England and Wales High Court (Technology and Construction Court) Decisions

IN THE HIGH COURT OF JUSTICE
QUEENS BENCH DIVISION DIVISION
LEEDS DISTRICT REGISTRY
TECHNOLOGY AND CONSTRUCTION COURT

		The Court House Oxford Row Leeds LS1 3BG
		5 April 2016

 


Introduction

1. The Claimants, Sydney and Angela Bell own and reside at Dene Lodge, Elmfield Terrace, Hampeth, Northumberland. To the east of their home and outside the boundary of their land there runs a small stream or burn called Ogle Letch. It lies at the bottom of a fairly steep slope. The material of which the slope, and indeed the whole area, is comprised is Glacial Till. A layman would recognise it as clay. It is common ground that the slope is unstable and there is slippage of material from it into the burn.
2. This is a major concern to the Claimants. They contend the slippage has already removed support from their garden with the result that it has started to slope towards the burn and they fear that eventually, as more landslip occurs, not only their garden but their home itself will be deprived of the support it now enjoys from the land upon which it is sits and it will itself subside into the burn.
3. In about 1926 a combined sewerage pipe was constructed from a sewage treatment works adjacent to a colliery downstream of Dene Lodge (and broadly to the south of it) to a row of miners’' houses on Beacon Road, upstream of Dene Lodge and broadly to its north. A combined sewer is one that conveys both foul water and rainwater.
4. Before significant lengths of this sewer were abandoned as a result of diversion works undertaken by the Defendant in 2010 it (or plastic pipes replacing or bypassing part of it) served the Beacon Road houses and, the Claimants contend, a further row of miners’' houses called Elmfield Terrace. This latter row of houses lies just to the south of Dene Lodge and is separated from it only by a small access road.
5. In fact the Defendant does not accept that sewage from the houses on Elmfield Terrace discharged directly into the sewer serving Beacon Road. It contends that there was a separate public sewer that served the Elmfield Terrace properties and transported their sewerage to the treatment works. In his opening note, Mr James Medd, counsel for the Defendant, referred to the sewerage pipe that served the Beacon Road properties as “"The Pipe”" and that serving Elmfield Terrace as the “"Elmfield Terrace Sewer”". There is thus a fundamental difference of view between the parties. The Claimant asserts that there is only one sewer running from the Beacon Road houses to the treatment works and into which the sewerage from Elmfield Terrace discharges, the Defendant asserts that there are 2 separate sewers.
6. Dene Lodge was constructed as a detached bungalow in the early 1980s, well over half a century after the construction of the terraced houses on Elmfield Terrace and Beacon Road. At the time of the construction of Dene Lodge a sewerage connection was made from the home into the pipe from Beacon Road rather than the Elmfield Terrace Sewer. ^[1].
7. An extension was built to Dene Lodge in the mid 1990s. Both the original house and the extension sit on the firm clay or Glacial Till characteristic of this area of the country. There are also a couple of other structures used by Mr Bell close to a point where the slope drops down to the burn. One is called Syd’'s Wood Garage which has specifically featured in the evidence.
8. It is not in dispute that, by virtue of s179(1) Water Industries Act 1991, such sewerage pipes as there were, whether it be 1 or 2 now vest in the Defendant and that pursuant to s94(1) of the Act the Defendant is under a statutory duty to maintain the pipe(s) to ensure that the area over which it has responsibility as statutory undertaker is effectively drained and sewerage is effectually dealt with.
9. Mr John Collins of counsel represents the Claimants. He asserts on their behalf that the cause of the collapse of the slope is the escape into the slope immediately to the east of Dene Lodge of sewage/water from the Pipe (or what remains of the Pipe following its abandonment in 2010 as a result of the diversion works I have referred to above) and from subsurface fluid that has been conveyed along the trench in which the Pipe was originally constructed. The trench itself, it is contended forms a channel ^[2] by which subsurface fluid is directed into the slope abutting the Claimants’' property. The result is that the slope abutting the Claimants’' property has become saturated. This has in turn reduced the shear strength of the clay and thus the stability of the slope. It is contended that the reduced shear strength caused by saturation due to the presence of the Pipe and the trench has caused a series of rotational shears and that, unless something is done, more will follow further threatening the Claimants’' garden and ultimately their bungalow.
10. The contention therefore is that the instability of the slope is the fault of the Defendant in not maintaining its pipes and in failing to have an adequate system in place to recognise failure of the pipe and failing to rectify problems when they occur. The Claimant contends that the Defendant is accordingly liable for the cost of stabilising the slope and compensating them for the losses they have suffered as a result of the landslips that have occurred so far as a result of that instability.
11. As Mr Collins points out in his closing submissions, although in the Particulars of Claim the action is founded upon nuisance and/or negligence, it is in reality a claim in nuisance. It is premised on the basis that the Defendant has caused subsidence to land adjoining that of the Claimant and that subsidence has in turn caused the subsidence of the Claimants’' land and is likely to cause yet further subsidence to their land. The subsidence has resulted in the withdrawal of the support of the Claimants’' land to which the Claimants are entitled. It is contended that the subsidence is the result of the negligent failure of the Defendant to take reasonable precautions to prevent it.
12. Mr Collins recognises that he is faced with the additional complication that the claim of the Claimant is one step removed from the usual nuisance scenario. Usually, in an action based on nuisance caused by the undermining of support for the claimant’'s land, the defendant will be accused of causing subsidence directly to the claimant’'s land. Here the subsidence alleged is actually to land not in the ownership of the Claimants. The claim is based on the knock on effect of the subsidence allegedly caused by the Defendant to the slope which is in the ownership of a third party.
13. In its defence and indeed in Mr Medd’'s skeleton argument, it is clear that the Defendant takes a limitation point arguing that at least a major part of the slope failure occurred prior to 22 August 2007. Proceedings were instituted in December 2013 but there was a standstill agreement which protected the Claimant from a limitation defence for the period from 22 August 2007.
14. Furthermore, it is argued by the Defendant first, that the Claimants have no private law right of action against it for a breach of its statutory duty but that secondly, even if they do then there has been no negligent failure on the part of the Defendant in its management of the pipe either in terms of its maintenance or in terms of remedial works. Mr Medd argues that, albeit this is a claim in nuisance, the usual strict liability for nuisance does not apply. He cites Marcic v Thames Water Utilities Ltd (2003) UKHL 66, as authority for his propositions. He argues that that case established first, that a statutory sewerage undertaker is not liable at common law for nuisance where liability would be inconsistent with a statutory scheme for enforcement and secondly, that even if a statutory undertaker is liable in nuisance for its activities undertaken pursuant to statute (as here pursuant to s94 of the Water Industry Act 1991) then liability would not arise on a strict liability basis but only if fault is established. Furthermore he argues that remedial works were undertaken by reputable and competent subcontractors for whom the Defendant is not vicariously liable and he argues still further, that in any event nothing emanating from the pipe or the trench in which it sits (or once sat) has caused the slope at the bottom of the Claimants’' garden to fail. This latter point is Mr Medd’'s causation defence and it is on this issue that the case and the expert evidence has been predominantly focussed.
15. This is not to say that the Defendant does not accept that the sewerage pipe was in poor condition and that from 2001 there was from time to time leakage from it. It accepts that running repairs have been carried out on the pipe from 2001 on a fairly regular basis. In 2008 a fairly large scale (and not wholly successful) temporary repair was undertaken pending a permanent solution. That solution, undertaken in 2010, was the abandonment of part of the pipe and the rerouting of sewage under the roadway to the west of Dene Lodge and Elmfield Terrace. The point made by the Defendant is that it was movement in the slope that caused the pipe to fail and leakage to occur, not the other way around. Further, that in any event the minimal leakage into the ground that was caused by pipe failure was not a cause of the underlying instability of the slope. That has been caused by other factors in particular, the presence in the slope of rainwater discharging from a highway drain running to the south of the property, rubble and other made ground that has been dumped onto the slope (including directly over the pipe), water run off from the pavement of Beacon Road adjacent to Dene Lodge and the fields to the north much of which water is captured by a drainage channel constructed by Mr Bell to the north of the property and which discharges onto the slope, a general rise in the water table in this area due to rainfall and finally, erosion caused by the outside of a bend in the path of the burn.
16. In addition it is denied, as contended by Dr Reeves, the chartered geologist and chartered environmentalist instructed by the Claimant, that the trench into which the pipe was placed during construction is channelling subsurface fluid into the area afflicted by this instability. It is common ground that for that to occur there would need to be a permeable drainage pathway around the pipe through which water would inevitably run since it would be its line of least resistance. Dr Reeves called it the subsurface fluid’'s “"preferential pathway”"
17. In the Particulars of Claim it is contended that the permeable drainage pathway is gravel and sand with which the trench was backfilled at the time of construction together with disturbed excavated material. In fact, as I understand the oral evidence of Dr Reeves, his position may have shifted somewhat. His oral evidence seemed to focus on the contention that the permeable material is confined to the clay that was disturbed and broken up when excavated for the purpose of building the trench and which was then used as backfill. His point was that the fact that that material had been excavated and inevitably disaggregated made it more permeable than the undisturbed, compacted clay of which it originally formed part and it provides a preferential pathway for the subsurface fluids. I deal with this in more detail below.
18. Dr Jones, the geotechnical expert instructed by the Defendant does not accept that the clay in the trench that surrounded the pipe provided (or now provides) a preferential pathway. His view was that it will have been compacted by the original constructors of the sewage pipeline and that it will have become further compacted over time. In any event, it is not accepted that any fluid directed to the unstable slope by this process is of the volume to cause or contribute to instability especially when compared to the volume of moisture coming into it from other sources.
19. This hearing over 4 days was confined to liability and causation. Quantum and the scope of any remedial scheme will be the subject matter of further directions if this hearing results in judgment for the Claimant.

