Case No: CO/426/2003
Neutral Citation No [2003] EWHC 2003 (Admin)
IN THE HIGH COURT OF JUSTICE
QUEENS BENCH DIVISION
ADMINISTRATIVE COURT                                                                
Royal Courts of Justice
Strand, 
London, WC2A 2LL

Wednesday 1 October 2003
Before :

THE HONOURABLE MR JUSTICE RICHARDS

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Between :

	ROBERT FIDLER	Appellant	
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	(1) FIRST SECRETARY OF STATE
(2) REIGATE AND BANSTEAD BOROUGH COUNCIL	Respondents	

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(Transcript of the Handed Down Judgment of
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Mr Jonathan Clay (instructed by DMH (Solicitors)) for the Appellant
Mr Timothy Mould (instructed by the Treasury Solicitor) for the First Respondent

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Judgment

Mr Justice Richards: 
1.	These proceedings under ss.288 and 289 of the Town and Country Planning Act 1990 concern a former farmyard and adjacent land at Honeycrock Farm, Salfords, Surrey, which is owned by the appellant, Mr Fidler.  The site includes a number of buildings (units 1 to 8) grouped around a southern yard and two attached steel-framed barns (units 9 and 10) in a northern yard. It is not in issue that there are now three planning units on the site:  planning unit A comprising units 1 and 2 in the south west corner, planning unit B comprising essentially agricultural land at the northern end, and planning unit C comprising the balance of the site, including units 3-10 and the southern and northern yards. 
2.	The site has been the subject of a number of enforcement notices issued by the local planning authority, Reigate and Banstead Council.  Those of most immediate relevance were issued between January 2001 and February 2002 and are referred to as Notices A to G and Notice I.   
3.	The first of the notices chronologically was Notice G, which was issued on 4 January 2001 and related to the reconstruction of the roof of unit 7.   
4.	The appellant then applied on 22 January 2001 for a certificate of lawful existing use or development under s.191 of the Act in relation to various uses of the site, contending that there had been a deemed grant of planning permission by under-enforcement under s.173(11) of the Act and that in any case there had been 10 years continuous use of the land for mixed commercial uses.  
5.	The council did not determine that application, but instead issued Notices A-F on 7 March 2001, alleging a variety of breaches of planning control.
6.	All the enforcement notices were appealed under s.174 of the Act, and the deemed refusal (through non-determination) of the application for a certificate of lawful development was appealed under s.195.  
7.	The First Secretary of State appointed an inspector, Mr DE Morden, to determine all the appeals.  A public inquiry opened on 22 January 2002 but was adjourned after 4 days so that the inspector could make preliminary findings as to the validity of certain of the enforcement notices and on other legal submissions made by the parties.  His preliminary findings were issued on 26 February 2002 and included findings that Notices B, D and E, which alleged various changes of use on the site, were invalid and could not be corrected without injustice to the appellant.
8.	Meanwhile the council had issued a further enforcement notice, Notice I, on 4 February 2002, again alleging, though in different terms, a material change of use of the site.  An appeal against that notice was dealt with together with the existing appeals.  The resumed inquiry in relation to all the appeals was held in May 2002.
9.	The inspector's decision letter was issued on 17 December 2002.  It extended to over 30 pages plus appendices (including details of the appeals at appendix 1 and his preliminary findings at appendix 2).  The inspector allowed the appeals in relation to Notices B, C, D, E, F and G and quashed those notices.  In respect of Notice A he dismissed the appeal under ground (a) of s.174(2); he stated that the appeal under ground (b) had been withdrawn, though whether that was correct is in issue.  He corrected and varied Notice I so as to include a substituted description of the uses alleged to be in breach, a substituted statement of the remedial action required, and a period of 12 months rather than 6 months for compliance.  He then dismissed the appeal against Notice I except to the extent of permitting certain uses of units 6,7 and 8.  He allowed to a limited extent the appeal in respect of the certificate of lawful development, which he described as Appeal H, and granted a certificate relating to certain limited uses; but the main part of the appellant's case on the appeal failed together with the substantial dismissal of the appeal against Notice I.
10.	The appellant now appeals to this court under s.289 of the Act against the inspector's decision to uphold Notices A and I.  He also applies under s.288 to challenge that part of the decision in which the inspector found against the appellant on the application for a certificate of lawful development.
11.	The main issues raised before this court are: (1) whether the inspector was entitled to find that Notice I was a valid "second bite" notice within s.171B(4)(b) of the Act ("the second bite issue"); (2) whether he erred in finding that there had been a material change of use of the land ("the material change of use issue"); (3) whether he erred in relation to the question whether  various commercial uses of the site had been carried on long enough to become lawful ("the previously established lawful use issue"); (4) whether he erred in various respects in his dismissal of the appeal against Notice A ("the Notice A appeal issue"); (5) whether he erred in his rejection of the appellant's case that the combined effect of s.173(11) of the Act and an enforcement notice issued by the council in 1996 had been to confer deemed planning permission on uses that the notice did not require to cease ("the deemed planning permission issue").  Various other matters raised in the appellant's written or oral submissions can be dealt with, so far as necessary, when considering those main issues.
12.	The argument before me has been between the appellant and the First Secretary of State.  The council was not represented at the hearing.
Statutory framework
13.	Part III of the 1990 Act is concerned with control over development.  By s.55(1), “development” means the carrying out of building, engineering, mining or other operations in, on, over or under land, or the making of any material change in the use of any buildings or other land.  By s.55(2), however, certain operations or uses of land are not to be taken to involve development.  That includes, under s.55(2)(a), certain works of maintenance, improvement or alteration which (i) affect only the interior of the building or (ii) do not materially affect the external appearance of the building.  It also includes, under s.55(2)(f), in the case of buildings or other land which are used for a purpose of any class specified in an order made by the Secretary of State, the use of the buildings or other land for any other purpose of the same class.   The classes relevant to this case are classes B1 (business), B2 (general industrial) and B8 (storage or distribution) as specified in the Town and Country Planning (Use Classes) Order 1987.
14.	By s.57, subject to the detailed provisions of that section, planning permission is required for the carrying out of any development of land.
15.	Part VII deals with enforcement.  Section 171A contains basic provisions:
“(1)  	For the purposes of this Act -
(a)	carrying out development without the required planning permission …
constitutes a breach of planning control.
(2)	For the purposes of this Act -
(a)	the issue of an enforcement notice (defined in section 172) …
constitutes taking enforcement action.”
16.	Time limits for enforcement action are contained in s.171B.  Subsection (1) lays down a 4 year limit for breaches consisting in the carrying out without planning permission of building, engineering, mining or other operations.  Subsection (2) lays down a like period for a breach consisting in change of use of a building to a single dwellinghouse.  The focus for present purposes, however, is on subsections (3) and (4)(b), which lay down a 10 year period for all other cases and allow an additional 4 year period for further enforcement action in certain cases (the “second bite” provision).  They read, so far as material: 
“(3)	In the case of any other breach of planning control, no enforcement action may be taken after the end of the period of ten years beginning with the date of the breach.
(4)	The preceding subsections do not prevent - 
…
(b)	taking further enforcement action in respect of any breach of planning control if, during the period of four years ending with that action being taken, the local planning authority have taken or purported to take enforcement action in respect of that breach.”
17.	General provisions governing the issue of an enforcement notice and the contents of a notice are contained in ss.172 and 173.  Section 173(11), upon which the appellant relies in support of the application for a certificate of lawful development, provides:
“(11)	Where -
(a)	an enforcement notice in respect of any breach of planning control could have required any buildings or works to be removed or any activity to cease, but does not do so; and
(b)	all the requirements of the notice have been complied with,
then, so far as the notice did not so require, planning permission shall be treated as having been granted by virtue of section 73A in respect of development consisting of the construction of the buildings or works or, as the case may be, the carrying out of the activities.”
18.	The right of appeal to the Secretary of State against an enforcement notice is governed by s.174.  By s.174(2), the grounds on which an appeal may be brought include:  
“(a)	that, in respect of any breach of planning control which may be constituted by the matters stated in the notice, planning permission ought to be granted …;
(b)	that those matters have not occurred;
…
(d)	that, at the date when the notice was issued, no enforcement action could be taken in respect of any breach of planning control which may be constituted by those matters.”
