect that they were seeking to get the pressure switch to work so as to detect drops in pressure in the auger circuit system and not merely the absence of any pressure in that circuit.

67. I turn, then, to the third argument advanced on behalf of the plaintiff, namely that there is reason to believe, and I should find, that the defendants' machine was used for a substantial period with a purely hydraulic connection rather than the pressure switch i.e. a switch which, even on the construction most favourable to the defendants, was a "hydraulic connection". The evidence to support this argument is circumstantial, inferential and, indeed, somewhat complicated. Because the plaintiff's case effectively relies purely on inference and circumstantial evidence, and also involves my holding that at least one of the Defendant's witnesses, namely Joe Haley, was deliberately concealing the truth when giving evidence, it is with some hesitation that I have reached the conclusion that the plaintiff's third argument is correct, and that the defendants' machine did sometimes have a purely hydraulic circuit connection between the two drive circuits from time to time in place of the pressure switch.

68. It is clear from inspecting the defendants' machine, from the oral evidence of the defendants' witnesses, and from the expert evidence of Mr Turton and Mr Dyos on behalf of the plaintiff, and of Mr Heron on behalf of the defendants, that the circuits inside the defendants' machine are complicated (Mr Heron, a hydraulics expert, described the hydraulics as "a mare's nest", not, perhaps, strictly the right expression, but his meaning was clear). It is also apparent that the electrical and hydraulic circuits in (and indeed the mechanical parts of) the defendants' machine were frequently altered, principally by Joe Haley. Although the circuits were complicated, none of the defendants' witnesses admitted to any expertise in the design of hydraulic circuits. The individual most concerned with designing machines, including the defendants' machine, on the defendants' side, Mr Joe Haley, said on several occasions that he was not a hydraulics engineer, and on one occasion said he was not an electrician. Indeed, he suggested that other persons, namely his sons Terence and Richard, or Glyn Jones, had been responsible for the hydraulics, but that was not at all convincing: none of those witnesses suggested that they had any knowledge of hydraulics, or much knowledge of electrical circuits.

69. In my judgment, Joe Haley is a competent and experienced, if not professionally qualified, hydraulics engineer. On his own evidence, he had been involved for over 30 years in designing and building a number of different machines, some of which he pointed out to me at my inspection of the defendants' premises on the 2nd October. Regrettably, but consistently with his failure to divulge the existence of any connection whatsoever between the two circuits in his original witness statement and in his affidavit supporting the original description of the defendants' machine, I consider that, as Joe Haley appreciated, there are features of the defendants' machine which are inexplicable unless it had from time to time included a purely hydraulic connection between the two circuits. I also take the view that Joe Haley pretended disingenuously to know little about hydraulic systems, whereas he was the individual primarily responsible for designing and constructing the defendants' machine, and for modifying it on a number of occasions in different ways.

70. The principal piece of evidence upon which the plaintiff's case relies is a valve (marked 108 on a circuit diagram, and hence known as "valve 108") in the wheel drive circuit together with associated connections. The plaintiff also relies on the nearby presence of a location of a source of auger pressure, as well as the existence of a system of travel overriding the dead man's handle included on the defendants' machine. Valve 108 was discovered by Mr Heron, the defendants' expert, in March 1998, and, although he clearly considered its existence to be of importance, and the defendants must have understood this, no explanation was given for its presence until the hearing. The explanation given at the hearing for valve 108 by Joe Haley was that it had been included in the machine as a dump valve between the auger and the cross-auger, at a time when the machine had included a cross-auger, and, when the cross-auger was abandoned, valve 108 became redundant, but was nonetheless left in the auger drive return line. Apart from having been given for the first time in the witness box, this evidence was unsatisfactory for a number of reasons. First, Joe Haley was quite unable to say how the valve 108 was plumbed in, where the pressure was sent, or even how the valve worked; secondly, he was unable to explain why after it had become redundant, the valve 108 was not merely retained, but was re-plumbed into the wheel drive circuit: such re-plumbing involved fairly extensive consequential metal work, and also involved making the wheel drive circuit considerably more complex than it would otherwise have been, as Mr Heron, the defendants' expert, himself said. A significant amount of metal work and a significant amount of connective hosing could have been dispensed with if valve 108 was removed from the wheel power drive line, and, despite significant modifications having been effected to that line since the inclusion of valve 108 within it, the valve 108 remains. On the defendants' case, not only is the presence of the valve 108 in the wheel drive power line inexplicable, but the failure to remove it from that line, particularly when other modifications were being carried out to that line, remains unexplained. Even without my conclusion that Joe Haley was responsible for the original design and construction of, and for the modifications from time to time to, the defendants' machine, I find his evidence very hard to accept.

71. I turn to consider the explanation put forward on behalf of the plaintiff for the inclusion of the valve 108. In this connection, Mr Dyos suggested that the current arrangement within the defendants' machine could be readily adapted to create a purely hydraulic connection between the two systems in one of two ways. The first would involve replacing the "normally closed" valve 108 with a "normally open" valve; the second would involve a re-plumbing of the existing components in the circuit using all the current components, including valve 108, albeit with an internal modification. Neither of these two options would be possible if valve 108 and its associated connections were removed, because the connections currently contained in valve 108 would not be present.

72. Another piece of evidence which also tends to support the plaintiff's case on this point (albeit that it is again only of inferential circumstantial value) is the fact that, in late 1997 and early 1998, the defendants' machine (as photographed) had a pipe dangling with a simple plug, which need not have been retained if there was a pressure switch; it has been recently replaced by a quick release connection. No explanation was advanced on behalf of the defendants as to why either of these features was included, but it was accepted by Mr Joe Haley that the dangling pipe or the quick release coupling would enable the auger pressure to be used in the drive circuits as put forward by Mr Dyos. Similarly, the presence of a warning light in the defendants' machine appears to me to be consistent with the plaintiff's case on this point: on the defendants' case, the warning light performs the useless function of informing the operator that he is holding the dead mans' handle (which he would obviously know); on the plaintiff's case, the light would have the useful function of telling the operator that the necessary pressure had been reached.

73. Joe Haley, as well as the other witnesses called on behalf of the defendants, denied that any purely hydraulic connection between the two circuits in the defendants' machine had ever existed. Given the fact that I have concluded that these witnesses, namely Joe Haley, Richard Haley and Glyn Jones, and to a lesser extent Terence Haley, gave consistently inaccurate evidence about the presence of the pressure switch, and matters connected therewith (as I have discussed above) I cannot give any significant weight to their evidence on this issue.

74. However, I do not find it easy to decide whether the circumstantial and inferential evidence relied on by the plaintiff establishes that there was on occasion a purely hydraulic connection between the two drive circuits on the defendants' machine. Not only is there no direct evidence of such a connection, but, as Mr Wilson points out, if the defendants' machine included the pressure switch, what need would there have been for a hydraulic connection at all? Despite the points which can be made the other way, I have reached the conclusion that the plaintiff has, on the balance of probabilities, established that, from time to time when the defendants' machine was used commercially, it did contain such a purely hydraulic connection. There is no other sensible explanation for certain features in the complicated circuits in the defendants' machine, as I have tried to explain. Given that Joe Haley was plainly in the habit of carrying out many alterations to the inside and outside of the defendants' machine, it would not strike me as at all surprising if he had experimented at different times with various sorts of connection between the two drive circuits.

75. Accordingly, so far as the first of the disputed features, namely the existence of a connection between the two drive circuits on the defendants' machine, is concerned, I have reached the conclusion that the plaintiff succeeds on his first argument (whoever is correct on the proper meaning of "hydraulic connection"), that he would fail on his second argument (if the pressure switch is not a "hydraulic connection", contrary to my conclusion), but that he succeeds on his third argument (namely that there was at times a purely hydraulic connection, not being the pressure switch, between the two drive circuits on the defendants' machine from time to time).

76. The question here is whether, in addition to the driven rear wheel(s), one (on the plaintiff's case on construction) or both (on the defendants' case on construction) of the front wheels are, or one of them is, driven by a hydraulic motor. The defendants deny using any such front wheel motors at any time since an early experimental stage of the defendants' machine in 1993, and, in particular, they deny that there were any front wheel motors on the defendants' machine on any contract on which it was used.

77. The primary evidence called on behalf of the plaintiff on this issue had three components. First, there was the evidence of the plaintiff. He took photographs at a site on the A1 at a place called Bloody Oaks where the defendants were using their machine to lay asphalt kerb. The photographs are somewhat blurred and indistinct, because they were taken from a moving vehicle. Various versions of the same photographs were considered in some detail in evidence. I am not satisfied that the two photographs upon which the plaintiff primarily relies do establish the presence of a motor on one of the front wheels of what is admittedly the defendants' machine. Where a somewhat unclear feature on a poor photograph is claimed to establish the presence of a motor but is sought to be explained, for instance, by shadowing, a trick of the light, a shaking hand when taking the photograph, the effect of blurring, or a combination of some of those causes, and in any event it is suggested that the specific shape relied on does not look like a motor (all of these points having been taken by the defendants) it seems to me that, unless the photographic evidence is pretty clear, the Court should be very cautious before reaching the conclusion that a motor was present in the absence of any evidence from a photographic expert. I do not consider that any relevant conclusion can satisfactorily or fairly be drawn from the photographs, at least in the absence of any relevant expert evidence. It is right to say that, although the photographs taken by the plaintiff are insufficient to persuade me that they show a front wheel motor on the defendants' machine, they are not inconsistent with the presence of such a motor.