Limitation

20. As Mr Medd puts it in paragraph 7 of his written submissions the claim is statute barred if the Claimants fail to establish first that the state of the pipe and the trench and their contents have, since 22 August 2007, constituted a fault based nuisance upon which the Claimant can rely (bearing in mind, as I mentioned in paragraph 12 above, that they are one step removed from the nuisance) and secondly, that they have suffered damage to their property since 22 August 2007.
21. However at paragraph 7.3 of his written submissions Mr Medd accepts that within the limitation period there has been some landslip of the slope adjacent to Syd’'s Wood Garage. The allegation by the Claimants is that this landslip is the result of the saturation of the slope as a result of the presence and condition of the Defendant’'s pipe and trench and that the Defendant is liable to the Claimants for it in fault based nuisance. The contention is that the Claimants have suffered damage by this subsidence because, albeit it is not on their land, it has removed, or at least undermined, support for their land. They allege a cause of action that arises within the limitation period. This is because, whether or not there has been subsidence in the period before August 2007, each successive subsidence gives rise to a fresh cause of action.^[3].
22. In any event, Mr Medd faces the difficulty that the allegation is that the presence of the pipe and the trench is still contributing to the instability of the slope and thus, by extension, the integrity of the Claimants’' property. Indeed I am told there was a significant landslip a matter of days before this case was heard. The Claimants’' contention therefore is that there is a continuing nuisance. In this respect Mr Collins in his final submissions cites the observations of Parker J in Jones v Llanrwst UDC 1911 Ch 393 at 411

“"I do not think that in the case of a continuing nuisance … the Statutes of Limitations have any application except as to the amount of damages to be recovered”"

23. In the light of Mr Medd’'s sensible observations in paragraph 7.3 of his written submissions and what I have set out above I do not think that I need dwell on the issue of limitation and I conclude that this claim is not statute barred.

Does the Defendant have a relevant duty?

24. The starting point in the search for the answer to this question is Marcic to which I refer in paragraph 14 above. I have already set out there the principles established by that case in regard to the absence of a cause of action in nuisance for a member of the public against a statutory sewerage undertaker where the statute itself includes an enforcement scheme. There is no doubt that the 1991 Act incorporates such a scheme. The Act provides for the issuance of an enforcement notice by the Director of the Water Regulator, Ofwat when he/she is satisfied that a sewerage undertaker is contravening a statutory requirement enforceable under s18 of the 1991 Act.
25. As was said by Lord Nicholls in Marcic (paragraph 35)

“"The existence of a parallel common law right, whereby individual householders who suffer sewer flooding may themselves bring court proceedings when no enforcement order has been made would set at nought the statutory scheme. It would effectively supplant the regulatory role the director was intended to discharge when questions of sewer flooding arise""

26. In this case there has been no enforcement order.
27. Marcic was followed in Nicholson v Thames Utilities Ltd (2014) EWHC 4249 where the claimant had suffered an ingress of sewage into her home because a public sewer had become blocked by tree roots. It is also right to observe that in that case the Defendant employed a reactive maintenance scheme summarised by Knowles J in that case from paragraph 11 as follows;

“"Thames Water does not have any programme to check for tree roots or other problems with sewers in its area, not even a gradual or targeted one. Instead it waits until defects have been reported by others, including the public, and then it acts.

This approach makes inevitable the type of experience Ms Nicholson had. Only if a defect has been encountered early and reported by the public or the highway authority might an experience of the type she had be avoided.

Views will differ on the question of whether that reactive system is good enough. However in light of the scheme of the 1991 Act, as explained in Marcic that is not a question for this Court to judge in litigation such as the present.”"

28. I also observe that counsel for the Claimant in Nicholson conceded that allegations of negligence relating to the care with which the sewers were maintained “"were not allegations upon which the Claimant could succeed”". I should add that negligence was pleaded and pursued in that case on the alternate basis that the Defendant had specifically assumed towards that Claimant a responsibility sufficient to ground a case in negligence under the principles enunciated by Lord Hoffmann in Gorringe v Calderdale MDC (2004) 2 All ER 362.
29. In his final submissions (paragraph 2) notwithstanding that the claim is pleaded in negligence as well as nuisance Mr Collins makes it clear that this case is one of nuisance (subject to a point concerning s180 and Schedule 12 para 4 of the 1991 Act)
30. At first blush on the basis of Marcic and of Nicholson it would seem that the Claimants must essentially fall at the first hurdle namely that there is no cause of action open to them. However in Dobson v Thames Utilities Ltd (2007) EWHC 2021 TCC Marcic was considered at length.
31. In that case the Claimant sought to hold the Defendant liable in nuisance for the odours and mosquitoes emanating from their sewage treatment works. It was held by Ramsey J that the principle in Marcic will not protect the Defendant from liability at common law if the nuisance resulted not from a mere lack of capacity in the sewage system but from a negligent failure at an operational level (my emphasis) adequately to discharge their statutory responsibilities to clean and maintain the sewers.
32. At paragraph 148 Ramsey J said thus;

“" Whilst the principle in Marcic’'s case precludes the claimants from bringing claims which require a court to embark on a process which is inconsistent and conflicts with the statutory process under the 1991 Act, it does not preclude the claimant from bringing a claim in nuisance involving allegations of negligence where, as a matter of fact and degree, the exercise of adjudicating on that course of action is not inconsistent and does not involve conflicts with the statutory process under the 1991 Act""

33. As to the matter of fact and degree, inconsistency and conflict, he had this to say;

“"Policy matters were likely to lead to such inconsistency and conflicts and operational matters were less likely to do so. It must be a question of fact and degree. Where an allegation is tantamount to requiring major plant renewal that will fall on one side of the line whilst an allegation that a filter should be cleaned will lie on the other side of the line”"

34. The learned judge found in that case that the Defendant owed the Claimant a duty in common law nuisance. It was a first instance decision which went to appeal but not on this point.
35. As Mr Medd points out, if Dobson is to be followed (and he says that in this regard it is obiter) the issue here is whether the action that the Claimant argues that the Defendant ought to have taken to abate this alleged nuisance was operational in which case a cause of action will lie or strategic and would involve the court getting involved in a process that is inconsistent with the statutory scheme, in which case it falls on that side of the line where a claim in nuisance cannot succeed.
36. I do not accept that Ramsey J’'s conclusions were obiter. It seems to me that the issue of whether in that case, on Marcic principles, the Claimant was precluded from bringing an action was specifically one of the preliminary issues that the learned judge had to consider.
37. I am of course not bound by it but it is the decision of a High Court Judge reached after a comprehensive analysis and is furthermore a conclusion which was not appealed. It is highly persuasive and I see no reason not to follow it.
38. Applying those principles I am satisfied that in general terms the matters about which the Claimant complains fall on the side of the line that permits an action to lie. Broadly what are those matters? They are that the Defendant failed to maintain the pipe or adequately repair defects in it. In the circumstances of this case I am satisfied that in general terms these are operational in nature rather than what I have termed “"strategic”". They are more akin to cleaning a filter than major plant renewal.
39. I say in general terms because one of the Claimant’'s complaints is that it took 3 years from 2007 to 2010 to put into effect a permanent solution to the alleged leakage from the pipe. I set out the details of that solution in paragraph 15 above. Mr Medd says that that involved the replacement of a sewer and as such cannot be seen to be operational. It is a big job rather than what might be seen in context as a tinkering job. I agree but in fact it is difficult to see how a finding either way in respect of that issue would alter the outcome of this case.

Is there strict liability for the nuisance or does it have to be fault based?

40. I need cover this only very briefly. As I understand Mr Collins submissions, he accepts that he needs to establish fault. In the light of the principles set out in Marcic it seems to me that a contrary view would be untenable.

Independent Contractors

41. The Defendant argues that when first advised in 2001 of possible leakage from the sewer pipe and at all times thereafter it relied on independent contractors to advise on solutions and carry them into effect. It was for example independent contractors who designed remedial schemes, decided not to remove the whole of the pipe and trench that was abandoned when the sewage was rerouted along the roadway and undertook grouting of abandoned pipework.
42. Mr Medd argues that these are not non delegable duties and the contractors are entirely independent and there is no relationship between the Defendant and the contractors akin to the employer/employee relationship by which the Defendant can be fixed with vicarious liability.
43. He cites NA v Nottingham CC (2015) EWCA Civ 1139 which applied the principles set out in Woodland v The Swimming Teachers Association (2013) UKSC 66. In NA it was concluded that a local authority was not vicariously responsible to a child in care for cruelty and sexual assaults perpetrated on her by her foster parents and nor did it owe her a non delegable duty of care to protect her from harm.
44. Mr Collins on the other hand argues that in this case what the Claimants complain about is nuisance by reason of the withdrawal to support for their land. He argues at paragraph 5 of his final submissions that

""it matters not whether the defendants themselves by their actions cause subsidence or whether they employ contractors … their duty was to prevent their sewage plants becoming a nuisance. How they accomplish that was immaterial""

45. Clerk and Lindsell 21^st Ed paragraph 20-72 deals with nuisance created by an independent contractor. It states

“"Whether a person can be said to be a wrongdoer if the nuisance is created by an independent contractor depends on whether he could reasonably have foreseen that the work he had instructed the independent contractor to do was likely to result in a nuisance”"

46. At paragraph 20-73 the editors discuss the scope of the principle. Their conclusion, based upon principles enunciated in Salsbury v Woodland 1970 1QB 324, is that to impose on the occupier general vicarious liability for a contractor’'s negligence the work must involve some special risk or hazard or be in discharge of some positive and continuing duty.
47. However, I am not concerned here with a nuisance created by an independent contractor, I am concerned with an alleged nuisance that arose irrespective of their involvement but which at best they failed to abate. If they fail to abate it then the nuisance (if there is one) continues. In my view, subject to Marcic principles and other exceptions that may protect a public body, so long as a nuisance continues the person affected by it is entitled to look to the creator of that nuisance to stop it and to seek redress from him for so long as the nuisance exits and for its consequences.
48. I am fortified in that view by the decision in the House of Lords in Sedleigh Denfield v O’'Callaghan 1940 AC 880 and the speech of Lord Atkin

“"the Defendant clearly continued the nuisance for they came clearly within the terms that they knew the danger, they were able to prevent it and they omitted to prevent it”"

49. In my view NA and Salsbury (which involved a claim arising from the harm suffered by the Claimant who was inadequately looked after in a swimming pool), can be distinguished. They involved a contractor who itself created the problem. Unlike here, where, if the Claimants are right, the nuisance existed absent the involvement of any contractors and all that can be said is that the contractors failed to abate it.
50. Accordingly, I find that the Defendant is unable to avoid liability merely because they used independent contractors.