19.	On an appeal under s.174 the Secretary of State may, by s.176(1), correct any defect, error or misdescription in the enforcement notice, or vary the terms of the enforcement notice, “if he is satisfied that the correction or variation will not cause injustice to the appellant or the local planning authority”.
20.	Applications for a certificate of lawful development are governed by s.191.  The central provisions are subsections (4)-(6):
“(4)	If, on an application under this section, the local planning authority are provided with information satisfying them of the lawfulness at the time of the application of the use, operations or other matter described in the application, or that description as modified by the local planning authority or a description substituted by them, they shall issue a certificate to that effect; and in any other case they shall refuse the application.
(5)	A certificate under this section shall -
(a)	specify the land to which it relates;
(b)	describe the use, operations or other matter in question (in the case of any use falling within one of the classes specified in an order under section 55(2)(f), identifying it by reference to that class);
(c)	give the reasons for determining the use, operations or other matters to be lawful; and
(d)	specify the date of the application for the certificate.
(6)	The lawfulness of any use, operations or other matter for which a certificate is in force under this section shall be conclusively presumed.”
21.	Section 195 confers a right of appeal against a local planning authority’s refusal of a certificate or its failure to determine the application within the time laid down.
(1) The second bite issue
22.	The issue here is whether the inspector was correct to decide that Notice I was a valid second bite notice involving further enforcement action within the meaning of s.171B(4)(b) in respect of the same breaches of planning control as had been alleged in Notices B, D and E which the inspector quashed.  
23.	The effect of treating Notice I as a second bite notice was to push back the time limit for enforcement action to 10 years before the date of those earlier notices, i.e. to 7 March 1991, rather than limiting it to 10 years before the date of Notice I itself, i.e. to 4 February 1992.  This was potentially important, since the inspector found changes during the period March 1991 to February 1992 and took them into account when determining whether the mixed use on site as at the date of Notice I had come about through a material change of use.
24.	I have already set out the terms of s.171B(4)(b), which relate to the taking of enforcement action "in respect of any breach of planning control" if during the relevant period the authority has previously taken or purported to take enforcement action "in respect of that breach".
25.	The leading case on that provision is Jarmain v. Secretary of State for the Environment, Transport and the Regions [2000] 2 PLR 126.  The brief facts were that planning permission had been granted to the appellant for use of a mobile home on land, subject to a condition whereby the permission was limited in time.  Before the permission expired he had changed his accommodation from a mobile home to a permanent single-storey dwelling, the permanent dwelling having been constructed around a mobile home that had been damaged while being installed on the site.  Following expiry of the temporary permission, in March 1996 the local planning authority issued an enforcement notice alleging breach of condition in that the mobile home remained on the land.  In March 1998 that enforcement notice was withdrawn and a second notice was issued, in which the breach of planning control alleged was erection of a single storey building without permission.  The relevant issue was whether the second enforcement notice fell within s.171B(4)(b).  
26.	The inspector found that both enforcement notices were directed at the same structure and that, while the actual description of the breach differed, in issuing the second notice the authority had purported to take enforcement action in respect of the same breach as it had purported to do under the first notice.   The deputy judge upheld the inspector’s conclusion, saying at 133G-134F:  
“When section 171B is read as a whole it appears clear that the section is concerning itself with breaches of planning control and the time limits applicable when enforcing against these breaches.
Various types of planning control relating to different types of development are referred to in the section.  What the section is concerned with are the various acts of development that constitute the breaches of control, not the description of the substantive activities.  It is the subject matter of the enforcement notice, the actual development that is being referred to by the words ‘that breach’, rather than the words that have been used to characterise the development, that constitutes the breach of planning control.  The description of a breach cannot in itself be a breach of planning control.  What this proper interpretation means is that the sub-section cannot be used to cover two different physical developments or two different changes of use, but it can be used to cover the same actual breach of development control, which is described in different ways.  
This interpretation is clear enough from the wording of the section, but is also apt for illustration by the facts of this case.  The facts of the situation are that a permanent dwelling house had been constructed without planning permission by 12 April 1993.  That constituted a breach of planning control.  Such a breach is identified in section 171B(1).  The local planning authority purported (note that that is the word used in section 171B(4)(b)) to enforce against that physical development, a dwelling house construction, but, mistakenly, did not appreciate that the development carried out was a permanent dwelling house; they therefore described the breach as a mobile home still on site in breach of the time-limit condition.  That mistake did not change the nature of the breach of planning control, which was still construction of a permanent dwelling house without planning permission and it was plainly against that physical development that the local planning authority had purported to enforce.  When they learned of their mistake they correctly described the breach of planning control in a new enforcement notice, but it was still the same physical development construction that had always been the only breach of planning control under consideration, and, therefore, the second enforcement notice was enabled by the subsection and the inspector was correct in taking this approach.
This interpretation is also consistent with the purposes of the section which, as can be seen in the general note to the subsection in Vol 2 of the Planning Encyclopaedia (2-3598/1), removed the protection given to developers in previous legislation who succeeded in establishing technical errors in enforcement notices while time continued to run, so that cases arose when time for service of an enforcement notice without the defect had elapsed.”
27.	Before the Court of Appeal, the Secretary of State contended that the deputy judge’s reasoning was correct.  Counsel for the appellant submitted that the breach that founds the first enforcement notice must be the same as the breach that founds the second enforcement notice; and that in the instant case there were entirely different breaches alleged (in the first notice, a change of use of the land in breach of the condition in the temporary permission; in the second, the carrying out of a building operation without permission).  The Court of Appeal favoured the reading of the section adopted by the inspector and the deputy judge.  
28.	In giving his reasons, Roch LJ placed weight on avoiding a situation in which notices might be defeated on technical grounds.  He stated that the reading of the section for which counsel for the appellant contended "would lead to a return to the technicalities that bedevilled the enforcement of planning control prior to the passing of the 1990 and 1991 Acts" (136H).
29.	So too Brooke LJ contrasted the appellant’s purist approach with the pragmatic approach adopted by the inspector and deputy judge and, in preferring the latter, laid emphasis on the desirability of avoiding technicalities.  He stated (at 139C-140B and 141B-D):
“Anyone who had any experience of the operation of the former law relating to the enforcement of planning control knows that it was disfigured by time-consuming litigation over technicalities, raised by determined litigants who sought to evade the effects of enforcement action taken against them by local planning authorities on behalf of their local communities.
From time to time, there were judicial explosions on the topic. Among these, the most colourful was that of Templeman J in 1974, and the most resigned that of Mr Graham Eyre QC, sitting as a deputy high court judge in 1988.
In Eldon Garages Ltd v Kingston upon Hull County Borough Council [1974] 1 All ER 358, Templeman J ended his 18-page judgment at p375B with these  words:

The result of this submission, if I acceded to it, would be that the enforcement notice is a kind of spell by a witch doctor and unless the witch doctor gets the exact words of the incantation right, then the spell does not work.  Well, although, as the House of Lords pointed out, one has got to be very careful in these cases because of the individual rights involved, we have not yet got to that stage and I do not propose to begin getting near that stage… That being so, it seems to me that I must dismiss this summons.  This is not an enforcement notice which relates to Bleak House, and although counsel for the plaintiffs has argued this case very skilfully and has put forward every argument open to him, I intend no disrespect to him and no criticism of anybody when I say that it is time that the pettifogging was stopped and I dismiss this summons.

With a wearied resignation born of a professional lifetime of experience of all the difficulties posed by the existing law, Mr Graham Eyre QC said in West Oxfordshire District Council v Secretary of State for the Environment [1988] JPL 324 at pp324-5:

It… [is] perhaps remarkable that nearly four decades [have]… passed since the enforcement notice machinery first emerged in the Town and Country Planning Act 1947 during which time the legislature [has] made substantial amendments to the statutory provisions so as to remove or substantially reduce the powers of the courts to interfere on technical grounds, and yet this court [has]… been treated to a rehearsal of somewhat arid technicalities most of which [have]… a ring of nostalgia, in its true sense, and largely unwelcome familiarity.