78. During this visit to Bloody Oaks, the plaintiff said that he tried to inspect the defendants' machine visually as well by getting as close as he could on foot. He said that he observed a chain drive sprocket on the inside of the left hand front wheel on that occasion, evidence which I am inclined to accept: even though the plaintiff referred to his view of this as "somewhat fleeting", it was not directly denied by any witness called on behalf of the defendants. The plaintiff struck me as honest; he was an expert and he knew what he was looking for. Of course, I take into account the fact that he is biased.

79. The second piece of direct evidence relied on by the plaintiff was given by a Mr John Bowden. He said that he had seen drive on the front wheels of the defendants' machine on 26th June 1995, at a time when he was delivering a machine called a Curb Cadet manufactured by his employers, Gomaco International Ltd ("Gomaco International") the UK subsidiary of Gomaco, to the defendants. He said that he had experience of poor traction on the Curb Cadet, and was at first glance surprised to see that the defendants' machine appeared to be driven by two small back wheels; however, he said that, on looking at the front of the machine, he saw that the front wheels were driven too, and this satisfied his curiosity.

80. There are criticisms which can be made of the value of Mr Bowden's evidence. Thus, he did not spend much time looking at the front of the defendants' machine, explaining that he would have been concerned about appearing discourteous if he examined it too closely; rather more significantly, when cross-examined, he said that he could not be sure that what he saw was not the silvery clutch or break device which is attached to the hub of the front wheel of the defendants' machine. When it was put to him that this is what he might have seen, he said "I cannot say "yes" or "no", simple as that".

81. In my judgment, Mr Bowden's evidence is of real value to the plaintiff's case. He was a convincing witness, both in the sense of the impression he gave and, rather more importantly, in the sense that he was not dogmatic or opinionated, and he clearly had no interest in the outcome of these proceedings. While I appreciate that he did not look at the defendants' machine in great detail, I regarded it as very significant that, albeit that his reasons were different from those raised by the present proceedings, he was looking for precisely the things whose existence is in issue in the present case, namely motors on the front wheels of the defendants' machine. His evidence is also valuable because it is from someone who is not merely objective, but someone who is a qualified engineer of 20 years experience and who knew and knows about machines of the sort with which these proceedings are concerned. That fact that he did not look for a prolonged time or in great detail does not seem to me to carry much weight, because, as he said, he was specifically concerned to see whether the front wheels of the defendants' machine were "driven" as he put it, and, once he satisfied himself that they were, he had no further concern. While it would be a little unfair to characterise his interest as idle curiosity, it was not a great deal more than that, and in those circumstances, particularly with the passage of time, it is perhaps not surprising that he could not be sure that the front wheels of the defendants' machine had motors attached. Mr Wilson's contention, that Mr Bowden's uncertainty as to whether he really saw a motor on each of the front wheels was shown to be so great in cross-examination that it renders his evidence wholly unreliable, seems to me to go much too far. Mr Bowden's evidence (particularly his answer relied on by Mr Wilson and which I have quoted) must not be taken out of context, and it appeared to me from his oral evidence that after, as well as before, that answer, he still was fairly clear in his own mind that he believed that what he had seen on the front wheels of the defendants' machine were motors. Furthermore, I think there is force in Mr Platts-Mills's contention that, when Mr Bowden expressed himself in cross examination in the words I have quoted, he was being shown part of the front wheel structure of the defendants' machine in isolation, and not the actual front wheel with the structure mounted on it; nor was he reminded as to how the structure he was being shown during cross examination related to the positioning of the wheel.

82. In my judgment, Mr Bowden was an independent witness with ideal qualifications who said that he specifically inspected the front wheels of the defendants' machine to see if they had motors on, and had a good reason for such an inspection, and who plainly satisfied himself at the time that such motors were present. While I accept there is a possibility that, because his interest was little more than idle curiosity, and because the inspection was somewhat cursory, Mr Bowden could have been mistaken, I have little hesitation in concluding that, on the balance of probabilities, he was not mistaken in what he now thinks he saw in mid-1995.

83. Of course, when Mr Bowden carried out his inspection, the defendants' machine was on the defendants' premises and was not being used. However, if Mr Bowden's evidence is correct, it is nonetheless significant, because it would be entirely inconsistent with the defendants' case, and all the relevant evidence given on behalf of the defendants, which was to the effect that there had been no motors on the front wheels of the defendants' machine since 1993, whereas Mr Bowden's inspection was in 1995. Further, it is a little difficult to see why the defendants' machine should have had motors attached to the front wheels in 1995 at the defendants' premises, if it did not have such motors when it was being commercially used at that time.

84. The third piece of direct evidence relied on by the plaintiff is that of Mr Shaun Davey, a labourer currently employed by Extrudakerb. He said that he has worked "on and off" for Extrudakerb since about 1994, but has also worked for the defendants. In particular, he worked for the defendants when the defendants' machine was being operated commercially in the last quarter of 1995. He said that the defendants' machine was housed in a van, and there were various small drive motors kept in the van. His evidence was not only to the effect that the defendants' machine "had an automatic stop-start facility" but also that the defendants' machine had an "extra drive motor", namely a motor attached to at least one of the two front wheels. In his oral evidence, Mr Davey said that he was quite clear in recollecting that what he saw was a drive motor on the inside of the front left wheel of the defendants' machine. Mr Davey was, at least on the face of it, an attractive and convincing witness, but, while accepting that, Mr Wilson contended that a closer analysis of Mr Davey's evidence indicated that it could not be relied on.

85. Mr Wilson contended that, in light of the evidence of Mr Davey and Mrs Charlesworth, there was reason to believe that Mr Davey had been inconsistent in his evidence. Mrs Charlesworth said in her evidence that she had understood him to say that the motor in question was connected to the right hand front wheel of the defendants' machine. Indeed, Mr Wilson suggested that Mrs Charlesworth and Mr Davey may have got together with a view to fabricating Mr Davey's evidence. While it is right to acknowledge that Mrs Charlesworth was very positive in her evidence, I do not consider that this line of argument has any validity. If anything, it involves criticism of Mrs Charlesworth, rather than of Mr Davey. Mrs Charlesworth struck me as a little confused and somewhat obstinate, but it is fair to her to add that she certainly did not strike me as dishonest. At some point she must have got it into her head that Mr Davey was referring to the right hand wheel, whereas he was in fact referring to the left hand wheel, but I am wholly unsatisfied that this demonstrates that Mr Davey's recollection is unreliable; I am even less prepared to accept that there is any remotely convincing evidence to the effect that Mrs Charlesworth had coached Mr Davey in relation to his evidence. He struck me as an honest man. His evidence in cross-examination was consistent with his evidence in chief and with his witness statement. Mr Davey's evidence is not inconsistent with there being a motor on the right front wheel, as well as on the left front wheel: it is merely that Mr Davey did not see the right front wheel.

86. The evidence on behalf of the defendants was that there was no motor attached to either of the front wheels of the defendants' machine, save at a very early experimental stage. All the witnesses called by the defendants were quite clear in their oral evidence that neither of the front wheels of the defendants' machine had had motors since the early experimental days. The weight I give to that evidence is substantially less than might otherwise be the case, because of my conclusion that the same witnesses were not telling the truth in relation to the "hydraulic connection". However, it is fair to say that the mere fact that a person does not tell the truth on one matter does not necessarily mean that he is not telling the truth on a different matter.

87. While on its own, it might well be wrong to make anything much of it, it is to be noted that Glyn Jones, in paragraph 12 of his witness statement, said, in relation to the defendants' machine, that "the driven wheels are steered using a normal steering wheel". When it was pointed out to him that this indicated that the front wheels were indeed "driven", he said that this was a mistake, and should read along the lines "the steering wheels are steered using a normal steering wheel". Mr Platts-Mills contends that the original version is correct, and, unintentionally from the defendants' point of view, gives the game away; Mr Wilson says that the original witness statement was perhaps rather imprecisely expressed, and was correctly rephrased by Glyn Jones in his oral evidence. In the absence of any other evidence supporting the existence of motors on either of the front wheels of the defendants' machine, I would be very reluctant to place much weight on what could be explained as being a somewhat careless use of words. However, on the facts of the present case, I consider that the way in which Mr Jones expressed himself in his original statement is of some significance.

88. I turn to consider the indirect evidence on this issue. The defendants rely on the failure of the plaintiff to produce any photographic evidence (other than that which I have rejected as being unhelpful) of the defendants' machine with motors on the wheels. I accept the answer put forward by Mr Platts-Mills: the plaintiff could not go on site with a view to photographing the defendants' machine working save with the consent of the main contractor; when such consent has been purportedly sought by the defendants at the instigation of the plaintiff, it has been on terms which would scarcely encourage the contractor to agree. If one cannot actually come on site, it is difficult to photograph the defendants' machine in operation, because any photograph would have to be taken from a motor vehicle moving along the motorway in a contra-flow system, and, as the photographs in this case show, this results in unsatisfactorily blurred photographs.