Does a claim lie in nuisance for withdrawal of support where the land immediately affected is not owned by the Claimants?

51. I have to say that this is not a matter which Mr Medd addresses in his submissions but it is a matter upon which Mr Collins touches. He prays in aid again the judgment of Parker J in Jones v Llanrwst UDC referred to above in which the judge said that

“"The duty of the owner of a sewer at common law will be to see that the sewage in his sewer does not escape to the injury of others and mere neglect of this duty would give the person so injured a good cause of action.”"

52. The Claimants do indeed argue that sewage (and water) has escaped to their injury. On that basis it would not matter that the injury is not caused directly by the sewage but by its effect on land which offers support to their land. However caused, the allegation is that the escape has caused them injury.
53. In the absence of any submissions that would suggest that the existence of an intervening step is fatal to this claim I am not minded to find that no action lies just because the Claimant do not own the land directly affected by any leakage.

S180 1991 Act and Schedule 12 paragraph 4

54. Initially in the Particulars of Claim the Claimants pleaded that s209 of the Act gave rise to a strict liability on the part of the Defendant to the Claimants. In his opening note (paragraph 16) Mr Collins accepted that that did not apply in this case.
55. S180 of the Act however does impose the obligation on an undertaker to pay compensation in the circumstances set out in Schedule 12 to the Act. Paragraph 4 of that schedule deal with compensation in respect of sewerage works.
56. This is not without its significance. If a statutory body is obligated by the statute to pay compensation this is a basis for contending that a private law cause of action can lie against it. One might have thought that the wording of paragraph 4 of Schedule 12 may open the way for a claim for compensation but at the outset of the case Mr Medd argued that that is not how the schedule has been interpreted and Mr Collins did not demur from that. Accordingly I was told by Mr Collins that it was accepted that there was no statutory provision in the Act which gave rise to a civil liability in the circumstances that pertain to this case.
57. In his final submissions at paragraph 10 Mr Collins rows back somewhat from that. It seems to me however that he has not rowed back very far. He merely says that he thinks that such a claim is “"arguable”" but that “"the damage sustained by the Claimants is quite small”" and that in any event the “"statutory scheme does not cover the problem thrown up by the events in this case”"
58. In the light of those observations and in the absence of any of the arguments that apparently make it arguable I am not minded to consider further the effect of the schedule. In any event, in the light of my finding that essentially the claim is justiciable, there is little reason to do so.

Remaining Issues

59. Having dealt with what are questions of law I am able to turn to a central issues in this case and upon which essentially the claim actually stands or falls namely causation. ^[4]. The first pivotal question is whether the state of the pipe, or its remains and/or the alleged trench and fluid therefrom have caused the slope to slip and/or are continuing to do so. There is an additional hurdle however for the Claimants even if the causation issue is resolved in their favour. For the reasons set out above they must establish fault on the part of the Defendant.

Causation

60. As both Mr Collins and Mr Medd recognise, causation will essentially be determined on the basis of which expert I find to be the more persuasive. If I prefer the evidence of Dr Reeves then causation is established, if I prefer the evidence of Dr Jones then the Claimants fail.
61. I heard from a number of factual witnesses. In this context some of their evidence will feed into the analysis of which expert is the more convincing but much of it will not.
62. It is as well to deal with this evidence briefly at this point. I do not intend to deal with every aspect of their evidence but only that touching on causation. I have read their statements and taken a careful note of their oral evidence and the analysis of the same by both counsel in their written submissions.
63. It is as well to consider this evidence in the context of the chronology. Both Mr Collins and Mr Medd have helpfully attached one to their skeleton arguments and, whilst they are not identical, in many respects the differences are immaterial. I include only those events that are relevant to causation

June 1980	Construction of Dene Lodge begins
March 1995	Construction of the extension to the north of the existing property commences begins
3 May 2001,	Mrs Bell telephoned Sandra Hutton, an operative at the Defendant customer call centre. There is a computer note of that conversation. It states as follows “"Urgent – at back of the garden area sunken-thought due to rain but now found raw sewage leaking and running into burn at the rear
4 May 2001	A repair was undertaken by Graydons, a firm of contractors on the Defendant’'s list of approved contractors. The repair consisted of the installation of 5 metres of plastic pipe into the existing sections of the sewer pipe.
3 March 2003	Mrs Bell telephoned the Defendant again. This time she spoke to Valerie Thompson another operative employed at the call centre. Mrs Thompson records that “"mrs (Bell) rang to confirm sewage running into the burn again see prev notes. Last time there was a sewage collapse due to landslide please can we ask the rep to check this out”"
27 September 2007	The sewer pipe fails in that there is no flow detected to the sewage treatment works. The sewer is found to be in poor condition
28 September 2007	CCTV survey and temporary repair undertaken by Graydons
1 October 2007	Further CCTV survey
5 October 2007	Graydons carry out further repairs
15 October 2007	Further repairs following further leaks
18 October 2007	The Defendant record that the Claimants’' garden is falling away
25 October 2007	Graydons install plastic piping from rear of Dene Lodge to the sewage works
7 February 2008	Entec (a further contractor) visits the site
13 February 2008	Entec reports to the Defendant
11 February 2008	Mrs Bell calls the Defendant to report that drain is backing up
22 February 2008	The Defendant install a temporary fix to the backing up drain
27 February 2008	Entec recommend diversion of the sewer
May 2008	Temporary pipe installed
1 December 2008	Further leak from temporary pipe
26 April 2010	Further leak reported. The Defendant’'s employee who attends on site reports further ground movement
27 April 2008	Graydons carry out repair
20 September 2010	Permanent remedial work involving diversion of part of the sewer under the roadway commences
Jan/Feb 2011	Grouting work to abandoned pipe carried out