I am quite satisfied that one of parliament’s main purposes in 1991, in overhauling Part II of the 1990 Act, was to spare those like Mr Eyre the pain of returning to those arid technicalities.”

…

“It appears to me that if we were to allow this appeal, we would be in danger of allowing enforcement law to return, in part, to the world of pettifoggery and arid technicalities that attracted such strong judicial disapprobation in the 1970s and 1980s.  In my judgment, this court ought to be very slow to depart from the approach to the interpretation of section 171B(4)(b) that was adopted by a deputy judge with great experience in the planning field.  He was satisfied that the relevant breach of planning control consisted of the erection of the unauthorised structure in the position marked on the plan attached to the enforcement notice.  The council purported to take enforcement action in respect of that breach by their first notice, but failed to do so because they misdescribed the breach.  They were therefore entitled by section 171B(4)(b) to take further enforcement action because four years had not elapsed since the date of the earlier purported action.”
30.	The concerns underlying the Court of Appeal’s conclusion are, however, perhaps best illustrated by Sedley LJ’s judgment (at 141E-142A): 
“For the reasons given by Roch and Brooke LJJ, I agree that this appeal fails.  To allow it would be to set a premium once more on technical challenges to enforcement notices that have misled nobody.  It would also, in a case like the present one, be to reward conduct that, at best, was devious and, at worst, deceitful.  As is apparent from the account given by Roch LJ, the appellant continued to claim that he had a mobile home on the site for as long as it suited him to do so.  Then, when he thought the time was up for enforcement, he asserted that it was a permanent structure.  When one looks – in the unaccountable absence of photographs – at his account of what he had done to the mobile home, it becomes easier to see why the council’s officials were taken in.  He had, by his own account, set the structure on timbers, thereby presumably elevating it from the ground; he had put on a board and felt roof; and he had retrieved other, unspecified, materials ‘for use in the construction’.
It would make a farce of the legislation if, by claiming that one unlawful use was a different unlawful use, a landowner could take advantage of the four-year limit and acquire immunity from process for something he had known all along was unlawful.  Miss Lieven’s submission has satisfied me that to read the legislation as eschewing form in favour of substance does not give a slack local authority, at least in certain instances, an unintended length of time in which to get their notice right.  The second notice must not only relate to the same facts as constitute the breach to which the first notice related, but must be served within the period for which the first one is to be taken to have been good, namely four years.”
31.	In order to assess the rival submissions as to the application of the approach in Jarmain to the circumstances of the present case, it is necessary first to compare the contents of the earlier notices (Notices B, D and E) with the contents of the later notice (Notice I) and then to examine the inspector's reasons for quashing the earlier notices and for treating the later notice as a valid second bite notice.
32.	Notice B was expressed to relate to land comprising effectively the whole of the site, but the alleged breach was: "Without planning permission, change of use of the land involving the use of the building hatched black on the attached plan for industrial purposes and commercial storage purposes". The "building hatched black" was units 9 and 10.
33.	Notice D was also expressed to relate to land comprising effectively the whole of the site.  The alleged breach was:  "Without planning permission, change of use of the land involving the use of Unit 8 (shown hatched black on the plan) for the storage, crushing and recycling of aluminium".
34.	Notice E was likewise expressed to relate to land comprising effectively the whole of the site.  In this case the alleged breach was:  "Without planning permission, change of use of the land to use for the open storage of materials not ancillary to the agricultural use of the land".
35.	Notice I was expressed to relate to land comprising only part of the site, namely planning unit C (i.e. an area including units 3 to 10 and the southern and northern yards).  The alleged breach was: "Without planning permission, change of use of the land to a mixed use for Class B1, B2 and B8 uses, agriculture, hay and straw dealing, haulage depot and building and demolition contractor's depot".
36.	The inspector, however, corrected Notice I so that the alleged breach was change of use to a mixed use "consisting of agriculture, agricultural contracting, hay and straw dealing, storage (including the storage of helicopters), a vehicle haulage operator's depot, a building and demolition contractor's depot, motor vehicle servicing and repairs (including jet skis), courier businesses involving storage and distribution and a carpentry business" (decision letter, paragraph 168).  He considered the issues before him on the basis of the notice so corrected.
37.	The inspector's reasons for finding that Notices B, D and E were defective and could not be corrected without injustice are set out in paragraphs 27-29 of his decision: 
“27.The problem, in my opinion, is in the allegations as set out in the Notices; each alleges a ‘change of use of the land involving the change of use of…’ either a particular building or all the open area outside of the buildings.  I consider the Notices are not invalid on their face but the allegations are too vague to be upheld as issued.  They do not specify what material change of use has taken place nor include all the uses that are taking place within the planning unit; be it the one as delineated on the plan attached to the Notices B, D and E or the smaller area delineated on Notice I (which both parties agreed, at the resumption of the inquiry in May, was the correct planning unit at which all the Notices should be aimed).
28. As to the correction of the Notices, clearly I have wide powers of correction and can do so as long as there would be no injustice.  Submissions were made regarding this and the possibility of amalgamating the Notices at the inquiry, in writing during the adjournment and also in closing submissions.  The appellant argued that if I corrected the Notices there would be people/businesses who had not appealed against them because they did not think the Notices concerned them and they could not appeal now.  Additionally, there were buildings (eg units 6 and 7) and some users of the open yard not covered by the Notices as issued but they would be affected if the Notices were corrected to include all the relevant uses in the description and, consequently, the requirements.
29. The Council in closing submissions accepted this point but submitted that the issue of Notice I had resolved the matter as everyone had now been served with a copy of the Notice and had the opportunity to lodge an appeal.  Further, it was submitted that as the intention of Notice I was the same as B, D and E there would be no injustice if they were corrected, nor if they were amalgamated into one Notice.  Whilst I agree that the site owner/appellant could not really be in any doubt as to what the Notices were aimed at, it does not get over the fundamental point that the Notices are vague.  In correcting them either individually or by amalgamation, I consider that their scope would be widened; other buildings, uses and users would be affected by them and I conclude, therefore, that in those circumstances there would be injustice.  I will, therefore, quash Notices B, D and E”
38.	His summary of the arguments relating to the status of Notice I and his reasons for holding that it was a valid second bite notice are set out in paragraphs 30-32: 
“30.The appellant argued that Notice I could not be considered as a second bite notice as it was for a fundamentally different allegation.  I acknowledge that the area included in Notice I is different and also that the allegation itself following the general agreement reached at the inquiry about how it ought to be corrected (and set out in Section A.c above) is different.  There is also the possibility that it needs further correction after considering the evidence in detail on the relevant ground (c) and (d) appeals.
31. On the first two days of the inquiry there were numerous legal submissions including those regarding the validity of the Notices B, D and E in particular.  I am clear from all the evidence put forward that the Council were trying to achieve the cessation of all those uses at the site which did not have planning permission or could not be proved to be lawful and I have no doubt that the appellant (who was also the site owner) was aware that the notices were issued with that intent.  I have concluded that the Council had not made the right allegations and I could not correct them without causing some injustice.  However, both during the opening two days of the inquiry, when the Council, during an adjournment, tried to produce an amalgamated Notice and since then the Council have tried to get the allegation right.  That resulted in the issue of Notice I and whilst as originally worded it was still unacceptable, I consider it can be corrected (as set out in Section A.c).
32. In these circumstances I consider that it does purport to relate to the same breach of planning control even though the uses in Units 6 and 7 were not included in the earlier Notices; some of the occupiers were also not included in the earlier Notices but I am satisfied that the uses were, bearing in mind the wide reaching wording of the allegations.  I will therefore, deal with Notice I on the basis that it is a ‘second bite notice’ and, in my opinion, it supersedes Notices B, D and E (which, I have already concluded should be quashed) wording correctly the allegations that those three Notices were aimed at.”
39.	For the appellant, Mr Clay submits that there is an inconsistency between the inspector's finding that the earlier notices could not be corrected individually or by amalgamation without injustice, because it would widen their scope, and his finding that the later notice related to the same breach of planning control as the earlier notices.  In any case it was not properly open to him to find that the later notice did relate to the same breach of planning control, or to the same facts, as the earlier notices.  The inspector also relied erroneously on the council's intentions, i.e. what the council was trying to achieve by the earlier notices, rather than on the breaches actually alleged in them.  Thus, in applying s.171B(4)(b), he either misdirected himself or reached a conclusion not reasonably open to him.  His correction of Notice I did nothing to remedy the problem.