89. More powerfully, Mr Wilson points on behalf of the defendants that, at least on the evidence so far provided, there is no way to fit a drive motor to either of the front wheels of the defendants' machine except through certain existing holes (which had been used, on the defendants' evidence, for motors during the experimental period) and none of the evidence on behalf of the plaintiff suggests that a motor was fixed on either of the front wheels on this basis. Mr Platts-Mills seeks to meet this point by suggesting that the defendants had a spare set of hydraulic front saddles and wheels for use when it suited them, a notion which Mr Wilson dismissed as "sheer fantasy", pointing out that there is no evidence from any photograph or any witness (including Mr Davey) that such saddles existed. Further, Mr Wilson points out that the defendants are unlikely to have a saddle intended to deceive the plaintiff and his advisers about the existence of motors on the front wheels, while retaining the holes for the original motors: the defendants would be far more likely, he argues, to have a yoke without any holes for motors, if their desire was to deceive. Further, he says that it is unlikely that the defendants would have a separate yoke with the machine at all times, so as to be able to attach motors of the sort which the plaintiff alleges; he also relies on the absence of any evidence from Mr Davey that such existed. Although Mr Davey did not say that he saw any spare wheels or saddles in the back of the lorry on the occasion that he looked, it is clear that the defendants kept various spare parts for the defendants' machine in the back of the lorry, and it is therefore by no means impossible that this included spare wheels, yokes or saddles on occasion.

90. In the end, and in light of all the other evidence, I have concluded that this set of points does not represent a real obstacle to accepting the plaintiff's case on this issue. It is clear on the evidence that many different variations of the defendants' machine existed from time to time. At Bloody Oaks, it appears that the front yoke was ready and able to take a drive motor and chain, of the type originally used by the defendants, when it emerged from the lorry. On the basis of Mr Davey's evidence, prior to the machine being moved into the lorry the defendants had adopted a front wheell drive. That suggests that the yokes could be replaced. Further, it appears that the defendants were content to remove and replace the yoke and wheel at the rear at least two or three times in the comparatively short history of their machine. Thus, the defendants have replaced the original two rear wheels with a single, much larger wheel, with a heavy tread.

91. I am also of the view that the plaintiff's case derives some assistance from the fact that, when they noticed him looking at, and photographing, the defendants' machine, the defendants drove it into a lorry and kept it there for some time, before coming out of the lorry with the machine, and then it was covered with a tarpaulin. The obvious, or, at any rate, an obvious, explanation for this rather unusual, indeed suspicious conduct was that the defendants wished to hide their machine from the plaintiff. While there could be other explanations for this (although none has been put forward), the obvious one which suggests itself is that there was an aspect of the defendants' machine when at Bloody Oaks, which might or would harm the defendants' case in these proceedings, the most likely aspect being a motor on one or both of the front wheels. The evidence of Terence Haley, who was present at Bloody Oaks at the relevant time, was not consistent or satisfactory and supports my suspicion of the defendants' denial. In his witness statement, he disputed the time during which the defendants' machine was in the trailer, while at one point in his oral evidence, he said that it was not put into the trailer at all; further, in his evidence, he denied having previously seen the photographs taken by the plaintiff at Bloody Oaks, whereas he had commented on them in his own statement.

92. As to other inferential evidence, each party suggests that there were good practical reasons as to why the other party's case as to the existence or non-existence of front wheel motors was unconvincing. For the plaintiff, it is contended that the defendants' machine would suffer from wheel spin, due to poor traction, if there were no motors attached to the front wheel. In this connection, there is evidence of wheel spin on some of the videos of the working of the defendants' machine in the presence of the plaintiff - i.e. when there was no front wheel drive. This was explained variously by the defendants and their witnesses as an undulation in the surface (Glyn Jones) or a wet surface (Glyn Jones, Joe and Richard Haley). I am not satisfied with either of those explanations. So far as undulations are concerned, I could see none on the relevant videos. As to the wet surface, there was no evidence suggesting that the surface at Whittlesea, where the demonstration was taking place in the case of one video, was at all wet. Furthermore, although it may not be satisfactory to lay asphalt kerb in pouring rain, it must presumably be desirable to have a machine which can lay asphalt kerb on a wet surface.

93. Furthermore, Mr Platts-Mills argued that it would be desirable for the defendants' machine to have driven front wheels, because it is so designed that its weight might be taken off the back wheels from time to time, with the result that it would slip on those wheels if the front wheels had no motor. He contended that Joe Haley's explanation for moving the drive to the rear namely because the weight of the machine was largely at the back and therefore having motors on the front wheels only produced poor traction, had been convincingly disposed of by one of the plaintiff's two expert witnesses, Mr Dyos, on the following basis. The weight of the defendants' machine is situated between the front and back wheels, the gas bottles and hydraulic fluid tank are at the front, and the hopper is fairly central. The defendants' machine requires the mould being close against the ground, as otherwise the kerb will not properly be formed, and this tends to cause the rear wheels to lift, which in turn would tend to cause the rear wheels to spin, unless the front wheels were driven. Mr Dyos's evidence on this aspect struck me as tolerably convincing. Certainly, the fact that the only oral evidence to the contrary is that of Joe Haley does not cause me to doubt it: as I have mentioned, although he is clearly a talented man, I do not believe that Joe Haley was an honest witness in connection with many issues in these proceedings.

94. On the other hand, Mr Wilson contends that it was inherently unlikely that the defendants' machine would have had front wheel drive as well as rear wheel drive, because it would have been actually disadvantageous to the working of the machine. The evidence relied on by Mr Wilson in this connection was largely gleaned by him in cross-examination of Mr Dyos; that evidence indicated that any front wheel drive would have been unlikely to have been connected in series with the back wheel drive because it would have been difficult to match, and that if the connection had been in parallel with the rear wheel drive, it would have significantly reduced the speed at which the machine could travel, unless the rear motor was swapped at the same time as the front motors were fitted, and in any event this would not have assisted with the traction problem, because, when one wheel spins, the rest stop.

95. In my judgment, in light of the evidence of fact, and in particular the evidence of Mr Davey to the effect that the defendants appear to have carried many different motors around in the van containing the defendants' machine, the evidence relied on by Mr Wilson does not really call into question the likelihood of the defendants' machine being driven from the front as well as the back. I accept the argument that it is unlikely that any front motor or motors would have been connected in series with any rear wheel motor: that is indeed the effect of Mr Dyos's evidence. On the other hand, it does not seem to me at all unlikely that the two sets of motors could have been connected in parallel. First, although this would have involved the defendants' machine being able to proceed only at a significantly lower speed in the absence of any change of the rear wheel motor, it seems to me that, at least on many occasions, it would have been worth sacrificing some speed in return for satisfactory kerb laying. Secondly, and even more strongly, I consider that there would have been no loss of speed if the fixing of front wheel motors or motor had been accompanied by the replacement of back wheel motors or motor (connected in parallel); given Mr Davey's evidence (which I accept) that a number of different motors were carried around by the defendants with the defendants' machine, as well as the evidence (which I also accept) that the defendants, and in particular Joe Haley, made frequent and quite significant changes to their machine from time to time, it seems to me perfectly possible, indeed quite probable, that the defendants did effect such a change to the rear wheel motors.

96. In these circumstances, I reach the conclusion that the plaintiff has established its case on the second of the disputed features, and that, contrary to the evidence given on behalf of the defendants, the defendants' machine has been used commercially on a number of occasions with front wheel drive. On the balance of probabilities, I consider that both of the two front wheels of the defendants' machine had motors. It is fair to say that the evidence to support the contention that the two front wheels had motors is substantially less than the evidence that one of those wheels, namely the left wheel, had a motor, but to my mind, on the balance of probabilities, the plaintiff has established its case on both front wheels. I bear in mind in particular Mr Bowden's evidence.

97. For the reasons indicated in the previous two sub sections of this judgment, I have come to the conclusion that, despite the evidence and submissions on behalf of the defendants, their machine had both a "hydraulic connection" between the motor drive and the auger drive circuits and had "two laterally spaced apart road wheels each having an individual hydraulic drive motor". Although the point was not, I think, directly addressed by counsel, it is, strictly speaking, necessary to consider whether the defendants' machine, when being used commercially, had both these features at the same time. Thus, it would be possible that the defendants' machine, when in use commercially, could have had one of the disputed features, but not both at the same time: in that event, given that, in order to infringe, the defendants' machine would have to have each of the disputed features, it would seem to me that it would not infringe.

98. I am satisfied, however, that there were frequent occasions upon which the defendants' machine was used commercially when it contained both the disputed features. First, each of the disputed features enabled the defendants' machine to be operated significantly more effectively than if either feature had been absent. Secondly, there is the evidence (from videos and photographs, and from certain witnesses called by the plaintiff) as to the good quality of the kerb laid by the defendants' machine (at least in the absence of the plaintiff and his advisers). Thirdly, there was no good reason for the defendants omitting either of the disputed features from their machine, save I suppose, that they would not want to do so if they thought there was a real possibility of the plaintiff discovering their presence.

99. Accordingly, the plaintiff succeeds on the issue of infringement.

100. The Haley family operated their business initially through the first defendant, RR, until it went into liquidation, and thereafter through the sixth defendant, HML. The conclusion that the defendants' machine infringed the Charlesworth Patent must mean that the plaintiff succeeds against RR (who, it will be recalled, is not represented before me) and also against HML (as I understand Mr Wilson to accept). RRUK also is liable on the evidence as to its threatened use of the defendants' machine.

101. I turn to consider the claims made against the individual defendants. The plaintiff's claim against the third defendant, Mrs Haley, was abandoned during the course of the trial. I am satisfied that Joe Haley designed the original version of the defendants' machine, and was responsible for the great majority, and possibly all, of the various modifications to it, and indeed was mainly responsible for building the defendants' machine and making the modifications. I am also satisfied that Richard Haley operated, and therefore used, the defendants' machine commercially at times when it infringed the Charlesworth Patent, and that he knew that to be the case. In those circumstances, the plaintiff has established his case on infringement against each of those two defendants pursuant to Section 60(1)(a) of the Patents Act 1977.