The Claimant’'s Lay Evidence

Mr Sydney Bell

64. He said that he noticed that the land was slipping in 2007. The report written by Sandra Hutton following her conversation with Mrs Bell on 3 May 2001 referred to in the chronology would suggest that he is mistaken but Mrs Bell disputes the veracity of that statement.
65. He acknowledged that the line of the Pipe running from the Beacon Road terraced houses is as per the plan attached as exhibit NH1 of the witness statement of Mr Neil Howiston and that it runs down to a manhole known as 5701 and from there along a line to the east of Dene Lodge but close to its boundary, underneath Syd’'s Wood Garage and then down to the sewage works. Its path is in effect towards the lip of the slope running down to Ogle Letch rather than the middle of that slope, much less the foot of it.
66. As for Dene Lodge, this was a self build project. He argued that albeit the terrain on which the property was built was generally sloping from the North West to the South East, the benching of the house into the slope was not extensive and excavated material was not excessive and was not deposited in the back garden i.e. the area to the east of the bungalow and the west of the top of the slope. Nor he said, was it necessary to excavate the back garden because that was quite flat and so no made ground had to be applied to it to level it off.
67. This is not accepted by Mr Medd. He argues that Mr Bell has understated the amount of excavation needed for the benching of the house and the levelling of the garden in order to confront the contention that the slope has been put under pressure by the weight of this made ground. Mr Medd points out that Mr Kenneth Johnson, one of the Claimants’' own witnesses, accepted that the ground level in the front garden is about 2.5 metres higher than in the back garden. That is, he argues, a significant slope which will generate significant arisings as a result of the benching process and that significant earth will be needed to achieve levelling of the garden area. He refers to a number of contemporaneous photographs in the bundle which support the contention that the Claimants’' land slopes quite significantly towards the burn and the steep slope that forms its bank.
68. Mr Collins argues that there is no evidence to dispute that of Mr Bell that it was unnecessary to carry out much in the way of cutting out and levelling of the hillside to enable the bungalow to be benched into it or to gainsay his evidence that the garden formed a little plateau in an otherwise sloping terrain. He argues that it would be surprising for a hill to descend in an even line.
69. With respect to him that is not the impression I get from the photos from E225 and 226. The former appears to show the footings in a position much higher than the shrubs or the shed visible in the background and the latter, while not actually showing the garden, shows a batch of breeze blocks at an angle suggesting that they rest on a significant slope in an area not far from the back garden. Drawings at A1 295 and 296 presumably made in the 1970s and showing the intended rear and south elevation of Dene Lodge also suggest that there is a significant slope.
70. I remind myself that Dr Jones thinks that trial pits dug close to the north eastern boundary of the Claimants’' land in an area affected by landslip show made ground to a depth of up to 0.5 metre which Mr Medd argues must have come from the excavations for the bungalow or its extension. I refer to paragraph 59 of his final submissions to the effect that if material was tipped onto the slope that is not good for the stability of the slope and further that it suggests that Mr Bell’'s garden is likely to comprise of a good deal of made ground which may be sinking due to no more than settlement.
71. Mr Bell was asked about rubbish visible on the slope to the Letch and the preparation of ground on which Syd’'s Wood Garage stands and which is also adjacent to an area of land slippage. At E194 is a photograph that clearly shows the garage relative to the slope and the bungalow. Syd’'s Wood Garage was built in the 1970s and was originally located in a different place, opposite one of the properties on Elmfield Terrace. When moved to its present location it was placed on a concrete base and it was built into the slope. A level platform upon which the concrete base sits was made out of hardcore. Mr Bell accepted that the garage sits at the edge of the slope and that the slope was artificially levelled to take the garage. I remind myself that the sewer pipe runs directly beneath the garage and the outfall for a highway drain that directs rainwater from the Beacon Hill area into the Letch is also somewhere below the garage.
72. Photographs at E193 and 194 and 196 draw attention to an area of made ground on the slope below and slightly to the north of the garage. Mr Bell accepted that the photographs are accurate and there is made ground in that area but not much. It is wood and other building material transported to the slope by Mr Bell’'s son in law in a 6 foot by 4 foot trailer.
73. Plates 12 and 13 at E198 suggest that the slope has been used as an area for dumping rubbish of a more general nature. The rubbish lies on the land in the vicinity of the line of the sewer pipe. Mr Bell argues that the rubbish is light and of the type that is frequently discarded by fly tippers all over the countryside. It does not have the weight to affect the sewer pipe buried in the ground even if the pipe is directly beneath.
74. He was asked about the highway drain to which I refer above. It is marked by a bold broken line on a plan at E219. His view was that it discharged into the slope abutting the Letch and about 4-5 metres above the Letch itself into an area onto which he accepted rubbish had been tipped. That is best shown by plate 11 at E196.
75. There is a drainage channel built to the north of the Claimants’' land excavated by Mr Bell in about 1995. It can be seen as a green line on a plan at E220. Mr Bell dug it out because his garden was flooding from water coming down the hill from the area of the Beacon terraced houses and from the pavement abutting the road leading up to those properties (water on the road itself was captured by the highway drain to which I have already referred). )^[5]. The ditch ends abruptly at the top of the slope down to the burn, not far from a telegraph pole that can be seen in various photographs in the bundle.
76. The telegraph pole itself figured in the evidence. In a photograph at E179 taken in 1995 it is vertical, by 2001 it was leaning quite badly as demonstrated by plate 12 at E198. It seems to be accepted that it leans because it is in saturated ground. Mr Bell’'s evidence is that other telegraph poles in similar areas do not lean like this suggesting that they are planted in firmer ground. The Claimants assert that water from this area is being directed by the pipe and the trench in which it sits down to the area directly to the east of Dene Lodge and which is suffering landslip. I was referred to photographs introduced during the trial to support that contention. They appear to show water is bubbling out of the pipe in a trial pit downstream of that area.
77. A photograph of the drainage ditch as originally constructed is at E195. It cannot have been overly efficient in capturing the run off from above because in 2014, when he was digging the trial pits that I have already mentioned, he took the opportunity of widening it into the pretty impressive channel at E205. That picture was taken in July 2014 and still shows pools of standing water in the channel. The channel still ends abruptly in the same place as did the original ditch.
78. I refer to the trial pits already mentioned. In 2014 Mr Bell dug 6 such pits at various points delineated on a plan prepared by Mr Kenneth Johnson at E89A and in each pit the pipe was found. I shall refer to the trial pits again later in the context of what the experts glean from them. At this point I merely record that when he dug trial pit A (TPA) at a point not far from the outfall for the drainage channel, it filled with water. That can be seen in plate 3 at E91. The Defendant argues that this was because the area was saturated not least by reason of the fact that for years water had been directed into this area by the drainage channel. Mr Bell argues that the water came from the sewer which was damaged in the process of excavating the pit. He says that the water cascaded out.
79. Finally, I refer to a hard standing immediately to the east of the garage, best seen on plate 3 at E191. That is some way from the lip of the slope but an area of gravel has been laid between it and the slope upon which cars are parked overnight from time to time. The gravel, Mr Bell says, is no more than 2- 3 inches deep and it lies on top of clay. He argues that the weight on the slope is minimal.

Mrs Angela Bell

80. In my view her oral evidence was directed not so much towards causation but more towards the issue of limitation and the question of when the Claimants learnt that the area was unstable such as to threaten their property and that the Defendant’'s assets were the cause of it. In view of my conclusion as to limitation for the reasons expressed in paragraphs 20 to 23 above. I do not need to dwell on her evidence.
81. I merely make two preliminary points. First, that she denies mentioning any landslip in any conversation with the Defendant’'s call centre in either 2001 or 2003 notwithstanding a note in the Defendant’'s contemporaneous computer records to the contrary. Secondly, that she says that she made 3 calls to the call centre rather than the 2 recorded by the Defendant. In the context of things generally, I do not see that determination of this issue is necessary for a proper determination of the substantive matter before me.
82. In my view the significance of her involvement with regard to the matters about which I am directly concerned is limited to her interactions with the Defendant’'s employee who came to the home from time to time. She had extended contact with Mrs Aileen Deeble who expressed her surprise to Mrs Bell about how much her land had dropped.

Mr Kenneth Johnson

83. Mr Johnson is a fellow of the Institute of Materials, Minerals and Mining, a European Engineer, a chartered engineer and a Chartered Environmentalist but there is no permission to call him as an expert in this case and I intend to confine my assessment of his evidence to that of fact rather than opinion.
84. I should record that he is on the list of vexatious litigants and he freely admitted that he stands to gain financially if the Claimants succeed. He is known to the Claimants in that he was retained by them in connection with the proper installation of the reinforced concrete foundations at Dene Lodge and the connection of their sewer pipe to the Defendant’'s pipe with which I am concerned. He was subsequently reinstructed to help them with a claim for compensation arising out of the rerouting of the sewer in 2010.
85. His written evidence is extensive but most of it in my view is evidence of opinion. I note that in his final submissions Mr Collins deals with his admissible evidence in the space of 7 lines and contends that the materiality of his evidence is broadly confined to his involvement with the trial pits and the preparation of the plan which shows, amongst other things, their location.
86. Mr Medd spent a little more time on Mr Johnson’'s evidence in his final submissions. The connection of the Claimants’' private sewer pipe to the main sewer became something of an issue in that it was suggested that the connection may have been defective in that it created the opportunity for there to be a blockage in the main sewer at the point immediately upstream of the connection if the private sewer protruded into the public sewer. The suggestion, as I understand it, was that this could cause fracture of, or leakage from, the main sewer causing ground movement. Mr Johnson could not help. He had not made the connection. He had only inspected it subsequently and such inspection would not discern the amount if any by which the private sewer protruded into the main sewer.
87. As Mr Collins points out, the connection was made by Mr Bell and there were no problems with it for many years. Furthermore it would have been inspected at the time by the NCB (who owned the main sewer at the time) and the local authority. There is reference to this issue in the written evidence of Mr Neil Howliston (paragraph 8 first witness statement) and Mrs Aileen Deeble (paragraph 33) to which I shall come shortly.
88. I should say however that in any event, my understanding is that the suggestion that this connection somehow contributed to the cause of the landslip was not actively pursued by the Defendant.

The Defendant’'s Lay Evidence

Mr Neil Howliston

89. He is a Technical Support Team Leader employed by the Defendant and is responsible with his team for the day to day running of the Defendant’'s 16000 kilometre sewer network.
90. On the issue of causation there are the observations he makes in paragraph 8 of his first witness statement and which I refer to above. At paragraph 9 he introduces a CP0 Issue Identification Form created by Aileen Deeble and which shows that the sewer has category 4 and 5 defects ^[6] in the area just north of Dene Lodge and was in very poor condition.
91. There is also the following entry for 18 October 2007

“"All land in this area where it slopes down to watercourse is falling away but leakage from the sewer will be causing further instability in the ground conditions. Edge of garden to Dene House (sic) is already falling away and the occupiers do link this to the ongoing problems with the sewer”"

92. He reports that Mrs Deeble, in her consideration of options on the Form did not consider that doing nothing was an option because;

“"sewage continues to leak, currently in 2 places from hole in bank side and from plastic pipe, causing further instability in ground conditions…”"

93. A survey undertaken by Entec, one of the Defendant’'s technical contractors, at NH4 shows the state of the pipe which is suffering defects almost all the way to the Beacon Hill Terrace properties.
94. He was taken by Mr Collins to a note taken in February 2008 by a Mr Dennis Shaw in which it was suggested that the Defendant was aware of ground movement however it is clear from the note that even then the Defendant were not convinced that they were liable for that.
95. On 7 February 2011 Mr Howliston attended a meeting on site with the Claimants after which he confirmed to them that the pipe adjacent to their property was to be abandoned and the lost ground replaced. However he recalls that it was not going to be possible to fully backfill the area from which the pipe was removed because many areas were made up of ash, brick and rubble. He himself noted while on site that there was a minimal trickle of water leaking from a section of sewer opposite the Bells’' home but it was clean water and could have been water thaw following a recent snow fall.
96. The pipe was indeed abandoned and the sewage rerouted under the roadway by the major works in 2010. His evidence was that this was a major scheme and thus not an operational scheme falling on the Claimant’'s side of the line referred to by Ramsey J in Dobson.
97. He had a view as to the proposition that the trench formed a pathway for water. He did not believe that there was any granulated material in the trench and, in common with his experience of other pipes laid at the time, it is likely that it was laid in, and backfilled with, excavated clay.
98. Finally, as regards his evidence I should mention the plan of the CCTV survey at NH1. It shows the existence of 2 pipes, the Pipe running down from Beacon Road and the Elmfield Terrace pipe.