40.	For the First Secretary of State, Mr Mould submits that it is plain from the decision letter that the inspector's approach was consciously that laid down by the Court of Appeal in Jarmain.  Thus there was no misdirection.  The conclusion he reached was reasonably open to him on the facts, as can be seen from the relevant paragraphs of the decision read against the background of his preliminary findings (in particular at sections 4 and 5 of appendix 2).  The breach alleged in Notice I was change of use of planning unit C to a mixed use of the whole site.   As to the concept of a mixed use, see Burdle v. Secretary of State for the Environment [1972] 3 All ER 240 at 244d, where Bridge J described the case of a composite (i.e. mixed) use of a planning unit "where the component activities fluctuate in their intensity from time to time, but the different activities are not confined within separate and physically distinct areas of land".  The inspector's approach in correcting the notice so as to specify all the components of that mixed use was correct and in accordance with the guidance given in paragraph 2.10 of Circular No. 10/97, "Enforcing Planning Control".  He considered the earlier notices to be flawed because they took a piecemeal approach, targeting individual components of the mixed use rather than the mixed use itself; and he found that they could not be corrected without injustice because they were vague, they did not include all the components and other occupiers had not been served.  But the fact was that by those earlier notices the council had been targeting the same breach of planning control, namely the mixed use, although it was described in different ways.  The notices had been seeking to achieve the cessation of the mixed use of the land.  
41.	Mr Mould further submits that the failure in the earlier notices to embrace the mixed use as a composite whole was a technical flaw of a kind that the second bite provisions are apt to deal with. As a matter of principle, there can be a valid second bite notice even where earlier notices are incapable of being corrected without injustice.  If the second bite provisions applied only where earlier notices could be corrected without injustice, the provisions would not be needed.  The appellant's case, he suggests, comes down to asking the court to rule that the Jarmain approach is limited to cases of misdescription of precisely the same underlying facts and does not embrace a second bite notice which incorporates within the alleged breach more extensive activities and a wider area than covered by earlier notices.  But Jarmain should not be given such a narrow application.  The policy considerations that caused the court to adopt the approach it did in Jarmain apply with equal force here.  It is particularly likely in a complex mixed use case that the local planning authority will fail to cover the full extent of a mixed use or of the area within which it is carried out; and it would be surprising and unsatisfactory if the authority were prevented from relying on the second bite provisions to get it right.
42.	The issue addressed by those rival submissions is the one issue of potential importance in the case; and fortunately it is less bedevilled by factual detail than the rest of the case.  For the reasons given below, and with a considerable degree of reluctance, I have concluded that the appellant's submissions on it are well founded.
43.	In broad terms it is no doubt true, as the inspector found, that the council was trying by the earlier notices to achieve the cessation of all those uses at the site which did not have planning permission or could not be proved to be otherwise lawful, and that the appellant was aware that the notices were issued with that intent  But in considering the application of s.171B(4)(b) I think it necessary to focus not on the council's broad intention but on the terms of the enforcement notices themselves and in particular on the actual breach or breaches of planning control alleged in them.
44.	The earlier notices were directed in terms at a number of specific activities or uses alleged to give rise to a material change of use.  In the case of Notice B the alleged breach was a change of use involving use of units 9 and 10 for industrial and commercial storage purposes.  In Notice D it was a change of use involving use of unit 8 for the storage, crushing and recycling of aluminium.  In Notice E it was a change of use of the entire site to use for the open storage of materials not ancillary to agricultural use.  
45.	It may be that, as the council suggested in its submissions to the inspector (see appendix 2, paragraph 4.2), the notices were all targeting component parts of a mixed use, though that is not how it is put in the notices themselves.  The problem, however, is that even if viewed collectively the notices cannot be said to have targeted the whole of the mixed use at which Notice I was directed.  The breach alleged in Notice I is a change of use of planning unit C to a mixed use with multiple components as described in the original notice and as corrected by the inspector.  That encompasses a wider range of components than the aggregate of uses covered by the earlier notices.   
46.	The disparity between the earlier notices and Notice I is inherent in the inspector's own finding that to correct the earlier notices so as to cover all the uses said to be taking place on the planning unit would be to widen the scope of the notices and to affect other buildings, uses and users.  It may be that most of the components of the mixed use alleged in Notice I were covered by the earlier notices, and possibly that the most important components were so covered:  the inspector mentions in particular the uses in units 6 and 7 as not being included in the earlier notices.  But there still exists a material disparity.
47.	It follows in my judgment that Notice I goes wider in substance than the earlier notices and is directed at additional facts.  It does not simply describe more accurately what was misdescribed in the earlier notices; it goes further than the earlier notices.  That takes the case outside the scope of the reasoning in Jarmain.  Whilst I am prepared to accept that the Jarmain reasoning is capable of applying in principle where a single second bite notice covers breaches alleged in a number of earlier notices, it does not in my view apply where the breach alleged in the new notice goes wider in substance than the totality of breaches alleged in the earlier notices.
48.	I acknowledge the force of the policy considerations referred to in Jarmain, upon which Mr Mould put particular weight in his submissions.  It seems to me, however, that to hold that s.171B(4)(b) as interpreted in Jarmain does not apply to Notice I is not to allow technicality and form to prevail over substance.  The problem goes beyond one of technical defects in the earlier notices.  Even if the council intended by those earlier notices to target the entirety of the mixed use on the site, the notices themselves fell materially short of doing so whether viewed individually or collectively. That falls outside the range of circumstances at which s.171B(4)(b) is aimed. 
49.	Accordingly I conclude that the inspector erred in holding Notice I to be a valid second bite notice.  It does not matter for present purposes whether the error is described as a misdirection of law or the making of a finding not reasonably open on the facts. 
50.	I have indicated that it is a conclusion I reach with a considerable degree of reluctance.  That is because, subject to any further submissions from counsel about the exercise of the court's discretion, the consequence of this error would seem to be that the decision must be quashed.  That is particularly unfortunate in a case where it seems likely that the inspector's basic conclusion would have been the same if he had confined his attention to the 10 years preceding the date of Notice I, and where the decision was otherwise a thorough and impressive piece of work in relation to which, as explained below, I reject all the other grounds of challenge.  
51.	In case I am wrong in my conclusion on the second bite issue, and since the rest of the case was the subject of full argument before me, I propose still to deal with the other issues.
(2)  The material change of use issue
52.	In considering the appeal against Notice I under ground (d) of s.174, the inspector found that the existing mixed use on the site had come about through a material change of use from the use which had been there on 7 March 1991.  The issue is whether he erred in his approach to material change of use. 
53.	The relevant section of the decision letter is lengthy (paragraphs 58-109).  The inspector proceeded by summarising the parties' basic contentions (paragraphs 61-62), considering the evidence of actual use and activity on the site up to the start of 1991 (paragraphs 63-71) and since the start of 1991 (paragraphs 72-85), assessing in the light of his findings the changes since the start of 1991 (paragraphs 86-93), and finally expressing his reasoned conclusions on the materiality of the changes during the relevant period (paragraphs 94-109). 
54.	As regards the situation at the start of 1991, the inspector concluded, as a matter of fact and degree, that there were two distinct planning units within the one unit of occupation, with the southern yard in agricultural use and the northern yard in mixed use (paragraph 70).
55.	He identified a number of changes since the beginning of 1991.  Amongst other matters referred to was that the southern yard also came into mixed use and the two planning units became merged into a single planning unit with a mixed use (paragraph 75).  In mid-1991 the appellant erected unit 9 as an extension to unit 10 and also extended the area covered by the planning unit, taking in some land at the northern end of the site (paragraph 76).  In 1995 an area of land immediately to the north of unit 9, which had previously been in agricultural use, was taken into the planning unit and was used thereafter for commercial purposes (paragraph 77).  There were physical alterations to buildings, including in particular to units 9 and 10 (paragraphs 78-82).  There were also various changes to the actual uses taking place on the site and to the occupiers (paragraphs 83-85).  