102. Similarly, it seems to me that Terence Haley is liable under that section because he admits to having driven the defendants' machine commercially on occasions. Having been abroad for a substantial proportion of the relevant period for the purpose of these proceedings, I am satisfied that he was less involved in infringing acts than his father, Joe, or his brother, Richard, both in the sense of his knowledge or belief as to whether or not the defendants' machine infringed and the frequency which he used the defendants' machine. The question might be raised as to whether he appreciated that the defendants' machine infringed the Charlesworth Patent, and, even more significantly, a question might be raised as to whether the plaintiff has established that the defendants' machine was infringing (in the sense of containing the two disputed features) on the comparatively infrequent occasions upon which Terence Haley used it. Looking at the evidence as a whole, but in particular at the fact that Terence Haley was involved with the use of the defendants' machine, and indeed in the business of putting it back into the van and thereafter covering it in tarpaulin when the plaintiff was seen looking at it and photographing it, at Bloody Oaks, I am satisfied both that Terence Haley was aware that, to put it broadly, there were aspects of the defendants' machine which probably infringed some right of the plaintiff, and that, at least at Bloody Oaks when Terence Haley was involved with the commercial use of the defendants' machine, he was using that machine at a time that it infringed, i.e. at a time when it had both the disputed features.

103. The fact that the plaintiff's claim on infringement succeeds against all the individual defendants (except Mrs Haley) is not quite an end of the matter. I must deal with Mr Platts-Mills's contention that there has been a common design whereby each of Joe, Richard and Terence Haley ("the Haleys") is liable for all the infringing acts of the corporate defendants, namely RR, HML and RRUK. The circumstances in which an individual shareholder or director of a company can be held liable for wrongs committed by the company is a difficult area of law, and I must confess to a little unease in deciding this point, because I was not referred to authority on the point by either counsel, and Mr Wilson did not really deal with the point, save to emphasise that any argument on this aspect against Terence Haley was much weaker than against Joe or Richard Haley, bearing in mind that Terence Haley ceased any involvement in the matter in about September 1996, and that he had not been involved in the day to day running of any of the defendant companies.

104. The argument that each of the Haleys is liable for torts committed by the corporate defendants is based on the following points, according to Mr Platts-Mills's argument. First, the Haleys regarded the corporate defendants as their creatures, moving business and assets from one company to the other as it suited them. Thus, Joe Haley agreed with the proposition put to him in cross-examination that "it does not really matter very much which company quotes for the business because it is all under the family control and you really do what you like". Secondly, when, in 1997, it became clear that RR was failing, it was HML which quoted for work which would have been done by RR, and Joe Haley, rather than RR, was responsible for lending the defendants' machine to HML, which effectively involved a diversion of business from RR. Thirdly, despite the fact that it was HML which took over from RR, it was RR that ordered materials including asphalt from Tarmac, who were not paid, even though HML was paid for the relevant job. Joe Haley accepted in cross-examination that, if that was the case, it was dishonest. Although Richard Haley tried to come up with a respectable explanation as to why this course was taken, I did not find it convincing. Fourthly, when the Haleys appreciated that liquidation of RR was starting to become inevitable, they changed the name of Griffin Industries Limited to RRUK. This appears to have been for the purpose of enabling the defendants to trade under the name "Relay Roads" despite the liquidation of RR. Fifthly, there is what Mr Platts-Mills justifiably described as "(at best) confusion" between different companies when the Haleys arranged a transfer of assets from RR to HML. The accounts of the two companies seem to suggest that a great bulk of assets were treated as being the exclusive property of each of the two companies at the same time.

105. It is a well established and cardinal principle of English Law that a company is a distinct person from the individual or individuals controlling or owning it, even where an individual is effectively the sole shareholder and the sole director. The Court should not be over ready to pierce the corporate veil, because it is well established that, save in special circumstances, the acts or defaults of a company are to be laid at the door of the company and not of individuals. However, there are circumstances where the Court is prepared to pierce the corporate veil or to treat the company as the agent of an individual, or to conclude that there was some sort of joint venture on the part of the company and an individual, and these are merely examples of the legal basis upon which an individual can be held liable for acts and/or defaults which are, on the face of it, the responsibility of the company. However, the mere fact that individuals owning and/or controlling a company have acted dishonestly and/or carelessly in certain transactions, the mere fact that they have not been nearly as careful as they should have been in identifying what property belonged to what company does not, to my mind, entitle the Court to hold that the individuals can be responsible for acts or defaults on the part of the company, particularly where the dishonesty or incompetence is in connection with matters which do not directly bear upon the default the subject of the relevant proceedings (in this case, of course, infringement of the Charlesworth Patent).

106. I accept that Joe, Richard and Terence Haley (in descending order of seriousness) have themselves infringed, and knowingly infringed, the Charlesworth Patent, and while each of them (again in descending order of significance) has not been a frank witness in these proceedings, and have been involved in the various matters Mr Platts-Mills relies on in relation to the mal administration of the various defendant companies. However, I do not consider that these matters are sufficient to justify my piercing the corporate veil or holding that any of the individual defendants were, as it were, "in it together" with the corporate defendants.

107. First, the mere fact that a company owned and controlled by an individual or family knowingly does something wrong, cannot without more render the individual or family liable for what the company has done, even though it can be said that the individual or family was in fact responsible for the company's acts and defaults. It seems to me that something more than being responsible for taking the decision to cause the company to act wrongly is required, and, at least in the absence of having been referred to authority to the contrary, I would have thought that the mere fact that the individual or family knew or suspected that what the company was doing was unlawful would be insufficient. Secondly, while the other matters raised by Mr Platts-Mills, show regrettable, even disreputable, action on the part of at least some of the Haleys, they do not seem to me ultimately to bear on the issue of whether or not any of the Haleys is liable for what are prima facie infringements by a corporate defendant of the Charlesworth Patent.

108. I should emphasise that this conclusion does not, of course, in any way cast doubt on my finding that each of the Haleys is liable to the plaintiff for infringement of the Charlesworth Patent by virtue of actually using the defendants' machine (in the case of Richard and Terence Haley) or (in the case of Joe Haley) designing, building and from time to time modifying the defendants' machine. All I am saying is that, in so far as the plaintiff is entitled to further relief against each of the corporate defendants, no member of the Haley family is liable to the plaintiff in respect of such relief.

109. As I mentioned, the defendants contend that the alleged invention disclosed by the Charlesworth Patent is obvious over two earlier patents, Cheney One and Cheney Two, and also over an alleged prior use. Cheney One is an Australian Patent, No 248,461, which was published on 6th December 1962; Cheney Two is an English Patent, No 1,066,320, published on 26th April 1967. The prior use relied on is based on the alleged use of a machine constructed in accordance with the teaching of Cheney One. In connection with the arguments on obviousness, it is right to remember that the plaintiff relies on Claims 1, 2 and 5 each having independent validity.

110. The specification is headed "Control Means for Concrete Laying and Packing Machines". In the description, Cheney One identifies two problems involved in "laying pipes or kerbings or the like", namely "variations in the forward speed of the machine" and "inconsistencies in the feed of concrete, aggregate or other material". The objective of Cheney One is a machine which lays consistent "pipes or kerbings or the like" by automatically varying the speed of the machine in response to variations in the quality of the concrete.

111. The description proceeds to explain the machine the subject of the claimed invention. The concrete is contained in a hopper, from which it is fed into a former (at the bottom of the hopper) which contains concrete packing means and a mandril surrounded by a helical blade; the mandril is driven by a mandril drive motor, and as a result the concrete is wormed from the hopper and extruded through the former. The description continues:

112. The description then goes on to explain that the pressure within the concrete being packed is transmitted through hydraulic cylinders to a throttle valve which is in a by pass circuit across a variable speed hydraulic motor (which is ultimately responsible for the wheel drive circuit) and the hydraulic fluid is supplied by a vane type pump driven by a petrol engine. Accordingly, the pressure in the mandril effectively controls or influences the throttle valve and, to quote again from the description:

113. The defendants contend that the alleged invention claimed by the Charlesworth Patent is obvious over Cheney One, because once one has the notion of linking the wheel drive motor to the pressure on the mandril in the former in a machine designed for extruding concrete kerb, it renders obvious the idea of controlling the wheel drive motor in a machine designed to lay asphalt kerb by reference to the pressure in the auger system of such a machine.

114. On behalf of the plaintiff, Mr Platts-Mills points out that Cheney One is concerned with concrete products, albeit including concrete kerb, whereas the Charlesworth Patent is concerned with asphalt kerb. As I have already indicated when considering the first issue of construction between the parties, this does not seem to me to be an answer of itself to the allegation of obviousness. However, as I see it, that does not mean that it is the end of the point: the question which I have to consider is one of fact. That question, as formulated by Mr Wilson, is whether it would have been obvious to convert a concrete kerb machine, such as Cheney One, so as to be able to extrude tarmac; Mr Platts-Mills puts the question slightly differently, namely whether the relevantly skilled man would regard Cheney One, a patent in respect of a concrete extruding machine, as being of interest in connection with the development of an asphalt machine.