Mrs Aileen Deeble

99. She is a Technical Support Advisor with the Defendant and had perhaps more dealings with the Claimants than anybody else at the Defendant’'s office.
100. She gives a detailed chronology in her witness statement particularly of events in late October 2007 following notification that there was actually no flow down the sewer into the sewage treatment works. She too acknowledges that an inspection of the pipe at that time showed it to be in a poor state. It is her remarks and recommendations that found their way into the Form referred to in paragraph 90 above but of course whether the leakages from the pipe or from the trench surrounding it were causing instability in the slope or the instability in the slope was causing defects in the pipe is essentially a question for the experts. As Mrs Deeble pointed out in re-examination, it is not down to her to conclude why slope failures occur. On her visits to site she was not looking for causes of ground instability, she was merely concerned with the effect of ground instability on the sewer.
101. Having said that, I do record, for completeness, that it is not disputed that in 2007 the pipe was affected by ground movement. As Mr Medd points out at paragraph 78 of his final submissions there was a collapse of the sewer near the telegraph pole but when dye was put into a manhole upstream it still discharged downstream of the area of the collapse indicating that fluid was still travelling down the pipe.
102. In 2010 there was a report of leaking sewage and Mrs Deeble attended again on site. In an email to Beatrice Bradley of 28 April she recorded that there was indeed leaking sewage and that the private sewage pipe serving Dene Lodge ^[7] had moved and come apart and there were other breaks in the main plastic pipe installed as a temporary repair in 2007. She reports that

“"it is very obvious that there has been a lot more ground movement since I last attended this site and Dene Lodge has lost more of its garden area”"

103. She too recollects that the area, particularly around Syd’'s Wood Garage, contained much rubble.

Mr Paul Kelly

104. There is no need to dwell on his evidence. In my view it does not assist me in determining causation.

Mrs Kathryn Waugh

105. As with Mr Kelly, there is no need to dwell on her evidence because it does not address the issue of causation.

Mr Amitkumar Patel

106. He is employed by Amec (formerly known as Entec) and was the project engineer [see paragraph 7 of his witness statement] for the diversion of the route of the sewer in 2010. He was responsible for feasibility studies into the various options available bearing in mind that the plan was to reroute the sewer away from unstable ground.
107. In the course of his investigations he too came to learn that the pipe was in poor condition. That was clear from CCTV footage and a geotechnical survey by a Mr Metcalf, his colleague which suggested that the failure of the pipe was most likely due to the failure of the slope, a conclusion with which Mr Patel agreed (see paragraph 20 of his witness statement).
108. The final plan for the 2010 project is that contained in plans at D1 AP6 and AP7. It involved repairing the existing sewer to a manhole A, somewhat to the north of manhole 5701 and abandoning the existing sewer from about that point. A substantial proportion of the abandoned sewer was to be left in situ but grouted and a length of the old sewer from the northern boundary of Dene Lodge to a point a little north of Syd’'s Wood Garage would be abandoned by removing from the ground. The rest of the old sewer pipe would simply be left as it was. Mr Patel explains this in paragraph 27 of his witness statement. Much of it was broken or collapsed ^[8] and so could not be grouted or plugged and much of it was under outbuildings including Syd’'s Wood Garage. It was also on an unstable slope with the attendant safety issues that would be thrown up if excavation works had to be undertaken on it.
109. The new sewer would be rerouted across fields to the north of Dene Lodge from MHA to the road and would run along the road past Dene Lodge and the houses on Elmfield Terrace running down the southernmost side of that terrace and then into the sewage treatment works. The plan called for a clay stank to be inserted at MHA at the point where the old sewer connected with that manhole. A clay stank is simply a piece of clay placed in position to block running water and/or effluent. It is basically a mini dam. Mr Patel’'s evidence was that a stank is inserted as a matter of precautionary common practice, it is cheap and easy to install and there is really no downside to putting one in.

Mr Mark Johnson

110. He is a project manager employed by the Defendant. He first became involved with this site in 2007 but was more intimately involved from 2010 when he became the Defendant’'s project manager responsible for the permanent diversion. It was he who sanctioned a revision in the plan relating to the section of abandoned pipe that was initially to be removed completely from the ground. He covers that in paragraph 10 of his witness statement. Essentially he was told by Entec, the technical contractors that the instability of the ground militated against digging down to retrieve old pipe and the decision was made simply to remove, by hand, any pipe actually at ground level.
111. He cannot say to what extent in 2010/11 he was precisely aware of extent the pipe was grouted as required by the adopted scheme but he saw the pipes downstream of manhole 5701 (which is itself just north of the Claimants’' property) in 2014 when he attended with Dr Jones. His evidence was that he saw grout in those pipes which were still in situ.

Mrs Beatrice Brindley

112. She is a project manager with the Defendant. Her role involves delivering capital projects for the Defendant. She managed the project up to the point where the contractor was appointed to undertake the work. At that point she handed over the reins to Mr Mark Johnson who actually managed the construction.
113. She commissioned a feasibility study from Entec in 2010. It is to be found at D1 AP3. At paragraph 6.1.3 of the report there is reference to a geotechnical desk study which had suggested that;

“"The failure of the existing combined sewer was likely to be due to progressive slope movement on the bank of Ogle Letch. It is considered most likely that original pipe failure was due to slope movement, however subsequent episodes of leaking sewage from broken pipes or open joints may have exacerbated the existing instability”"

114. In answer to Mr Collins she accepted that escapes of sewage could damage the subsoil.
115. She also gave evidence on the issue of the existence of a separate Elmfield Terrace sewer which I mentioned in paragraph 5 and 6 above. I deal with her evidence in this connection in paragraph 130 below

Mr Richard Woodhouse

116. His witness statement was unchallenged and he was not called. It does not address causation but rather the manner in which the Defendant prioritises its obligations and learns of problems in the network.

Mr Paul Scorer

117. His witness statement too is unchallenged and he was not called. I need say no more than it does not address issues pertinent to causation.

Mrs Sandra Hutton

118. She was a member of the call centre team contacted by Mrs Bell in 2001. She has not given evidence. Her computer record of that conversation is introduced by way of a hearsay statement.

The Experts

Dr George Reeves

119. As I mention in paragraph 16 above he is a chartered geologist and chartered environmentalist instructed by the Claimants. He has prepared 3 reports in this mater respectively dated 25 June 2013, 30 June 2014 and 15 July 2014. This last report is actually no more than a site activity log in respect of the visit to see the trial pits and photographs of that visit. Dr Reeves also produced a DVD of the site which was played to the court during the hearing.
120. He has an impressive CV which is set out at appendix A of his first report. He has experience in the investigation of groundwater flow and fluid transport in superficial deposits and bedrock and in Glacial Tills and their stability in the context of coastal regression and erosion.
121. For 18 years from 1986 he was a member of the academic staff in the Department of Geotechnical Engineering at the University of Newcastle and from 1989 was course director for the MSc course in Engineering Geology and latterly Geotechnical Engineering supervising a number of students on the topic of slope stability in superficial deposits with particular reference to glacial Tills, no doubt since that is the typical terrain in the North of England. He has published a number of papers on slope stability and groundwater flow.
122. He has worked as a consultant on various geotechnical projects including as a consultant for Entec and has appeared at a number of public enquiries as an expert witness but never as an expert witness in court proceedings. He is now the principal consultant at HydroGEOtech Consultants who specialise in Engineering Geology, Hydrogeology and Environmental Consultancy
123. It is as well to say at the outset that Mr Medd contends that he was a “"disastrous”" expert witness. He characterises him in paragraph 9 of his final submissions as being “"partial, combative and verbose”". From paragraph 12 of his final submissions Mr Medd seeks to demonstrate by examples what he describes as Dr Reeves egregious conduct. Mr Collins himself recognised in paragraph 17 of his submissions that Dr Reeves’' “"volubility and determination to make clear his position may well have had an impact on the ultimate clarity of his presentation”" but he argues that in the end his account was clear and consistent with the features present on the site.
124. I do not intend to address in any detail the observations made by Mr Medd from paragraph 12 of his final submissions save to say that I am surprised that there was no meeting of experts despite court orders that there should be and that that appears to have come about because Dr Reeves did not think that it was appropriate to have one when, in his view, he did not have a Part 35 compliant report from Dr Jones. It is not clear on what basis he felt that Dr Jones report was not Part 35 compliant. The attitude does betray a certain incalcitrance that is not a welcome trait in an expert. In my experience there is almost always something to be gained by a joint meeting of experts who approach the task with open minds.
125. In the end though the order for a joint meeting was revoked by HHJ Raeside QC. He clearly felt that there was a good reason why a joint meeting would serve no purpose and so it would be wrong in my view to treat Dr Reeves evidence as in some way less reliable because he initially refused a meeting. The fact is that it is of course vital to look past such matters, and the manner in which the evidence was given, and to focus on its content and cogency. In this connection Mr Collins reminds me that Dr Reeves has spent a very great deal of time at the site consisting of 3 days before he wrote his first report and another 2 days in anticipation of his second report and there have been visits to site on a number of occasions since.
126. In paragraph 9 above I have in effect summarised the purport of Dr Reeves’' conclusions as to why there is a continuing failure of the slope but it is important to add a little detail to that by reference to his first report. Briefly, by reference to his written reports, he forms his view because;

a. The slope angles of the bank of the burn below Dene Lodge are only about 15 to 20 degrees. Glacial till such as this is usually stable until the slope is about 28 degrees.

b. The slope is eroding from the top to the bottom. There is, he says, a down slope movement of material from the top of the slope which is in stark contrast to the small slope failure due to toe ^[9] erosion by the flow of water in the stream.

c. Evidence of rotational shears can be seen in the top of the slope because the shear strength of the clay has been weakened by continuous saturation of the upper part of the slope by fluids emanating from the pipe or its trench.