56.	In his assessment of the changes since the start of 1991, the inspector stated first that in his view the correct approach should be to take the planning unit as it existed in March 1991 and then look at all the physical changes since then as well as the changes in uses and occupiers.  The following are extracts from paragraphs 87-93 dealing with those changes:
“From March 1991 the area used for the various uses increased by just over 50% by March 2001, in my view a considerable increase.  In terms of the appearance of the land it also resulted in open storage taking place on land to the north of the building …  [T]he size of the main covered area was basically doubled when unit 9 was added to unit 10 later in the same year and … it was generally used for non agricultural purposes from day one ….   Then in 1998 the whole structure was virtually rebuilt … and it again changed totally in character in my view, particularly in how it could be used.  What had been basically a 'Dutch barn' with open ends and some corrugated sheeting on the two side elevations of a plain steel framework was turned into a purpose built industrial type building (despite the corrugated cladding on the outside which can also be found on a modern agricultural building) with block work walls and partitions, including some first floor sections, and much of it with a proper concrete floor.  … The changes in the type of space offered for rent after the 1998 alterations, in my view, facilitated a change in the type of use there.  It changed from a basically 'open' covered area under the roof of units 9 and 10 … to one that provided secure, weatherproof storage on a large scale that would not have been possible in the old units 9 and 10.  … Further, it has resulted in the occupation by 2 companies specialising in the delivery of parcels which have more vehicles and staff on site than most and the establishment of a company … which also has many staff and vehicles on site ….  It was not disputed that these three occupiers had a higher generation of traffic to and from the site than others nor was the answer … that there had been more than a doubling of traffic movements at the site in the three years 1999 to 2002 …. This has also resulted, in my view, in a materially different character of use at the site…. I acknowledge that the number of occupiers has remained fairly constant over the relevant period ….  I also consider that … the various uses undertaken by those occupiers have not, in principle, been different in terms of the number of uses that have been taking place at any one time and the general description of what they did ….  Some uses that were there at the start of 1991 ceased; others commenced during the 1990s and some were there for just short periods ….  The sorts of vehicles, materials and equipment stored/parked at the site by them was not that different to other existing occupants … so there was not, in my view, a material difference there.   However, I consider that the situation changed after 1998 when the major building alterations were carried out ….”
57.	There followed the inspector's conclusions.  I think it necessary to quote paragraphs 94-100 in full:
“94.In my view, there were fundamental changes at the appeal site between March 1991 and March 2001.  These were the increase in the land area covered by the use; the increase in building mass and, therefore, the consequent increase in the amount of usable covered floor space; the large increase in the area of outside storage; the virtual rebuilding of units 9 and 10 almost as purpose built commercial buildings; the nature of the more recent occupiers of the site, in particular, of the buildings, and also the level of traffic associated with the various uses and occupiers of the site particularly the more recent tenants.
95. The changes summarised above have resulted in a mixed use that is undertaken on a much larger area.  The mixed use in March 2001 was not actually on the same site at all as that in March 1991 but on a land area that had grown by over 50%, the increase in area taking place through increases on two different occasions.  The new area taken into the planning unit had been in agricultural use and, in my opinion, the planning unit as it was in March 2001 had only existed since late 1994 or early 1995 at the earliest.  Even if my conclusion is wrong on that as a point of law, ie., the simple increase in the size of the unit is not sufficient to preclude a success on ground (d), there are still the other changes to take into account.
96. The first increase in the size of the planning unit in 1991 was also large at about 0.1 hectares but that increase in area facilitated the building of the large extension that became known as unit 9; about 40% of its floor space was in the extended site.  Taken together with the unit 9 extension, my opinion is that the site, even as first enlarged, late in 1991, resulted in a material change in the appearance of the land through the increased level of outside storage, the increased use taking place in an enlarged building and the alterations to the building itself which had approximately doubled in size with an extension of nearly 1100 square metres floor space.
97. There were then the further changes to the buildings in 1998.  Units 9 and 10 were virtually rebuilt around their framework skeleton and some of the existing sheeting/panelling that formed the walls and roof.  They became what I would describe as a complete building with four solid walls and a roof, numerous solid internal partition walls and even some first floor accommodation.  Use of the site, in my view, became far more intensive because of these changes as I believe the photographs taken over a long period showed, particularly regarding the level of storage both outside and inside the buildings.
98. The 1998 changes to the buildings and the different occupiers that came, in my view, as a result of the more permanent and secure space available, also led (and still does) to a far higher level of traffic to and from the site than experienced before, both in terms of staff and business vehicles.  This mainly came through the introduction, not long before the issue of the Notice I, of some different types of uses (in particular the corporate games organiser and the two courier companies) with materially greater traffic generation than the uses that had been there before.
99. Whilst I accept that it might not be possible to say that any one of these changes by itself resulted in the material change in the use of the site, I consider, as a matter of fact and degree, that the use at 7 March 2001 was materially different to that which had existed on 7 March 1991.  It was not just a more intensive use of the site but one where the activities making up the uses, the land area used; the extent of storage, both inside and outside; the buildings in which the uses were being undertaken and the level of traffic generated, if all taken together, describe a use that is materially different in character and nature.
100.I conclude, on the basis of the evidence that was put before me, that those changes were so significant that the mixed use there at the time the Notice was issued had, by its very different nature and character, come about through a material change of use from the use which had been there on 7 March 1991.”
58.	He went on, in paragraphs 101-103, to deal with points relevant to the precise terms of the correction to Notice I.  In paragraphs 104-105 he considered whether there were any particular uses that could be regarded as lawful and should be excluded from the scope of the requirement to cease activities on the site.  He found that, apart from agriculture, the only uses which should not be required to cease were hay and straw dealing and agricultural contracting.  In paragraph 106 he set out his conclusion that the appeal against Notice I on ground (d) of s.174 failed.  
59.	It is convenient to mention at the same time how the inspector dealt with the s.195 appeal in relation to the application for a certificate of lawful development.  He pointed out in paragraph 107 that the appeal concerned a slightly different time period, going back 10 years from 22 January 2001 (the date of the application).  He acknowledged in the same paragraph that he had the power by virtue of s.191(4) to issue a certificate in terms different from those applied for where a smaller area of land for the use applied for could be identified or where some similar but different use was found to be lawful on all or part of the site.  In paragraph 108 he found no material difference arising from the fact that the relevant date of 22 January 1991 was earlier than applicable to Notice I.  In the light of his conclusions on the ground (d) appeal against Notice I he found in paragraph 109 that the only lawful uses were agricultural contracting and hay and straw dealing and that a certificate should be granted for those two uses.
60.	For the appellant, Mr Clay submits that the inspector adopted the wrong approach to the question of material change of use and erred in finding a change of use by virtue of a change in the extent of the planning unit, the construction of new buildings and intensification of use. 
61.	As to change in the extent of the planning unit, Mr Clay submits that the inspector erred in finding in the first place that there had been two distinct planning units at the start of the period.  There was no physical separation between the northern and southern yards and there was no difference in circumstances that could justify a finding that the two yards constituted separate planning units in 1991 yet formed a single planning unit, planning unit C, in 2001.  
62.	But even if that finding was open to him, it is submitted that the inspector's focus should have been on the activities in the northern yard and he erred in taking into account the extension of the planning unit by the inclusion of the southern yard and of land to the north of unit 9.  An extension of the planning unit is not in itself a breach of planning control.  Whilst he was entitled to find that the areas into which the commercial uses had extended could not benefit from lawful use rights, that did not help him to answer the question whether there had been a material change of use of the area where commercial activities had been carried on since the beginning of the relevant period.  If there was no material change of use of the northern yard, then the appellant was immune from enforcement action in relation to that area.  The inspector seems to have appreciated this in his comments on the application for a certificate of lawful development (paragraph 107), but failed to approach the matter in this way in his analysis of material change of use.  