115. In this connection, it appears to me that, in principle, the idea of converting a machine which extrudes concrete into one which extrudes asphalt is obvious. First, I consider that it is very significant that four different types of concrete kerb extruders were referred to in the evidence in this case, of which at least three were put to use so as to extrude asphalt. The predecessor to the Curb Cadet (the EC 1000 EconoCurber) has been used for asphalt in Saudi Arabia, albeit not particularly successfully, according to Mr Dan Willis, the Managing Director of Gomaco International. Secondly, the Curb Cadet itself has been so adapted. Again, Mr Willis said that, so adapted, the Curb Cadet was not particularly satisfactory, but Mr John Bowden, who as I have mentioned is an experienced engineer employed by Gomaco International, described the Curb Cadet as "working perfectly okay" with asphalt. Thirdly, a machine constructed in accordance with the teachings of Cheney One itself has been used in Australia for extruding asphalt kerb, according to Mr David Schumacher, the son in law of Mr Cheney, whose evidence will be dealt with more fully on the question of prior use. There was no reason to doubt Mr Schumacher's evidence, and I accept it. The only other concrete extruding machine referred to in these proceedings was one constructed in accordance with the teaching of Cheney Two, and there is nothing to suggest that it was used or adapted to extrude asphalt, but it is fair to say that there is nothing to suggest that it was not; the only witness who might have known was Mr Schumacher, whose knowledge of Cheney Two was much less than of Cheney One.

116. Secondly, the adaptations which would have to be made to a concrete extruding machine so as to enable it to extrude asphalt would be a change of mould (from a concrete mould to an asphalt mould), a source of heat for the mould and some insulation of the hopper, all of which Mr Willis accepted in evidence would be fairly obvious. The plaintiff himself accepted that there would be no significant difficulty in effecting a conversion of a concrete extruding kerb laying machine to an asphalt one. Thirdly, there is nothing in the expert evidence which I have heard to suggest that it would not be obvious to a relevantly skilled person to convert a concrete extruding machine so as to extrude tarmac. On the contrary: the expert evidence tended to support my conclusion.

117. However, that is not the end of the matter, because in my judgment, the question which I have to determine is slightly different from, and perhaps rather more specific than, the issue suggested by Mr Wilson. The question is more, as Mr Platts-Mills put it, whether the teaching in relation to a concrete extruding machine contained in Cheney One is something which the relevantly skilled person would have considered could obviously be converted so as to extrude asphalt in accordance with the allegedly inventive concept of the Charlesworth Patent. In this connection, the plaintiff's argument is that, mainly because of the rather different nature and properties of concrete and asphalt, there are a number of aspects of Cheney One, as a result of which it would not be obvious to the relevantly skilled person that it could be adapted or rendered applicable to an asphalt extruder along the lines of the alleged inventive concept of the Charlesworth Patent.

118. First, the plaintiff relies on the fact that there is no real risk of concrete seizing up or "bridging" in mid flow, as happens with asphalt. Thus, according to the teaching of the Charlesworth Patent, an asphalt extruder ideally should have "on/off", or "stop/start", control. As the description in Cheney One recognises, it is positively undesirable for a machine laying concrete kerb to stop at any time, as damage would be done to the product. This is well demonstrated by the fact that one of the expressed purposes of Cheney One is to prevent the machine stopping; the description states that "the inertia of the machine in stopping and starting introduces wide variations in pressure in the concrete being packed".

119. In his evidence, Mr Heron, the defendants' expert, confirmed that Cheney One was not interested in "stop/start and, indeed, that it indicated that stopping the run was an undesirable feature so far as a concrete extruding machine is concerned".

120. One of the central features of the teaching of the Charlesworth Patent is that (even if Claim 1 is not limited to this aspect) the wheel drive motor should stop as soon as the pressure in the auger motor drops, and the wheel drive motor should start as soon as the pressure in the auger circuit reaches a certain level. On the other hand, the teaching of Cheney One is not concerned with on/off control of the wheel drive circuit, but with altering the pressure in the wheel drive circuit so as to alter the speed of the machine laying the concrete kerb. However, as both the plaintiff himself, and the main expert called on his behalf, Mr Turton, accepted, the control mechanism taught by Cheney One would function in such a way that pressure had to build up in the mandril system before the wheel drive circuit was activated, and the machine started. The effect of their evidence was that, whereas a machine in accordance with the teaching of the Charlesworth Patent is "either running or stopped" (to quote the plaintiff himself) and the speed of the machine is determined by manual operation, the speed of a machine in accordance with the teaching of Cheney One is governed by the speed of the auger or mandril. In other words, to use the analogy advanced by the plaintiff, the control according to the teaching of the Charlesworth Patent is comparable to a light switch (in that it is either off or on) whereas its equivalent in the teaching of Cheney One is more like a dimmer.

121. It can be said with some force that a dimmer is not merely more sophisticated than a light switch, but that it contains the essential functions of a light switch and something in addition thereto. It seems to me that so far as this difference between the Charlesworth Patent and Cheney One is concerned, the effect of the control in the Charlesworth Patent is present in Cheney One, but although it is a feature of the essential inventive concept of Cheney One, it is more of a by product of that concept than a central feature of it, and Cheney One has no teaching in respect of it.

122. Secondly, the plaintiff contends that Cheney One works the wrong way round for asphalt. As Mr Wilson accepts, an asphalt extruder should ideally slow down as the asphalt gets cooler towards the end of the job: stiffer and cooler asphalt needs greater extruding pressure to compact it properly; however, on a given setting, Cheney One would go faster, not slower, with cooler, stiffer asphalt. The teaching of Cheney One is that increased pressure in the former should result in speeding up, whereas, if one is to have an asphalt extruding machine whose velocity varies by reference to auger pressure, it should speed up rather than slow down as that pressure increases. Of course, as I hope is clear from the discussion on the first point, this could be said not to be of the essence of the matter, because the Charlesworth Patent is not directed towards automatic control of the velocity of the machine, but to the "on/off" aspect. Nonetheless, it appears to me that there is some force in the contention that this second point identifies an aspect of Cheney One which might, as it were, deter or deflect a relevantly skilled person from thinking of using the teaching of Cheney One to arrive at the allegedly inventive concept in the Charlesworth Patent.

123. The plaintiff's third point is this. A problem with asphalt extruding machines, with which the Charlesworth Patent is concerned is, as I have mentioned, bridging or seizing up. Mr Platts-Mills contends that, by contrast, Cheney One is concerned with the problem of variations within a particular batch of concrete. However, for the defendants, Mr Wilson argues that Cheney One is directed towards problems or inconsistencies in the way in which the concrete is fed and, indeed, variations between different batches of concrete. In relation to this dispute, I agree with Mr Wilson: the relevant passages in the description in Cheney One (and in particular the words "inconsistencies in the feed of the concrete aggregate") are ambiguous, in that they could have either meaning, and the decisive factor is that, as appears to be agreed between the witnesses, Cheney One will not, even in theory, achieve its aim if the plaintiff's construction is correct, whereas it will, at least in theory, achieve its end if the defendants are right. Although that might not be appreciated by a layman reading Cheney One, I have little doubt that it would be appreciated by a conscientious person skilled in the relevant art in light both of the wording of the description, and of the circuit diagram in Cheney One. Since Cheney One is to be construed through the eyes of such a person, I believe that it must follow that the defendants' construction of this aspect of Cheney One is to be preferred. I therefore reject the plaintiff's third point: because of my conclusion on construction it takes one no further than the first point.

124. Fourthly, Mr Platts-Mills relies on the fact that the pressure in the concrete in Cheney One is sensed by the auger and is linked by a mechanical means to the drive of the machine: there is thus nothing in the control or link in Cheney One which involves sensing the hydraulic pressure in the auger drive, as in the Charlesworth Patent. This is true, but, while the teaching of Cheney One involves no direct sensing of pressure in the auger drive system, it does involve indirect sensing, as Mr Wilson says. A connected point made by Mr Platts-Mills is that the way in which the link by mechanical means works would require the mandril to move, at least to an extent, laterally as well as horizontally in relation to the tubing in which it is located. That seems to me to be right, as does the consequence for which Mr Platts-Mills contends, namely that the proximity of the tube, particularly if the mandril is fairly closely confined (as the defendants contend), will effect the perceived pressure on the mandril, and, as a result, the efficacy of the linking system would be detrimentally affected. The combination of these two factors relating to the linking seems to me to be of some significance on the issue of obviousness.

125. Fifthly, the plaintiff contends that Cheney One was primarily, or at least to a substantial extent, concerned with the production of concrete pipes, rather than concrete kerbs. There is force in that point in that the figures of Cheney One suggest that it is directed more to pipes than kerbs, but it is clear from the description, and indeed the claims, that it is intended to extend to kerbs as well as pipes, and there is nothing in the wording of Cheney One, or in the expert evidence which I have heard, which casts doubt on that conclusion.

126. Sixthly, it was contended on behalf of the plaintiff that the mandril contemplated by Cheney One was not really equivalent to the extruding auger envisaged by the Charlesworth Patent. This contention was based on the fact that the relevant illustrative figure in Cheney One did not show a confined auger and that Cheney One would not have been concerned to teach the use of a confined auger bearing in mind the way in which the machine it contemplates is operated, and also the purpose of that machine. It appears to me that the mandril, with its surrounding helical blade, must enjoy a degree of confinement, because, as Mr Wilson points out, there would otherwise be no build up of pressure.

128. It appears to me that the four factors which I consider can be relied on by the plaintiff between them provide a real basis for his contention that the Charlesworth Patent was not obvious in the light of Cheney One. Whether, taken together, these four factors ultimately justify his argument is something which I will consider in the last section of this part of my judgment, not least because it appears more sensible to reach a conclusion on obviousness over Cheney One, after I have discussed the alleged prior use, which is said to involve a machine designed and constructed in accordance with the teaching of Cheney One.