d. There is no other slope movement occurring at other parts of the bank at different locations that have a similar incline.

e. A chemical reaction between the clay and alkaline in effluent will also undermine the integrity of the slope

127. He is clear that the cause is the saturation of the slope comes from the pipe and the trench in which it sits rather than from any other source. He argues that if it were otherwise other areas with a similar incline would be failing -- and they are not.
128. He (and indeed the Particulars of Claim) speaks of the trench in which the pipe sat or continues to sit as being backfilled with sand and gravel providing a preferential pathway for sub surface flow of fluids right across the areas which are the source of the landslip. He refers to learned papers which describe this phenomenon of preferential pathways for fluid through trenches (Preene and Brassington 2003). It is right to remind myself at this point of what I have recorded in paragraph 17 above to the effect that there is limited evidence of sand and gravel backfill in these trenches but in the witness box Dr Reeves was still clear that the phenomenon was at work here, for the reasons that I set out in paragraph 17.
129. His second report deals with the trial pits (TP) and information gained therefrom. His conclusion is that the evidence from the trial pits supports his initial conclusions. The location of each trial pit is seen on the plan at E89A.
130. Before I come to those conclusions I record that it is in this report Dr Reeves contends that the pipe has moved significantly to the east i.e. down the slope from trial pit X shown on the plan at E89A. It now rests in the position marked by Trial Pits A to E on that plan. In places he puts the movement from its original position as over 7 metres. Mr Medd argues that that is plainly wrong and is based on a misconception that there is only one sewer pipe when in fact there are two. I touch upon this in paragraphs 5 and 115 above. The plan at AP6 to which I have already referred shows 2 sewers and Mrs Brindley in her witness statement explains that originally the Claimants’' private sewer connected with the sewer from Beacon Road but as part of the 2010 diversion scheme it was connected to the Elmfield Terrace sewer which was extended northwards for that purpose from manhole 5702 to MH X. As I have mentioned at paragraph 98 above, the CCTV plan attached to Mr Howliston’'s witness statement also shows two separate sewers.
131. In fact in one sense whether there is one sewer or two does not matter. If fluid is coming from either and is causing the slope to slip then the Claimants succeed. The significance asserted by Mr Medd is that the very fact that Dr Reeves can believe that there was only one sewer originally in the position actually occupied by the Elmfield Road sewer and that it has slipped down the hill by up to 7 metres undermines his credibility generally because it has resulted in him basing his opinions on an incorrect understanding of where the Pipe with which I am concerned lay at the material time.
132. I now turn to the conclusions in Dr Reeves’' second report and what was seen in the trial pits;

a. TPB reveals that the pipe is only incompletely grouted in that there is grout in only the bottom of the pipe.

b. Water emerged under pressure from the pipe in TPA into the excavated hole and seepage from the pipe joint was noted..^[10]

c. Seepage was noted from the pipe at TPC and TPD.

133. The conclusions drawn are that;

a. The abandoned sewer remains in the ground notwithstanding that the original plan shows that in the area to the east of Dene Lodge it should be removed.

b. There has been grouting which is ineffective in preventing lateral flow of fluid along the pipe.

c. Repairs to joints were ineffective in sealing leaks.

d. There is a trench providing a preferential pathway for subsurface fluids.

e. The defective pipe and the trench are introducing moisture into the area which is slipping and is the cause of the slippage because it has made the area too saturated to remain stable.

f. As regards Syd’'s Wood Garage, made ground and the outfall of water from the highway drain, these are all minor features in only one of the areas of landslip and make little, if any, contribution to the slope failure. Indeed it can be seen in the trial pits that the made ground is insignificant. ^[11]

134. It is appropriate to note that on page 12 of his report he refers once again to a backfill of granular disturbed material which is the medium that provides this preferential route for this subsurface fluid.
135. I now turn to Dr Reeves’' oral evidence in chief. He was asked why, if water utilises the preferential pathway created by a trench it simply does not continue on that pathway down the slope all the way to the area of the sewage treatment works. If it were to do so then clearly there would be less scope for a build up of water in the slope to the east of Dene Lodge and less risk therefore of saturation leading to instability. His response was that the shearing of the ground causing it to fall away has fractured the line of the trench thereby blocking the route of the water and causing it to build up in this area. He said that the shearing had in effect caused a natural clay stank that stopped the water in its tracks.
136. He was asked by Mr Collins to confirm that his view remained that any made ground on the slope of any structures abutting the slope such as Syd’'s Wood Garage will not be contributing to the slippage. He was clear that the made ground was not substantial enough to be a culprit and nor was the garage. He referred to a Google photo at E54 taken in July 2006. He pointed out that that photo showed other more substantial structures to the rear of the houses on Elmfield Terrace and essentially at the lip of the slope down to the burn yet, he said, there was no slippage in these areas. In fact in some places the slope down to the burn is more acute opposite Elmfield Terrace than it is opposite Dene Lodge.
137. It is right to record that he also referred to the Google photograph in support of his contention that the garden is slipping. He sought to argue that the photo of the area shows that the garden is not sloping. It is unclear to me how one can assess the angle of incline of ground from a photograph taken directly overhead.
138. In his examination in chief he was also referred to the clay stank that I refer to in paragraph 109. He argued that the very purpose of these is to prevent the lateral transfer of subsurface fluids along a linear route (i.e. a trench). He argued that the very fact that one was inserted demonstrates that the Defendant was aware of this phenomenon and that it was likely to occur here. Of course Mr Patel’'s evidence was that they are installed as a matter of course because they are cheap and easy to install and there is no disadvantage in doing so.
139. In cross examination, on the matter of the comparison between the slope at Dene Lodge and that further south, adjacent to the Elmfield Terrace houses, he admitted that he took no measurements to establish how saturated the more southerly slopes were but he did look at them “"with a field geologist’'s eye”". He accepted that the ground to the north of Dene Lodge was waterlogged at various times when he walked it.
140. On the issue of the slippage sustained by the Pipe, he acknowledged that a plan prepared by Mr Kenneth Johnson and which Dr Reeves had adopted for the purpose of his reports (E89A) was inconsistent with the plan at NH1 (the CCTV survey of 2007 referred to in paragraph 8 of Mr Howliston’'s witness statement) and that that latter report was likely to be the more accurate in respect of the original line of the sewer.
141. He did not accept that the line of the pipe revealed by the trial pits was the original line as shown on the CCTV survey plan. He thought that the pipe as revealed in the trial pits was further down the slope than is shown on the CCTV plan and so remained clear that the Pipe had slipped “"3 to 4 metres, maybe more since 2007”". He was clear that the pipe will have moved in sections and incrementally (by which I mean that the distance between its original position and where it is shown in the trial pits increases the further downstream one goes). For the reasons I mention in paragraph 135 above, this will have the effect of impeding the continued flow of water away from this saturated area.
142. Manhole 5701 is in an area downstream or south of where the Pipe was abandoned in favour of the diversion scheme. It is also downstream of the clay stank inserted close to the point where the diversion takes effect. Dr Reeves said that he opened that manhole and it was full of water. That in itself, he argues, is important when the pipe connected to it is now out of commission and supports the view that water is still travelling down the pipe.
143. That manhole is upstream (or north) of the bank adjacent to Dene Lodge and so in itself does not necessarily show that water is travelling from that manhole further to the south but, says Dr Reeves, on occasions that manhole has been found to be dry which suggests to him that water is leaving it to carry on downhill either through the abandoned pipe or the trench in which the pipe sits.
144. Dr Reeves was unable to say how much fluid the pipe carried before its abandonment or indeed what volume was leaking out of it since.
145. Mr Medd raised with him the question of the grouting. He remained critical of it. He felt that it was not performing its function of stopping water flow and his evidence for that was that the trial pits contained water to a greater or lesser extent that had come from the pipe. He was prepared to accept that the trial pits contained water that had emanated from the pipe on the basis of what Mr Bell had told him he had seen when he dug the pits. He was prepared to concede that, were it not for the observations of Mr Bell that water had seeped from the pipe when he dug the pits, it could have been equally possible that water in the pits had come from another source.
146. He was taken to Building Regulations applicable to sewer construction and decommissioning. He mentioned these in his second report. It was a criticism of his that the work done in the course of decommissioning the pipe did not comply with the Regulations. In fact it was not accepted that the Regulations apply to a statutory undertaker such as the Defendant but in any event by reference to paragraph 9 of his second report it appears that by Regulation B18 grouting is necessary simply to ensure that rats cannot colonise the pipe.
147. He was asked about the drainage channel constructed by Mr Bell. He was taken to a letter that he wrote to the court on 25 November 2015 (A2 428). In it he mistakenly refers to it as highway drainage but it is clear he is referring to the drainage channel. He said that it contributes to the saturation of the failing slope.
148. As for the drainage from the highway drain that captures water on the road from the Beacon Terrace area and drains it into the beck in the vicinity of the burn, he said that he was not clear where the outfall was but felt that it was close to the water. He referred to dye being placed into the drain and appearing in the burn with no significant green trail leading down to the burn suggesting that the outfall is near the water and much lower than the areas of slippage. However, it was clear from the exchanges with counsel that then took place that Dr Reeves could not really say at what height in the slope water emerged from the highway drainage pipe. I remind myself that Mr Bell thinks that the outfall is 4 to 5 metres above the burn (see paragraph 74).
149. I turn to the question of sand and gravel and the suggestion that this forms a permeable membrane surrounding the pipe through which water can easily travel and saturate the area adjacent to Dene Lodge. It cannot be denied that it was the consistent evidence of Dr Reeves in his reports and it translated into the Particulars of Claim that this pipe was laid in sand and gravel. Mr Medd suggests that there has been an important shift from that position to one where the contention is that the permeable membrane is no more than disaggregated or disturbed clay.
150. It is a point I make in paragraph 17 above and I confess that I formed the same view as Mr Medd that there had been a shift from the written position but not in my view a complete abandonment of it. At a late stage in the hearing photographs were produced and Dr Reeves suggested that one of them (photograph E) does show a granular material in the trial pits. Others however from other trial pits do not so far as I can see and the pipe at trial pit E appears to have been repaired at some time in the relatively recent past before the pipe was abandoned.
151. Finally I remind myself of an exchange between Mr Medd and Dr Reeves towards the end of his evidence after, it has to be said, a lengthy and trying time in the box. He said;

“" I can’'t say whether this slippage would have occurred even if the pipe had not been there and was never there. I don’'t think anybody can but the rest of Ogle Letch has not failed and the only difference is this pipe. There must be highway drainage in place in other areas but there has been no problem there”"

152. Mr Medd suggests that this is a concession that is fatal to the Claimants’' case. It has to be said that in answer to me he seemed to row back from that substantially. He was clear that the instability would not have occurred but for the pipe. Instability leading to slippage has not occurred elsewhere in areas steeper than this.