63.	As to the construction of new buildings, Mr Clay submits first that the inspector's finding that a new building had been constructed was based on a mistaken inference.  In paragraph 79 the inspector stated that the appellant withdrew his ground (b) appeal against Notices A and G and "has, therefore, accepted the allegations in the Notices; that in Notice A alleging that the alterations he undertook [to units 9 and 10] had resulted in a new building on the site".  The appellant did not in fact withdraw the appeal under ground (b).  He simply did not pursue it in closing submissions because in the circumstances it did not help.  No adverse inference can be drawn from that.  If one strips away the erroneous inference and looks at the underlying facts, what happened to units 9 and 10 - the addition of cladding and internal subdivision - could not amount to the construction of a new building.
64.	In any event it is submitted that the inspector was wrong to regard the construction of a new building as giving rise to a material change of use in circumstances where it did not by itself create a new planning unit or a new chapter in the planning history.  Reliance is placed on the decision of the Court of Appeal in Jennings Motors Ltd v. Secretary of State for the Environment [1982] JPL 181, in particular the observations of Lord Denning MR at 183 that "[a]ll that had been done was to erect a new building in place of an old one, on a little portion of the site" and that the occupiers were entitled to use of their existing use rights inside the new building.
65.	As to intensification of use, Mr Clay submits that it was not open to the inspector to rely on a material change of use through intensification of use of the site in a case where that was not the change of use alleged in the enforcement notice.  In this connection he cites Royal Borough of Kensington and Chelsea v. Secretary of State for the Environment and Mia Carla Ltd [1981] JPL 50, in which the court held that an inspector had properly rejected an alternative case of material change of use by intensification, since that was not the material change of use alleged in the enforcement notice and was therefore not before him on the appeal.  Exactly the same reasoning should apply to Notice I.   A subsidiary point raised in Mr Clay's skeleton argument is that a finding of intensification was not canvassed at the inquiry and it was therefore unfair to rely on it.
66.	If, instead of taking into account those irrelevant considerations, the inspector had focused on the question whether there had been any material change of use in relation to the northern yard, Mr Clay submits that the only reasonable answer would have been that there was no such change.  The description of activities in Notice I, whether in its original or corrected form, is equally apt to describe the situation in the northern yard as the inspector found it to have existed in 1991.  There was no material difference in the character of use of the land.  Any differences in the number and descriptions of uses on site were immaterial since they all fell within classes B1, B2 or B8 of the Use Classes Order and by virtue of s.55(2)(f) of the 1990 Act uses within the same class cannot give rise to a material change of use.   In his skeleton argument Mr Clay also referred in this connection to Article 3(4) of the Use Classes Order, which provides that "where land on a single site … is used for purposes consisting of or including purposes falling within classes B1 and B2 …, those classes may be treated as a single class in considering the use of that land" for the purposes of the Order.
67.	Mr Clay produced the following written summary of his submissions as to the approach that the inspector ought to have adopted in a case where, as he put it, the area over which unauthorised activities have taken place has not remained consistent:  "(1) Does the site on which the activities are taking place contain or include any part of or all of the area on which unauthorised activities were taking place ten years prior to the issue of the [enforcement notice] and have taken place continuously in the intervening period?  If yes consider question 2.  If no then not immune.  (2) Is the use described in the allegation materially different from the description of the use which was taking place on (that part of) the site 10 years prior to the issue of the notice (and continuously in the intervening period).  If no then use on site (or relevant part thereof) is immune.  If yes consider question 3.  (3) If materially different, does the mix of uses fall within the same Use Classes at both beginning and end of the period.  If no, then material change of use so no immunity; if yes then no [material change of use], so uses immune."
68.	For the First Secretary of State, Mr Mould starts by observing that, having regard to the terms of s.174(2)(d) (appeal on the ground "that, at the date when the notice was issued, no enforcement action could be taken in respect of any breach of planning control which may be constituted by those matters"), the basic issue for the inspector to resolve was whether the mixed use alleged in Notice I was no longer capable of enforcement by virtue of the ten year time limit.  
69.	Mr Mould submits that the inspector approached the matter in a clear and sensible way, looking at the planning unit as it existed at the date of the enforcement notice and considering whether the mixed use at that date was materially different from the use in 1991.  His conclusion that there had been a material change was based on the combined effect of the various changes.  He acknowledged that there were generic similarities in the activities carried on over the period, but considered that the various changes e.g. in the way in which they were conducted, the extent to which they were conducted and the buildings where they were conducted (affecting scale and intensity of use) were such as to give rise to a material change of use.  All the matters he took into account were properly related to the character of the use of the land.  He made an unremarkable and legitimate planning judgment as a matter of fact and degree.
70.	As to the planning unit, there is no issue over the inspector's conclusions concerning the existing planning units at the site (and his analysis accorded anyway with what was said by Bridge J in Burdle) and it is common ground in particular that Notice I was properly directed to the area of land identified as planning unit C.  The inspector's use of that planning unit as a tool for assessing the materiality of any changes during the ten year period is orthodox and correct:  the question is whether the mixed use of that planning unit at the date of the notice involves a material change from uses previously carried on during the ten year period.  The fact that there were different planning units at the beginning of the period does not necessarily mean that there has been a material change of use, though it tends to suggest it.  In any event the changes leading to the creation and extent of the present planning unit are matters properly taken into account.
71.	As to the construction of new buildings, Mr Mould submits that Jennings Motors Ltd does not assist the appellant.  The majority reasoning, in the judgment of Oliver LJ with which Watkins LJ agreed, was simply that the erection of a new building does not necessarily constitute a new planning unit and give rise to the loss of existing use rights; it is a question of fact and degree in every case (see pages183-184).   In the present case the inspector looked not just at the changes to the buildings themselves, but at the effect this had on the activities carried on in them and in connection with them.  Thus, for example, the physical changes have brought about major increases in storage activity and a greater intensity of activity on site.  They in turn have materially affected the appearance of the site and have resulted in significant increases in traffic movements.  These were all relevant considerations which properly informed the overall conclusion that there had been a material change of use.
72.	It is submitted that, having regard to his summary at paragraph 7 of the decision (where he records the appellant's acceptance that the appeals under ground (b) were not being pursued), the inspector was entitled to proceed on the basis that the appeal against Notice A under ground (b) of s.174 had been withdrawn and that the appellant was therefore to be taken to have accepted that the alterations to units 9 and 10 resulted in a new building.  But in any event this is said to be an arid point to debate, since the inspector went on to carry out his own analysis of the nature and effect of the works in question on the basis of the other evidence before him; an analysis which led him to exactly the same conclusion (see paragraphs 80-82 and 88-89; see also paragraphs 126-128).
73.	As to intensification, Mr Mould submits that it is clear that the inspector did not proceed on the basis that there was a material change of use by intensification, so as to fall into the error referred to in Mia Carla of relying on a material change of use different from that identified in the enforcement notice.  Intensification in the form of additional activities, facilities, traffic, etc.,  is properly taken into account as part of the normal assessment of whether there has been a change in the character of the use of the land so as to give rise to a material change of use:  see e.g. Lilo Blum v. Secretary of State for the Environment [1987] JPL 278 at 280-281.  That is how the inspector proceeded in this case.   That is clear both from the detailed analysis and from the conclusions in paragraphs 99-100, where it is stated in terms that "[i]t was not just a more intensive use of the site but one where the activities making up the uses, the land area used; the extent of storage, both inside and outside; the buildings in which the uses were being undertaken and the level of traffic generated, if all taken together, describe a use that is materially different in character and nature".
74.	Mr Mould further submits that the appellant's reliance on s.55(2)(f) and the Use Classes Order is misplaced.  The Use Classes Order does not apply to mixed use of the land even if some of the activities comprised within that mixed use would, if taken by themselves, fall within use classes.  In any event some of the activities comprised within the mixed use are sui generis and would not fall within a use class even if taken by themselves.  Further, Article 3(4) is plainly incapable of assisting the appellant since it refers to classes B1 and B2 but not class B8, yet the activities comprised within the mixed use include storage uses falling within class B8 rather than within B1 or B2.
75.	I propose to express my conclusions on this issue relatively briefly, since I accept the substance of Mr Mould's submissions.  In my judgment the inspector approached the matter correctly and reached a carefully reasoned and rational finding that there had been a material change of use.