129. It is right to record the fact that Cheney One was built for use on rails. As I understood his argument, Mr Platts-Mills does not contend that he is assisted in his argument against obviousness on the ground that there could be said to be invention in substituting two-wheel drive, given, perhaps, that the machine was to be used on smoother ground than may have been envisaged by the inventor of Cheney One. It is right to say that, had he so argued, I would have rejected that contention.

130. The specification is headed "Improvements in Concrete Laying Machines", but when identifying the problems to which it is directed, the description makes reference to the problem:

131. The description goes on to explain that "the main object" of the claimed invention is "to provide a means for uniformly compacting substances which may vary in their flow characteristics so that the density of the extruded product is more nearly uniform than with the same product extruded by constant speed constant drive machines...". The description proceeds:

132. Such a machine is then described as having:

133. The description goes on to say:

(In each of the quotations from the description of Cheney Two, the emphasis is added).

134. There are four figures included in Cheney Two. The first is a plan view of the vehicle and concrete extruder, including the drive arrangement, the second and third figures are not particularly important for the purpose of these proceedings, and the fourth figure shows a somewhat complex hydraulic circuit.

135. One of the issues which it is, I believe, convenient to get out of the way at once, is whether Cheney Two is concerned with concrete extrusion only, as the plaintiff contends, or whether it is also aimed at extrusion of other materials, and in particular those identified in the first passage I have quoted from the description, which, of course, include bitumen, as the defendants argue. In my judgment, the plaintiff's contention on this point is correct. While it is true that there is reference to other materials, it seems tolerably clear, even from the limited passages which I have quoted from the description, that the claimed invention is directed towards concrete extruders, and not extruders of other materials. In my judgment, on a fair reading of Cheney Two, there is no teaching as to how a machine which is intended to extrude material other than concrete is to be designed, constructed or used. This point is underlined by the evidence, which I accept, that the various materials referred to in the initial passage I have quoted from the description have different characteristics, which would have been appreciated by the relevantly informed reader.

136. However, as already indicated when considering Cheney One, the fact that a patent is concerned with a concrete extruding machine does not appear to me, either as a matter of principle, or as a matter of fact in light of the evidence in the present case, of itself to provide the plaintiff with an argument which must defeat the defendants' case on obviousness in so far as it relies on Cheney Two.

137. As with Cheney One, the rejection of the plaintiff's argument so far does not mean that the defendants succeed on obviousness. As with Cheney One, it is necessary to consider whether the teaching in relation to a concrete extruding machine contained in Cheney Two is something which the relevantly skilled person would have considered could obviously be adapted so as to extrude asphalt in accordance with the allegedly inventive concept of the Charlesworth Patent. Not surprisingly, it appears to me that at least some of the points which Mr Platts-Mills is able to raise to support his argument against obviousness in relation to Cheney One also apply in relation to Cheney Two.

138. Thus, the plaintiff's first argument on Cheney One also applies to Cheney Two: the teaching of the Charlesworth Patent that, an asphalt extruder should have stop/start control is rather different from the teaching of Cheney Two, which, like Cheney One, is concerned with variable speed. However, a machine designed in accordance with the teaching of Cheney Two, as it appears to me, would, like a machine designed in accordance with the teaching of Cheney One, start moving once a certain pressure has been reached, and would come to a halt once the pressure goes below a certain level. It is fair to say that the oral evidence on this point in relation to Cheney Two was not quite as extensive as in relation to Cheney One, but it does appear to me that this conclusion is supported not only by the evidence but also by logic. It seems to me that on this point, in fact, the plaintiff's case is slightly weaker on Cheney Two than on Cheney One. So far as stopping is concerned, when describing the hydraulic circuits, the description in Cheney Two states that the effect of the valves is intended "to ensure quick deceleration but slow acceleration of the forward travel motor"; further, unlike in Cheney One, there is nothing in Cheney Two which suggests in terms that a "stop/start" feature would be unattractive on a concrete extruding machine.

139. The second point of distinction validly relied on by Mr Platts-Mills in relation to Cheney One applies equally to Cheney Two: the stiffer the asphalt, the faster a machine, designed in accordance of the teaching of Cheney Two, would go, whereas an asphalt extruding machine should go slower in such circumstances.

140. I do not find it easy to decide whether the third point of distinction alleged on behalf of the plaintiff (albeit unsuccessfully) between Cheney One and the Charlesworth Patent exists as between Cheney Two and the Charlesworth Patent. It will be recalled that, so far as Cheney One was concerned, I decided that, in agreement with the defendants, that Cheney One was not concerned with detecting changes within a particular batch of concrete, and this was essentially on the basis that the language of the relevant passages in the description was ambiguous, and that the conclusive factor was that the circuit contained and described in Cheney One would have been perceived by the relevantly skilled reader not to achieve its end, even in theory, on the plaintiff's construction. To my mind, the same very important point may be made in relation to Cheney Two: although Mr Platts-Mills initially suggested otherwise in his closing submission, he was, I think, eventually constrained to accept that, if Cheney Two was intended to work so as to change the speed of the machine to reflect changes in the density of a particular batch of concrete, it effectively worked the wrong way round. In my judgment, he was correct to make that concession which was accepted by the plaintiff's own expert, Mr Turton. Given that one is here concerned with a patent, a document intended to have practical effect, and one is to construe it by reference to how it would be read by a person, skilled in the relevant art as at the priority date this point factor is clearly very important: indeed, as already indicated, I regarded it as decisive when trying to resolve a very similar issue of construction on Cheney One.

142. My conclusions as to the proper construction of Cheney Two on this issue means that on this aspect there is a greater difference between Cheney Two and the Charlesworth Patent than between Cheney One and the Charlesworth Patent: Cheney Two, as I see it, is concerned with slowing down and speeding up during a particular run, to reflect changes in the consistency of the concrete.

143. The fourth distinction relied on by the plaintiff as distinguishing Cheney One from the Charlesworth Patent does not apply as between Cheney Two and the Charlesworth Patent. Cheney Two envisages two hydraulic circuits, control being effected on one (the wheel drive circuit) by a hydraulic system which senses the pressure in another system. I express that slightly cagily, because it is necessary to consider a further distinction between Cheney Two and the Charlesworth Patent advanced on behalf of the plaintiff. As Cheney One included an auger or mandril to effect extrusion, Mr Wilson was able successfully to contend that Cheney One envisaged an extrusion machine with pressure sensed in the auger system, somewhat not unlike the teaching of the Charlesworth Patent. However, there is no express reference to there being an auger or anything like an auger in Cheney Two. In those circumstances, Mr Platts-Mills contends that Cheney Two is not concerned with concrete kerbing effected by extrusion, but with concrete kerbing effected by slip forming.

144. Like many points of construction relating to the two Cheney Patents, I do not find this easy to resolve, but I have reached the conclusion that the plaintiff's argument on this point is correct. It is quite true that Cheney Two refers throughout to "extrusion" and nowhere uses the expression "slip forming". However, although a somewhat loose use of the word, it does not seem to me that "extrusion" mis-describes forcing out concrete in a shape of a kerb by means of gravitational force, as opposed to an additional force, such as that supplied by an auger. Having reached that conclusion, as a matter of ordinary language, I draw some comfort from an Australian patent, No 103628, referred to by Mr Turton in his evidence (and not, in the event, otherwise relevant to the issues between the parties as they have developed) which was published before any of the patents to which I have so far referred. This earlier Australian patent undoubtedly referred to a slip former, and yet it extensively used the word "extrusion" to define the process. It should be emphasised that I am referring to this earlier Australian patent not so much as an aid to the construction of Cheney Two, but more to confirm my agreement with the plaintiff's case that, at any rate 30 or 40 years ago, a machine which manufactured kerb by slip forming could properly be described as "extruding", at least where it was not being used in contradistinction to a machine which works by extruding in the narrower sense, such as a machine which is clearly intended to be used for asphalt.

145. No reference is made anywhere in the description or the claims of Cheney Two, or in the figures of Cheney Two, to any sort of auger, screw or mandril. It is true that the defendants produced a drawing during the currency of their evidence showing how a confined auger could be included in the type of machine contemplated by Cheney Two, but it appeared to me to involve adding a whole aspect to Cheney Two which is conspicuous by its absence, both in the description and in the figures of Cheney Two, namely a compaction tube with an auger confined within it, and situated between the hopper and the mould. In the absence of clear words requiring the implied inclusion of these features, I do not consider it legitimate to treat them as included, which is what Mr Wilson's argument on behalf of the defendants requires. The fact that Cheney Two envisages a mould which is vibrated, and which has fluting on it, appears to me mildly to reinforce the plaintiff's argument that the Patent is concerned with slip forming and not with extrusion in its narrow sense. The plaintiff's case is also supported by the fact that concrete kerbing is normally effected by slip forming, although it can be effected by extrusion in the narrow sense, and, as already indicated, I consider that Cheney Two is concerned with concrete, and not with other materials. Some further support for this conclusion is to be found from the fact that Cheney Two appears to contemplate "extruding" concrete with as much as a three inch slump, which, as I understand it, could only be done by slip forming and not by extrusion in the narrow sense.

146. Given my conclusion on this last point relating to Cheney Two, it might be thought that I should revise the conclusion I reached on the plaintiff's fourth point on Cheney One. However, I do not think that would be appropriate. First, of course, there is the basic point that Cheney Two cannot possibly be invoked to assist the construction of Cheney One (indeed, as I see it, it could not be so invoked even if it pre-dated Cheney One, but the fact that it post-dates Cheney One must be conclusive). Quite apart from this, it is right to recall two relevant points of distinction between Cheney One and Cheney Two. First, both the description and the figures of Cheney One make it clear that there is an auger in what, at least on the face of it, appears to be some sort of compaction area, whereas, of course, Cheney Two does not. Secondly, Cheney One is concerned with concrete pipes as well as concrete kerb, whereas Cheney Two is only concerned with concrete kerb. There is therefore good reason for the inclusion of an auger in Cheney One, although it is fair to add that this reason provides the basis upon which Mr Platts-Mills is able to argue that that auger is not there for the purpose of extrusion in the narrow sense, but for the purpose of effectively shaping the pipes.