Dr David Barrie Jones

153. He is a consulting civil engineer and geotechnical specialist now running a dispute resolution and expert witness business. Like Dr Reeves, he has an impressive CV to be found at page E168.
154. He has his doctorate in Soil Mechanics and Numerical Methods and while he has not been involved in academia to the same extent as Dr Reeves, in 1996 he was an external PhD examiner and he is a specialist in earthwork design, site investigation, slope stabilisation and landslide management. He is the author of many papers on these and other topics.
155. He has much practical experience in the matter of consideration of landslip in particular the stability of slag heaps following the tragedy at Aberfan. His evidence was that the existence of pipes even in slag heaps is not an usual phenomenon and their effect on the stability of the slag heap is something that he has been called upon to assess in the course of his career.
156. He has visited the site on two occasions and it is right to record that on each occasion he was accompanied by representatives of the Defendant who were able to ensure that he had access to the site and explain the history of their involvement with it.
157. He noted 2 areas of ground movement, one to the north in the area in which the telegraph pole is situated and one in the area below Syd’'s Wood Garage. There is disturbed land between those areas.
158. His report dated September 2015 is at E121 with his conclusions at E163. He does not dispute that the evidence shows that the pipe was in poor condition and there will have been leaks from the sewer but they will have been negligible, insignificant and indeed he suggested “"miniscule”" when compared to water absorbed into this slope from other sources. He pointed out that albeit this was a combined sewer it would only be used intermittently when people in the Beacon Road area use their facilities or there is rainfall but even then much of that will be caught by watercourses. His view was that the sewer pipe has not contributed to the landslip at all. Any movement of the pipe has been caused by slippage of the land, not the other way around.
159. He does not accept that there will be any fluid passing through a preferential path of permeable material. He does not dispute that trenches can create a preferential pathway for fluids as per Preene and Brassington but he does not accept that there is any sand and gravel in this trench or that the disaggregated clay disturbed when the pipe was laid will be a conduit for sub surface fluids in this case.
160. His view with regard to that (based upon his experience of seeing in situ other pipes that were laid in the 1920s) is that they tend to be packed with the surrounding material (here Glacial Till) and that its constructors would have compacted the clay as they went by moulding it, like dough, around the pipe and trampling it in after having buried the pipe. Furthermore over the next 80 years or so the clay would settle and compact even more and consolidate around the pipe. He argues that packing the clay around the pipes would have been a necessary precaution, not least to ensure that there were no void areas under the pipe because a pipe traversing a space is more likely to break at that point.
161. His view is that in fact the clay around the pipes will be less permeable than the undisturbed clay because natural ground is composed in horizontal layers and permeability is greater in the horizontal plane than the vertical. When material is excavated and then trampled back into a trench such as occurred here the natural horizontal seepage points are destroyed. That effect will be enhanced over time as the material settles and consolidates further. In any event the principle of the preferential pathway is based on the premise that water will find the easiest route downhill. Plate 12 at E192 would suggest that in places in fact that might be horizontally to the surface and then down the slope to the burn as surface water.
162. He accounts for the slippage on the basis set out in paragraph 5.1.9;

a. The bank in its natural state is probably only marginally stable but the bank to the east of Dene Lodge has had significant made ground tipped onto it and at the lip of the slope. In paragraph 5.1.2 of his report he specifically singles out the made ground adjacent to Syd’'s Wood Garage because not only is its weight a factor but it serves to block or partially block the highway drain. However he points out that there is also made ground further to the north, on an area of landslip.

b. Ground movement has clearly occurred before 2007. This is clear because the foundations of the telegraph pole to the north of Dene Lodge (and well away from the area of land slip near Syd’'s Wood Garage) were affected by saturation even before 2001. I refer to this in paragraph 76 above.

c. The drainage channel to the north of the property is draining into an area affected by land slip. If, as is common ground, the landslip is caused by saturation then it is argued that that channel (both before and after it was enlarged in 2014) has been introducing into an already naturally wet area copious volumes of water from the pavement of Beacon Road and the hills below the pavement but above Dene Lodge.

d. The highway drain flows onto the bank adjacent to the property adding to saturation caused by a high water table. Not only that but, as I have said, the outfall is obscured by made ground.

e. Surface water from the rear of Dene Lodge is running onto the slope from areas other than the drainage channel because Dene Lodge is higher up than the slope and slopes towards it.

f. Erosion caused by the fact that this area is on the outside of a bend in the burn. ^[12].

g. Rainfall and a natural rise in the water table.

163. He was referred to a plan at C KJ4 which shows the defects in the pipe in 2010. As I have said, he did not dispute that there were defects all the way along the pipe but not all defects result in leakage and some, for example at a collar, may well not affect the integrity of the pipe at all. If, as here, there are generally only relatively small amounts of water in the pipe any defect at the top of the pipe is also unlikely to result in a leak. Equally, a displaced joint may simply mean it is out of true but that does not necessarily mean that it leaks, there is some flexibility in the pipes, even earthenware ones such as these.
164. He was clear that in his view, prior to the diversion scheme in 2010, with the exception of the point in September 2007 when there was no flow to the sewage works and the temporary repair was undertaken, the overwhelming majority of the contents of the sewer was reaching the sewage works. He pointed out that even when a sewer collapse was reported by Mrs Deeble dye inserted upstream of the collapse emerged in the pipe downstream of it. I refer to this in paragraph 101 above.
165. As regards the height of the water table, on plan C KJ4 one particular joint in the pipe to the north of Dene Lodge has been labelled as “"joint displaced, heavy infiltration”", another slightly to the south of that as “"Joint Displaced infiltration”". He remarked that if water was entering the pipe it meant that the water table is higher than the pipe. It supports his view that this whole area is waterlogged.
166. He derives evidence from plate 27 on E207 as to the height of the water table. This is a photograph of TPC which is in an area of the slope abutting the extension to Dene Lodge. It shows water in the pit that has seeped into it from the clay wall from a point higher than the pipe. Dr Jones can see that from the discolouration of the clay wall. The same is true by reference to plate 28 on E208. This shows a water line on the clay wall of pit TPC which is above the pipe and so cannot be as a result of seepage from the pipe or the trench. He points out that these plates were taken in July 2014. Usually in summer the water table is lower than it is in winter. He remarked that this is a very wet area in any event with significant groundwater affecting the entire area.
167. As regards his evidence of the effect of made ground, he drew attention for example to plate 25 at E206. It is a picture of TPB in an area of the slope abutting the extension to Dene Lodge. It shows a great deal of made ground sitting atop the original terrain. The same is shown on plate 26 on E207 in respect of TPC which is in the same area. That too shows a significant quantity of made ground which appears to have been dumped over the pipe.
168. Where does this made ground come from? In Dr Jones’'s view it is the earth excavated during construction of Dene Lodge and/or the extension to it. He recalled that the bungalow had to be benched into the slope and benching produces arisings that have to be put somewhere. He referred to a number of photographs in his report which show areas of made ground visible just from a perusal of the site and without reference to trial pits. His view was that around Syd’'s Wood Garage there was between 20 to 30 tonnes of made ground. He pointed out that that amounts only to one lorry load of earth and that 1 cubic metre of this clay weighs about 2 tonnes.
169. In particular he noticed some heaved ground just east of Syd’'s Wood Garage. He shows this on a plan at E220. On that plan an area coloured orange represents material laid on the slope to support the garage and the heave is as a result of pressure on the ground caused by weight which causes the ground to rise.
170. He had some observations about the highway drain. He was unclear about where it discharged but it was clearly in the slope and not the burn itself. In any event water is hitting this slope at this point not only from that drain but it runs off the access road under which that drain runs and from Dene Lodge itself. He referred to plate 2 on E190. There is an incised watercourse shown on E196 which if not caused by the water flowing from the drain is caused by water hitting the slope from these other sources.
171. Mr Collins asked him about the highway drain. He took Dr Jones to a letter from the Local Authority of 31 October 1980 which speaks of the highway water originally draining by means of a stone culvert which took water to the burn and which was later replaced by a pipe in a concrete surround. The point is however that he was unclear where the outfall for that pipe was but was clear that significant volumes of water will come down that pipe and discharge onto the slope at some point during, and immediately following, rainfall.
172. I should say a word about Dr Jones reaction to the contention by Dr Reeves that this pipe has slipped some metres down the slope. It will be remembered that initially he thought by as much as 7.3 metres but in his oral evidence he moderated that to up to 4 to 5 metres. Dr Jones does not agree that that is what had occurred. Leaving aside the issue as to the existence of the Elmfield Terrace sewer which Dr Jones argues clearly exists, I was referred to a photograph at E223 taken in March 2015 and upon which Dr Jones superimposed a line showing Dr Reeves original line of the sewer and a broken line showing the displaced sewer as suggested by Dr Reeves. Dr Jones argued that if there had been such a serious movement one would expect to see evidence of movement at the surface at all points where slippage of the pipe has occurred but one does not see that.
173. He was clear that the clay stank would simply have been installed automatically, as a precaution whether it was needed or not. It did not signify the Defendant expected water to continue through an abandoned pipe or trench system and sought to take unusual steps to prevent that.
174. He was equally clear that he could see no granular material such as sand or gravel in the trial pits when he saw them save perhaps in photograph E to which Mr Collins took him but he felt that that photograph itself demonstrated that there was no permeable material towards the bottom of the pipe. The water in the pit was standing water and was not ebbing away. He agreed that there was evidence of coarse material resting on the pipe but this was on a section of the pipe that had been repaired.
175. I have mentioned that Dr Reeves felt that the structural integrity of the clay will also be compromised by the manner in which the clay reacts with raw sewage. Dr Jones did not agree with this as a general proposition. Whether it does or not depends on the nature of the clay. He felt that this glacial till was not prone to chemical breakdown; it derived its strength and stability for cohesion and friction. The areas of slippage are extremely wet, not least because of the high water table. This affects cohesion. He suggested that this area is only marginally stable even at 18 to 20 degrees because of the amount of water in the ground from sources other than the pipe and trench.
176. He pointed out that the land is very hummocky in any event which in itself complicates the assessment of the level of incline as well as being an indicator of ground movement.