76.	The inspector was right to consider the planning unit and the use as they existed at the date of the enforcement notice, and to consider whether that use was materially the same as at the beginning of the relevant period or whether there had been a material change of use.  No issue is taken over the identification of planning unit C as the relevant planning unit as at the date of Notice I.  In my view it was reasonably open to the inspector to find on the facts that the northern and southern yards had constituted separate planning units in 1991 and had subsequently merged into a single planning unit which had also been subsequently extended.  These were pre-eminently matters of judgment for him.  He did not treat the change in the planning unit as necessarily giving rise to a material change of use, but looked at the change in the planning unit, and the related question of how the site was being used, as part of his overall consideration of whether there had been a material change of use.  This was a lawful approach.
77.	So too the inspector did not proceed on the basis that the construction of a new building arising out of the works to units 9 and 10 in 1998 necessarily gave rise to a material change of use.  Once more he considered the relevant works, and their practical consequences for the use made of the site, as part of his overall consideration of material change of use.  Such an approach was consistent with what was said in Jennings Motors Ltd and was again in my view lawful.
78.	I agree with Mr Mould that it makes no practical difference whether the inspector was correct in finding that the ground (b) appeal against Notice A had been withdrawn and that the appellant had thereby impliedly accepted that the works resulted in a new building.  The inspector clearly reached the same finding about the construction of a new building on the basis of his own detailed examination of the evidence concerning the works, and it was a finding reasonably open to him on that evidence.
79.	The inspector looked at intensification of use as part of a normal assessment of whether there had been a change in the land use character.  It was legitimate for him to do so in determining whether there had been a material change of use to the existing mixed use as alleged in the notice.  He did not find a material change of use by intensification or depart in any way from the change of use alleged in the notice.  Nothing in Mia Carla casts doubt on the correctness of his approach.  There was no unfairness in his taking intensification into account in the way he did.
80.	I do not consider the appellant's case to be assisted by reference to the Use Classes Order.  Each of the points made by Mr Mould is in my view well founded.  I would place particular emphasis on the threshold point that the Use Classes Order has no application to a mixed use:  the mixed use does not itself fall within any class and a finding of material change of use is not avoided simply by showing that a component falling within a particular class has been substituted for another component falling with the same class.  I dealt with a similar point recently in Belmont Riding Centre v. First Secretary of State [2003] EWHC 1895 (Admin) at paragraph 31 of the judgment.
81.	The inspector accepted that there were similarities in uses carried on over the relevant period.  But he was reasonably entitled to find, as a matter of fact and degree, that the combined effect of the various changes he identified was that the mixed use at the time of the notice was materially different in character and nature from that at the start of the period and that it had come about through a material change of use.  
82.	I therefore find against the appellant on the material change of use issue.
(3) The previously established lawful use issue
83.	I have already mentioned how the inspector dealt with the related s.195 appeal concerning the application for a certificate of lawful development, including his finding at paragraphs 104-105 that only a very limited number of uses could be regarded as lawful and should be excluded from the scope of the requirement in Notice I to cease activities on the site.  The issue here is whether he erred in his consideration of whether other, commercial uses had been carried on by the appellant long enough to become lawful.  
84.	The relevant passage of the decision reads in full:
“104.The Council’s planning witness accepted that the use of the site for hay and straw dealing and agricultural contracting was lawful; it had gained that lawfulness in July 1992 having commenced 10 years before that date.  The appellant also only referred to these two uses as being lawful, both in questions to his own planning witness and the Council’s planning witness.  These were the only alleged uses that the Council considered should not be required to cease other than agriculture which it was agreed was not ‘development’
105. No similar point was put regarding the other uses that the appellant claimed to have carried out himself at the site and no detailed evidence was put forward regarding these other uses; that contained in the supplementary proof of the appellant’s planning witness was really only diagrammatic in relation to where it took place and general in terms of the type of use taking place in a building or amongst the open storage.  The appellant was also just one of a number of people/companies that carried out such uses which were all part of the mixed use which I have already concluded materially changed in the relevant 10 year period.”
85.	Mr Clay submits that the inspector erred in law in considering only the last 10 years and acted irrationally in dismissing the appellant's case as to other lawful uses.  As to the former point, it is not enough to compare the existing use with the use 10 years ago, since immunity from enforcement may have arisen by reason of some previous period of continuous use.  As the inspector said in paragraph 104 in relation to hay and straw dealing and agricultural contracting, "it had gained that lawfulness in July 1992 having commenced 10 years before that date".  Yet in relation to other activities he did not ask himself whether there was a continuous period of 10 years within which they had been carried on; and the last sentence of paragraph 105 shows that he only considered the last 10 years.  
86.	The point on irrationality relates to the first sentence of paragraph 105, which is said to be a travesty of the evidence put forward.  In addition to a detailed schedule from the appellant's planning expert, there were 45 or so statements from people who occupied the land at various times, giving primary evidence of the activities carried on there.  The inspector does not refer here to any of them.  In the light of that body of evidence it was perverse to deal with the matter in this way.
87.	Mr Mould submits that the inspector made clear what he was deciding and why.  It was common ground, and found by him, that hay and straw dealing and agricultural contracting had become lawful.  But no similar point was put forward as regards other uses.  There was certainly evidence that activities were being carried on as part of a mixed use of the site, and the inspector's earlier detailed analysis of the situation up to 1991 shows that he had this evidence clearly in mind.  It was not, however, contended that any specific individual component of that mixed use had become lawful in its own right.  The appellant's closing submissions at the inquiry did not raise the point, but focused on the period from 1991.  Even when arguing under ground (f) that it would be excessive to uphold all the requirements of the notices, it was not contended that there existed a fall-back position of previously established lawful use in respect of any specific activities.  Accordingly what the inspector says is an accurate reflection of the way the case was put to him; and he dealt with the matter sufficiently in the circumstances.
88.	On this issue, too, I accept Mr Mould's submissions.  It is unsurprising that the inspector found that there had been at least 10 years continuous use of the site for hay and straw dealing and agricultural contracting, since the point was common ground between the parties.  He was entitled, however, to limit his findings to that point.  He seems to me to have been justified in his view that no corresponding case had been advanced in relation to any other specific use.  The 45 or so witness statements were ultimately relied on by the appellant in relation to the general issue of absence of material change of use rather than in support of any such specific case; and the inspector's handling of the issue of material change of use shows that he had them clearly in mind.  It was not unreasonable for him to conclude that the evidence of the appellant's planning expert, which again he had clearly in mind, did not amount to a case of previously established lawful use in respect of any specific uses.  The matter was simply not argued in that way in the appellant's closing submissions.  In the circumstances the inspector cannot fairly be criticised for dealing with the matter as he did.
89.	I should record for completeness that in my view the inspector plainly appreciated that the 10 year period for determining whether a lawful use had been established was not limited to the 10 years immediately preceding the application.  That is clear from paragraph 104 of his decision.  The last sentence of paragraph 105 does not disclose any different or mistaken understanding of the test.
(4) The Notice A appeal issue
90.	Notice A related to the works carried out to units 9 and 10 in 1998.  The breach alleged was "the addition of block work and cladding to, and the re-roofing of, former open sided agricultural barns resulting in the new building (Units 9 and 10) shown … on the plan".  This was said to be operational development carried out without planning permission.  The inspector dismissed the ground (a) appeal against Notice A, finding that the works constituted inappropriate development in the Green Belt and that there were no very special circumstances that outweighed the presumption against such development.
91.	Mr Clay submits first that if the appellant succeeds on the second bite issue or the material change of use issue, it would be right to remit the Notice A appeal to the Secretary of State at the same time in order to permit him to reconsider the ground (a) issue concerning operational development.  I do not see why that should follow; but having decided that, subject to any further submissions on discretion, the appeal should succeed on the second bite issue, I will if necessary hear further submissions as to the consequences for the Notice A appeal.
92.	Mr Clay submits that in any event the inspector erred in two respects in reaching his conclusion on the Notice A appeal.
93.	The first point concerns the question whether the works were permitted development within the Town and Country Planning (General Permitted Development) Order 1995, or would have been permitted development but for one technical point concerning the proximity of the land to an aerodrome.  The inspector stated in paragraph 119:
“119. There was some confusion about whether or not the building and its extension could have been erected as ‘permitted development’ for agricultural purposes and although the Council may have wrongly told the appellant this was the case at some time in the past, it was agreed that the buildings could not be permitted development due to the proximity of the site to an aerodrome and the size of the building involved.  The appellant admitted in his evidence that it was formed from second hand industrial rather than agricultural buildings but I agree that currently there is little difference, with the same profiled steel sheeting often used for the cladding and roofing on both.”