147. It is right to mention that there was considerable debate, both in evidence and in argument, as to the nature and purpose of a certain feature of Cheney Two, namely "helical packing means", which are directly coupled to hydraulic extruder motors, and which themselves "depend into the hopper". I must confess to considerable confusion and uncertainty as to what these features are intended to do or be. In the end, it seems to me that it would add unnecessarily to what is already a lengthy judgment if I discuss the arguments in any detail. Each party was able to come up with an explanation for these features upon which the other party was able to pour a certain amount of justified doubt, which, at times, even verged on scorn. I was not particularly convinced by either of the explanations: ultimately, I am left in such uncertainty as to the nature and purpose of these "helical packing means" as to conclude that they simply do not assist on any of the questions of construction, and that one is really better off deciding what they are, if one can, after determining the issues of construction free of such input into the argument as might be achieved from the contest as to the meaning of "helical packing means", which arguments merely served to cloud the debate on the questions of construction rather than to assist them.

148. Cheney Two was constructed on a Land Rover chassis, but I did not understand Mr Platts-Mills to contend that there was invention in the idea of building Cheney Two on a purpose built chassis and using the consequent hydraulic drive to power two separate wheels as is involved in the Charlesworth Patent. It is right to record that if Mr Platts-Mills had so argued, I would have rejected that contention.

149. As I have mentioned, I heard evidence from Mr David Schumacher, who is the son-in-law of Mr Cheney, relating to prior use. He gave his evidence through video link from Australia, and, at least as far as it went, I found his evidence clear and convincing. He recalled a machine designed and constructed effectively in accordance with the teaching of Cheney One, with which he was familiar. Its basic principle, he said, "was to extrude concrete by monitoring the pressure exerted on the concrete by an auger... the concrete [being compressed by an auger] into a compression chamber... from [which] it was extruded into a mould". He explained that "the pressure was varied according to the slump mix" and that such pressure "had to be adjusted for each particular mix" and that "monitoring a forward movement of the machine through a hydraulic motor and a control valve". The machine he described, if I understood his evidence correctly, accorded with the teaching of Cheney One, at least as I have construed it. The only feature which, according to him, the machine had over and above the description in Cheney One was a vibrator which does not, I think, take matters any further so far as the issues in this case are concerned.

150. There is no doubt that the machine described by Mr Schumacher (which I shall call "the Cheney machine") was designed, and used for concrete kerb. As I understand it, at least at the time to which Mr Schumacher's evidence relates, the Australian Highways Department required its kerbs to be made of concrete, and asphalt was only used for temporary kerbing. The Department, according to Mr Schumacher, asked Mr Cheney whether the Cheney machine would extrude asphalt, and in practice it did so "quite satisfactorily". It appears to me, from the evidence of Mr Schumacher and from inspecting the photographs, that at least one of the photographs taken of the Cheney machine at work shows it laying asphalt. The extent to which the Cheney machine was used for laying asphalt is not clear from Mr Schumacher's evidence, but I am satisfied that it was used for that purpose, and tolerably successfully so used on at least one occasion. I should also add that, while Mr Schumacher's evidence satisfies me that a machine was also constructed which was at least to some extent in accordance with the teaching of Cheney Two, rather than Cheney One, he has no real recollection of it (and indeed may not have had much, if any, experience of it); he was unable to say whether or not it was ever used for laying asphalt, albeit that he was able to say that it was definitely used for laying concrete.

151. There was no suggestion of the Cheney machine, when being used to lay asphalt kerb, any more than when being used to lay concrete kerb, being operated in secret. Indeed, there are photographs showing the Cheney machine, albeit when laying concrete kerb, being inspected by various dignitaries, including the then-Prime Minister of South Australia.

152. The defendants have not provided particulars which would be expected in relation to a prior use claim, pursuant to the provisions of RSC Order 104 Rule 6(3). Indeed, Mr Schumacher did not actually say in terms when he recalls the Cheney machine being used. If one confines oneself to the transcript of his evidence, it could have been after the priority date claimed by the Charlesworth Patent. I am not quite clear whether Mr Platts-Mills specifically took that point, although he did mention that Mr Schumacher's evidence did lack particulars with regard to dates. Mr Wilson's argument seems to have proceeded on the assumption that, if I accepted Mr Schumacher's evidence (which I do), he was referring to the use of the Cheney machine for asphalt prior to November 1962. The evidence does indicate that the use of the Cheney machine for laying asphalt kerb in Australia was after the priority date claimed by Cheney One.

153. In my judgment, the evidence establishes that the Cheney machine was used in public for the laying of asphalt, and that it was used in a way which would have enabled a relevantly skilled person to appreciate how it was working. First, the use was in public, as I have mentioned. Secondly, it is clear from the evidence of Mr Schumacher (supported by at least one photograph) that members of the public were in fact permitted to look at the workings of the Cheney machine. I have in mind the evidence that the then-Prime Minister of South Australia inspected the workings of the Cheney machine. It is fair to say that there is no evidence to suggest that he asked, or was given the opportunity, to inspect the circuits within the machine, but equally there is no reason to think that, if he had asked to inspect the circuits, he would have been refused the opportunity. If, as seems likely, the use of the Cheney machine for laying asphalt kerb was after the priority date claimed by Cheney One, there is no reason to think that Mr Cheney, or any of his associates, would have had any reason to be secretive about the way in which the Cheney machine worked. Indeed, as I have mentioned, the evidence suggests that Mr Cheney was rather proud of the use being made of his machine, and was quite happy to have anyone inspect it.

154. In my judgment, the defendants' case on prior use, relying as it does on Mr Schumacher's evidence, does not seem to me to take matters much further forward on the question of obviousness, given my conclusion that it would have been appreciated, by the relevantly skilled person reading Cheney One, that a machine designed and constructed in accordance with its teaching could be used for laying asphalt kerb. All that the prior use which the defendants establish through the evidence of Mr Schumacher does is to make that argument good on the basis of prior use as well. There is no evidence to suggest that, when laying asphalt, the Cheney machine was set so as to have "on/off" control appropriate for asphalt, or even that it was capable of being set to an appropriate setting. There is no evidence that it was capable of sufficiently abrupt stopping to avoid the laying of poor asphalt when bridging or other gaps in the supply of asphalt occurred, in accordance with the teaching of the Charlesworth Patent. In particular, Mr Schumacher said nothing to suggest that the Cheney machine laid asphalt kerb more efficiently than asphalt extrusion machines in the UK.

155. I must confess to real difficulty in determining whether the allegedly inventive concept in the Charlesworth Patent was obvious over Cheney One, Cheney Two or the prior use, which has just been discussed. The difficulty is, I think, partly attributable to the fact that the issue is quite near the line, but also to the fact that the expert evidence on obviousness was ultimately not directed as much as it should have been to the essential issue. Instead of concentrating on the question of whether, on certain alternative assumptions as to the way in which a machine designed in accordance with Cheney One or Cheney Two worked or would work, the Charlesworth Patent was obvious over Cheney One or Cheney Two, the expert evidence on the question of obviousness concentrated almost exclusively on the how a machine constructed and designed in accordance with Cheney One or Cheney Two would operate, and, indeed, what Cheney One and Cheney Two meant.

157. I have reached the conclusion that Claim 5 of the Charlesworth Patent was not obvious over Cheney One or Cheney Two or, indeed, over the prior disclosure established on Mr Schumacher's evidence.

159. There are various factors in this case which tend to point towards the conclusion I have indicated, namely that the allegedly inventive aspects of the Charlesworth Patent are indeed inventive over Cheney One and Cheney Two. First, there is the fact that the onus of proof on obviousness lies on the defendants. I do not need to decide the issue on obviousness on this ground, but it seems to me that the issue is close enough to the line to merit reference to this fact.

160. Secondly, there is the fact that Mr Turton, the plaintiff's expert, took the view that the Charlesworth Patent was not obvious. It would be wrong to place a great deal of weight on this, because his conclusion that the Charlesworth Patent was not obvious over Cheney One or over Cheney Two was in each case based on reasons, some of which I have rejected when considering Cheney One and Cheney Two in the earlier sections of this part of my judgment. However, I am concerned with the question of whether Cheney One or Cheney Two would have led the relevantly skilled person to the Charlesworth Patent. While I may not wholly agree with Mr Turton's reading of Cheney One or Cheney Two, he was relevantly skilled, he was honest, and he did not think the Charlesworth Patent obvious over them on his interpretation, which was not an unreasonable one.

161. In his evidence in chief, Mr Heron, the defendants' expert witness, took the opposite view, namely that the Charlesworth Patent was obvious over Cheney One and over Cheney Two, but his expression of opinion similarly suffered from the fact that I have rejected some of the reasons underlying his view. So far as anything remains of the respective conclusions of Mr Turton and Mr Heron on this point, I was more impressed by the evidence of Mr Turton. In giving his evidence on this aspect of the case, namely obviousness, he struck me as better informed and more considered than Mr Heron; furthermore, when dealing with infringement, Mr Heron was not, at any rate in relation to this case, been as thorough and careful as he might have been. In making that observation, it is only fair to Mr Heron to add that I strongly suspect that he was placed in a difficult position by having clients who are not prepared to give him the assistance, from their own experience and knowledge, which he might have expected; Mr Turton, on the other hand, has the benefit of the plaintiff's own experience, and I have no reason to think that any assistance he wanted from the plaintiff was given other than in a fair way.