94.	It is submitted that he should have made a positive finding in the appellant's favour.   It is not in issue that agricultural use of the land is lawful.  On that basis, the inspector should have considered whether the works were permitted development under Part 6 of Schedule 2 to the 1995 Order, where permitted development under class A is defined as:  "The carrying out on agricultural land comprised in an agricultural unit of 5 hectares or more in area of - (a) works for the erection, extension or alteration of a building … which are reasonably necessary for the purposes of agriculture within that unit".   It is true that paragraph A.1(e) provides that development is not permitted by class A if "the height of any part of a building, structure or works within 3 kilometres of the perimeter of an aerodrome would exceed 3 metres", which was the case here.  But the inspector ought to have considered whether, but for that point, it would have been permitted development and, if so, whether the proximity to the aerodrome was in practice a good reason for refusing planning permission.
95.	I accept Mr Mould's submissions that such reliance on the 1995 Order is unsustainable for several reasons.  First, the land was not in agricultural use at the relevant time, but was in mixed use including the various commercial activities found by the inspector.  The provisions of Part 6 of Schedule 2 to the 1995 Order, which relate specifically to agricultural buildings and operations, had no application to land in such mixed use.  Secondly, it was not contended before the inspector, and there was no evidence before him, that the works were "reasonably necessary for the purposes of agriculture" within the unit.  Thirdly, once it was accepted that because of proximity to the aerodrome the works could not amount to permitted development, it was not necessary for the inspector to consider the matter in terms of the 1995 Order.  Fourthly, there was, unsurprisingly, no suggestion before the inspector that the building should be allowed to remain because of a reasonable need for it as an agricultural building (see in particular paragraph 153).
96.	The second point raised by Mr Clay, though it was not in the claim form or skeleton argument, is that the inspector applied the wrong test under s.55(2)(a).  That provision excludes from the scope of development the carrying out of works of alteration etc. which (i) affect only the interior of the building, or (ii) do not materially affect the external appearance of the building.  That is a disjunctive test.  In paragraph 125, however, the inspector expressed it as a conjunctive test, using "and" instead of "or".  He said:
“… I agree that the definition states that it is not development if works for the maintenance, improvement or other alteration of a building are works which firstly, affect only the interior of the building and secondly, do not materially effect [sic] the external appearance of the building.”
97.	Again I accept Mr Mould's submissions in response to that point.  Even if the inspector was technically in error in referring to the statutory test in conjunctive rather than disjunctive terms, it gets the appellant nowhere on the facts since the inspector went on to explain in paragraph 126 why in his view the works did not affect only the interior of the building and did materially affect the external appearance of the building.  Thus neither limb of s.55(2)(a) was satisfied and nothing turns on whether a disjunctive or conjunctive approach was applied.  
98.	Subject, therefore, to the implications of the appellant's success on the second bite issue, the appellant's case in relation to the Notice A appeal fails.
(5) The deemed planning permission issue
99.	In his decision the inspector rejected an argument by the appellant that the combined effect of s.173(11) and an enforcement notice issued in 1996 had been to confer deemed planning permission in respect of the uses that the 1996 notice did not require to cease.
100.	I have already set out the terms of s.173(11).  It applies where an enforcement notice in respect of a breach of planning control "could have required any buildings or works to be removed or activity to cease, but does not do so" and all the requirements of the notice have been complied with.  In those circumstances, then "so far as the notice did not so require, planning permission shall be treated as having been granted … in respect of development consisting of the construction of the buildings or works or, as the case may be, the carrying out of the activities".  
101.	The 1996 notice was expressed to relate to the whole of the site.  The breach of planning control alleged was:  "Without planning permission, change of use of the said land from use for agriculture to a mixed use for agriculture and an engineering contractors' depot involving the storage of plant, equipment, materials, vehicles, portable buildings and machinery".  What the appellant was required by the notice to do was:  "(i) Cease the use of the land for an engineering contractors' depot. … (ii) Remove from the land all plant, equipment, materials, vehicles, portable buildings and machinery used or stored in connection with the use of the land as an engineering contractors' depot …."
102.	The notice was appealed on a number of grounds.  At the inquiry it was made clear by counsel for the council that the notice was concerned only with the use of the site for what has been described as "the McNicholas use", namely use as a depot for vehicles and equipment during cable laying operations in the area by a contractor called McNicholas.  There were various adjournments and indications were given of an intention by the council to amend the notice to cover other operations taking place on the site.  In the event, however, the appeal was withdrawn for a number of reasons, the principal of which was the council's assurance that the notice was directed only at the McNicholas use, which had in fact long ceased.
103.	The submission made by Mr Clay on the basis of those facts is that the effect of s.173(11) was to confer a deemed planning permission on all other uses of the site existing at the time of the 1996 notice.
104.	The first and in my judgment insuperable hurdle faced by that submission is the decision of the Court of Appeal in Scott v. Secretary of State for the Environment, Transport and the Regions (unreported judgment dated 16 October 2000, on appeal from the first instance judgment reported at [2000] JPL 833).  That decision makes clear that s.173(11) applies only to uses of the land which are alleged by the enforcement notice itself to be in breach of planning control.  If a use is not alleged to be in breach of planning control, then the notice cannot require the use to cease and deemed planning permission cannot arise out of the failure of the notice to require the cessation of that use.  The provision therefore has no application to uses that are not alleged by the notice to be in breach of planning control.  As it was put in paragraph 15 of the judgment of Schiemann LJ:
“…  The enforcement notice manifestly did not allege that construction of the culvert had been carried out in breach of planning control.  In those circumstances the enforcement notice could not have required the removal of the culvert.  In those circumstances section 173(11) is not in play and there is no question of any deemed planning permission for the culvert  ….”
105.	Mr Clay seeks to bring the appellant's case within the scope of the reasoning in Scott by contending that the breach of planning control alleged in the 1996 notice was the entirety of the mixed use of the land, the true nature of which was known to the council at the time, but that the council chose by the notice to require cessation only of the McNicholas use.  Accordingly, he submits, there was under-enforcement of a kind to which s.173(11) applies and the balance of the mixed use benefits from deemed permission.
106.	In my view the 1996 notice is not to be construed in that way.  The "mixed use" alleged by the notice to be in breach of planning control was limited to agricultural use plus the McNicholas use, rather than the entirety of the activities on site (and as comprised, for example, within the mixed use alleged in Notice I); and there was a direct correspondence between the breach alleged and the requirement to cease the McNicholas use.  That was also the basis upon which the parties proceeded.  The council made clear that the notice was directed only at the McNicholas use (there being no objection to agricultural use), and that was one of the reasons why the appeal against the notice was withdrawn.  Even if there was a vagueness or ambiguity in the wording of the notice, the fact is that the parties proceeded on the basis of a narrow construction; and the present submission that the notice was directed to the entirety of the activities on site and that everything but the McNicholas use should therefore gain the windfall benefit of deemed planning permission runs counter to the position accepted in practice by the appellant at the time. 
107.	In his skeleton argument Mr Clay also relied heavily on paragraph 2.10 of Circular 10/97, which deals with s.173(11).  Some of the language in the paragraph suggests that deemed planning permission is conferred by s.173(11) on "all the remaining uses or activities" on the land save those the cessation of which is required by the enforcement notice.  This could be taken to indicate a broader construction of the provision than that adopted in Scott.  Mr Mould accepted that the paragraph was confusing or ambiguous in part, but rightly submitted that the circular cannot affect the construction of s.173(11) or detract from the effect of the decision in Scott.  No doubt consideration will be given to improving the text of the circular so as to reflect the decision in Scott more clearly.
108.	Those observations on the circular do not affect my rejection of the appellant's case on the deemed planning permission issue.
Overall conclusion
109.	For the reasons given, I find in favour of the appellant on the second bite issue alone.  As indicated, I will hear from counsel on questions of relief.