162. A third factor, which to my mind has some real value, is the commercial success which has been enjoyed by the Charlesworth machine since its introduction into this country, coupled with the evidence that the Charlesworth machine was regarded as a real advance on what had gone before.

163. There is no doubt that the Charlesworth machine has enjoyed substantial commercial success in this country. However, the defendants point out that, while the plaintiff has produced pretty detailed evidence showing the extent to which the Charlesworth machine has penetrated, indeed almost taken over, the relevant market in the years following its introduction in 1983, the plaintiff has produced no significant evidence as to the extent to which he and Extrudakerb had penetrated the market with their earlier machines. The evidence of Mr John Armitage, who works for the Tarmac Plc Group of companies, was that, at least in the North East of England, the plaintiff and his company had a very substantial proportion of the market before 1983 and the introduction of the Charlesworth machine. I have no reason to think that the position was very different in the rest of the country. While a significant point for the defendants, it does not seem to me that this conclusion wholly disposes of any reliance which the plaintiff can place on the commercial success of the Charlesworth machine in supporting his claim to inventiveness. Even assuming that the plaintiff enjoyed the same very high proportion of the market for asphalt kerb extruders before the introduction of the Charlesworth machine as he did thereafter, it nonetheless seems clear that both he and the market took the view that the Charlesworth machine was an improvement on its predecessor: otherwise, it is hard to see why it effectively drove its predecessor out of the market. Of course, it is conceivable that the plaintiff decided that, even though the Charlesworth machine did not represent a significant improvement, it was for some reason in his own interest to ensure that it took over the market. However, it is a little difficult to believe that, unless the plaintiff reasonably considered that the Charlesworth machine was a significant improvement on what went before, and the market agreed with him, the Charlesworth machine would have become so successful.

164. This conclusion is also supported by the fact that not only the plaintiff, but also Mr Armitage considered that the Charlesworth machine represented a major breakthrough. In his witness statement (and I accept that one must make some allowance for the fact that it was prepared by the plaintiff's solicitors) Mr Armitage said:

165. It is right to add that these observations were made in the context of his earlier evidence to the effect that asphalt kerb extruding machines in use prior to this "could not be relied upon to lay consistently good kerb on a regular basis" and "were slow and unreliable" which he described as "being common knowledge" within the industry.

166. No real doubt was cast on this evidence in Mr Armitage's evidence in cross-examination. I suppose that it could be said that, albeit to a limited extent, he was not entirely objective, because he (and his immediate superior in the Tarmac Group at the time) appear to have been involved in discussions with the plaintiff in connection with the development of the idea behind the Charlesworth Patent. Having said that, Mr Armitage struck me as a fair and honest witness, and there is no reason to doubt the evidence he gave, particularly as it was entirely consistent with that of Mr Willis, who it may be recalled is employed by Gomaco. He also said that he had been very impressed by the Charlesworth machine, and, once again, there is no reason to doubt either his honesty or his qualifications to give such evidence. Even less than Mr Armitage can it be said that Mr Willis is in some way involved in the success of the Charlesworth machine.

167. A further, rather different, factor relied on by Mr Wilson for calling into question the significance of the commercial success of the Charlesworth machine on the issue of obviousness is the nature of the prior art and prior use relied on by the defendants. So far as Cheney One is concerned, he points out that it was an Australian patent, and that there is no evidence as to the conditions or needs in Australia, save that it is clear that, at least at the time that Cheney One was published, and it would appear for some time thereafter, asphalt was only used for temporary kerbing, according to Mr Schumacher. In those circumstances, it may be that the Australian market was perfectly content with an asphalt laying machine constructed in accordance with the teaching of Cheney One (or, indeed, Cheney Two, which appears to have been registered in Australia as well as in the United Kingdom) and that there was no need or requirement for a further refinement along the lines of the Charlesworth machine. Further, he suggests that there is no reason to think that anybody in Australia would have thought of, as it were, exporting the idea of Cheney One into the United Kingdom, nor any reason for a person skilled or interested in the relevant art to search the Australian Patent Office.

168. In relation to Cheney One, that argument obviously has some force, albeit that it is rather difficult to assess the extent of that force in the absence of any evidence either way. However, it is rather less easy to accept the force of the argument in relation to Cheney Two, which is, of course, a United Kingdom registered patent. In that connection, it seems to me that Mr Platts-Mills made a fair point when he said that, if the Charlesworth Patent is obvious over Cheney Two, there is no reason why large contractors, including Tarmac, would not have investigated the possibility of using or adapting Cheney Two so as to enable it to produce a satisfactory asphalt extruding machine to lay kerb in accordance with the allegedly inventive concept of the Charlesworth Patent.

169. All in all, I consider that the commercial success argument, although not overwhelmingly powerful, has certainly not been destroyed by the various points raised by Mr Wilson, and that it does provide real support for the plaintiff's case, and indeed for my conclusion, on the issue of obviousness.

170. Fourthly, there is the fact that, as I find, Joe Haley, an experienced and talented, if not a qualified, engineer in the relevant field, who had designed and made an asphalt extruder, both failed to think of or include in that asphalt extruder the device claimed to be the inventive feature of the Charlesworth Patent, and, after discovering the existence and nature of the Charlesworth machine, copied that idea. In this connection, Mr Willis of Gomaco said that he delivered a Curb Cadet pursuant to an order given by RR, and, shortly after, he received an angry telephone call from Joe Haley who had essentially two complaints. The first was that the Curb Cadet did not seem to work well with asphalt, and the second was that the machine had no connection between the wheel drive circuit and the auger drive circuit. Mr Willis said that he informed Mr Haley not only that the Curb Cadet was not designed to take asphalt, but also that only the asphalt extruders made by Extrudakerb had the connection referred to by Joe Haley, and that this was the subject of a patent. Indeed, consistent with his evidence, Mr Willis informed Joe Haley that the Charlesworth machine "was the only asphalt machine capable of extruding satisfactory asphalt on a consistent basis". There was a degree of dispute between Mr Willis and Joe Haley as to what was said in the conversation, but I am quite satisfied that Mr Willis's evidence is to be preferred. He was an honest witness with no reason for any bias, whereas I am, unfortunately, unable to make the same finding about Joe Haley. What I think happened was that, as a result of this conversation, Joe Haley was made aware that there was a machine with the necessary connection, which was protected by a patent, and which he then proceeded to follow when he designed and constructed the defendants' machine.

171. A further point which I believe tends to support my conclusion on obviousness, at least so far as prior art is concerned, is that, as I have already indicated, Cheney One and Cheney Two appear to me to be very difficult to interpret: the discussion earlier in this judgment relating to those two patents should, I hope, indicate my reasons for that conclusion. In my judgment, where, as here, the Court is satisfied that an item of prior art, over which the patent in suit is alleged to be obvious, is difficult to interpret or understand, even if viewed through the eyes of the appropriately skilled person, I consider, in agreement with Mr Platts-Mills, that this is a factor which tends to tell against the argument of obviousness. It is not a factor which is normally likely to be decisive, and in many circumstances it may not even be of much weight. In the present case, however, it seems to me that Cheney One is unclear in some respects, and in some ways Cheney Two is even more difficult to understand, and, indeed, in one important feature its teaching is actually wrong.

172. For these reasons, I reach the conclusion that the attack on Claim 5 of the Charlesworth Patent based on obviousness, whether over Cheney One, over Cheney Two, or over prior use, fails.

173. Although I conclude that Claim 5 of the Charlesworth Patent is valid, it is still necessary to consider whether Claim 1 and Claim 2 (given that it is contended by Mr Platts-Mills to have separate validity) are valid. In light of my view as to the proper construction of Claim 1, and in particular of the word "controlled", of the four grounds relied on by the plaintiff for justifying that Claim 5 was not obvious over Cheney One or Cheney Two, the first (which is the same in each case) does not apply: Claim 1 is not, in my judgment, simply concerned with "on/off" whereas, at least in my view, Claim 5 is so concerned. Further, as I see it, the fourth ground relied on by the plaintiff as distinguishing Cheney One from the Charlesworth Patent is rather stronger in relation to Claim 5 than in relation to Claim 1.

174. Quite apart from this, the other factors which have served to persuade me to find in favour of the plaintiff on obviousness so far as Claim 5 is concerned appear to me to be rather weaker in relation to Claim 1. In particular, the views of Mr Turton, and the evidence that the Charlesworth machine was a commercial success and regarded as a breakthrough appear to me to relate in particular to the more limited control feature in Claim 5 as opposed to the more general one in Claim 1. In these circumstances, I have reached the conclusion that, while the defendants have not established that Claim 5 is obvious, they do succeed on Claim 1. I see no reason for holding that Claim 2 has independent validity over Claim 1, and therefore the defendants succeed on Claims 1 and 2.

175. In these circumstances, I conclude that Claim 5 of the Charlesworth Patent is valid, and that it was infringed by the defendants' machine, but that Claims 1 and 2 were invalid on grounds of obviousness. The plaintiff, Mr Charlesworth, is entitled to relief against all the various defendants, except the third defendant, Mrs Valerie Haley, against whom he has effectively discontinued in any event. If counsel are unable to agree the precise form of the order and the nature of the relief to be accorded against each of the defendants, I will hear further argument.