Conclusion as to causation

177. I should first make clear that I have concluded that Mr Bell’'s evidence as to the volume of material excavated during the initial construction of Dene Lodge and the extension was not reliable. I do not suggest that he has deliberately sought to mislead. It is equally possible that wishful thinking has inadvertently affected his recollection. The fact however that in part his evidence cannot be relied upon does inevitably have a knock on effect in other areas. I touch on this in paragraph 180 below.
178. It is clear that the benching into the slope necessary for the level construction of the bungalow and the extension was extensive and that it would create substantial arisings. I remind myself of the evidence of Mr Kenneth Johnson that the difference in height between the front garden and the back is about 2.5 metres and the scenario portrayed by the photographs to which I have referred at paragraph 69 above. It is equally clear to me that a significant quantity of the material excavated by the benching will then have been deposited in the back garden and on the slope to the burn because that was an obvious place to put it. The presence of up to 0.5 metres of made ground in trial pits (to which I refer in paragraph 70 above) also adds cogency to that view. I remind myself of Dr Jones’'s evidence that 1 cubic metre of this clay can weigh up to 2 tonnes.
179. It is equally clear that the bank of the burn immediately to the east of the boundary of Dene Lodge and in the vicinity of Syd’'s Wood Garage has been used as a dumping ground. I refer for example to the observations I made in this regard in paragraphs 72 and 73 above.
180. I mention in paragraph 78 above Mr Bell’'s remark that when he dug trial pit A water “"cascaded”" out of the pipe. Dr Reeves saw this as significant. Indeed, as I point out in paragraph 145 above, the conclusion he reached as to the reason that there was water in the trial pits was based upon what Mr Bell told him he had seen when he (Mr Bell) had dug the trial pits. If Mr Bell’'s evidence cannot be wholly relied upon then to the extent that any conclusions of Dr Jones/Reeves? are reliant on them then that inevitably affects their validity.
181. I should also make it clear that I do not overlook that the evidence of some of the Defendant’'s own witnesses appears to be that at the relevant time the sewerage pipe was at least contributing to landslip. I have in mind here the notes of Mrs Deeble that I refer to in paragraph 91 and I accept that it may well be that her observations recorded at paragraph 102 suggest that even in 2010 she may have had a suspicion that there was a sinister connection between landslip and the state of the pipe. However, I accept that the focus of her concern was not what the cause of the landslip was but the effect of it. I repeat what is said in paragraph 100 above. In any event, other analyses commissioned by the Defendant at the time concluded that any pipe failure was the result of landslip, not the cause of it (see paragraphs 107 and 113 above).
182. In reality however the crucial evidence on causation is that of the experts. Dr Reeves argues that the instability of the bank of the burn immediately to the east of Dene Lodge is caused or materially contributed to by fluid that has run and is running through the Defendant’'s sewer pipe (or what remains of it) and/or the trench in which the sewer pipe was originally laid. If I accept that evidence then the Claimants have discharged the burden on them of establishing causation.
183. If, on the other hand, I prefer the evidence of Dr Jones that the instability is caused by factors to which the pipe and/or the pipe trench have made no, or no material, contribution then the Claimants fail.
184. As the parties are entitled to expect, I have considered the evidence of the experts very carefully and, while Dr Reeves is clearly accomplished in his field, I have concluded that the evidence of Dr Jones is the more persuasive notwithstanding that he appears to have spent less time on site than Dr Reeves.
185. There are inevitably a number of reasons why I have taken that view based on the contents of the evidence given by both rather than in the way that the evidence was given albeit that it should be said that I did feel that the manner in which Dr Jones gave his evidence was the more measured and was considerably less prolix.
186. I turn to the question of whether there is one sewer at this location or two. As I have mentioned in paragraph 131 above, in a real sense that does not matter but it cannot be gainsaid that if there are two then that does have a material affect on the credence that can be attached to Dr Reeves conclusions generally. On the other hand, confidence in Dr Jones’'s conclusion would be adversely affected if in fact he is wrong and there was only one sewer that has moved down the slope (by up to 7 metres on the basis of Dr Reeves written evidence albeit by somewhat less on the basis of his oral evidence).
187. I am satisfied that there were 2 sewers, the Pipe and the Elmfield Terrace Sewer to which I refer in paragraph 5 above. That is the state of affairs demonstrated for example on the plans at AP6 and NH1 and it was the evidence of Mrs Brindley to which I refer in paragraph 130 above. Dr Jones’'s view, summarised in paragraph 172 above, was also cogent evidence that Dr Reeves was labouring under a misconception. Indeed, as I understand Dr Reeves’'s evidence he himself in cross examination conceded that may be the case because he accepted that the plan at NH1 (which shows 2 sewers) is more likely to be accurate than that prepared by Mr Kenneth Johnson at E89A which shows only one and was the plan which Dr Reeves had adopted for the purpose of his reports. In this connection I refer to paragraph 140 above. As I have said, this finding must shake confidence in Dr Reeves’'s approach and conclusions.
188. Another cause of concern is the apparent shift in his view of the material surrounding the pipe to which I refer in paragraphs 149 and 150 above. I recognise that he did not formally abandon the idea that the pipe had been backfilled with sand and gravel but that was certainly not how he approached the issue of the permeable drainage pathway when he gave his evidence in chief from the witness box. That evidence gave the clear impression that the permeable pathway was formed by disaggregated clay alone. If there was a shift then that is not encouraging as a basis for acceptance of Dr Reeves’'s theory as to the damage to the slope caused, or materially contributed to, by fluid permeating along the trench.
189. If in fact Dr Reeves has not departed from his position that this trench was backfilled with sand and gravel then I am not satisfied that it was. It has to be said that the evidence of Dr Jones on this issue (which I record at paragraph 160) made sense and it must also be said that no foreign permeable material was found in any trial pit other than possibly in TPE but in that case it is by no means clear that that had not been backfill introduced simply at that location following a repair. I refer to this in paragraph 150.
190. I appreciate that the absence of an obviously permeable medium like sand and gravel is not of itself destructive of the theory that fluid has been introduced into the slope via a permeable pathway made up simply of clay. Dr Jones however is clear that that will not have occurred here. I refer back to paragraph 161 for his reasons. It is also right to note that compaction of the clay will be accelerated if additional weight is applied over it, as would be the case if made ground is introduced to the area -- as I find that it was, certainly in the area of the trial pits. His reasoning commends itself to me. It is difficult to see how, 80 years or so after construction, and with made ground adding weight over the pipe clay which may originally have been permeable because it had been disturbed, would remain permeable to the extent suggested by Dr Reeves.
191. Even if however Dr Jones is wrong and the clay still provides a permeable pathway then I return to the question posed at paragraph 135 above namely why does this permeable pathway cease to be permeable at the point adjacent to Dene Lodge so that the water is stopped in its tracks there and saturates that area? Why does it not continue downwards on this pathway past the relevant bank and onwards to the sewage works? The answer says Dr Reeves is summarised in paragraph 135 namely that when the bank has sheared the line of the trench is fractured and a natural stank is created that prevents the water from continuing its downward progress.
192. The problem with this response is that even on the basis of Dr Reeves’'s evidence there are landslips caused by shearing in the area to the north of the property (near the telegraph pole and the drainage channel) and to the east of the property, downstream, in the area of Syd’'s Wood Garage. If a shear causes a natural stank preventing progress through the permeable medium then I ask rhetorically how fluids would travel in the trench from the upstream landslip to the downstream one? It is not likely they would be dammed by the upstream shear?
193. While dealing with clay stanks, I remind myself that Dr Reeves believed that the fact that a clay stank was deliberately installed at MH A (see paragraph 109) demonstrates that the Defendant was concerned about the effect of fluids running along the permeable pathway. I accept the evidence of Mr Patel and indeed Dr Jones that these are installed as a matter of course because it is cheap and quick to do so. However perhaps even more fundamentally, it is in my view likely that such a stank would stop any flow of water at or near MH A ie well upstream of Dene Lodge. That is, after all, its function.
194. It is an important part of the Claimants’' case that in fact fluid is still running through the trench from well upstream of MH A. Dr Reeves has not suggested that the clay stank installed by the Defendant is defective. If it is not defective then any permeable pathway is effectively interrupted well to the north (and upstream) of the areas of landslip that affect Dene Lodge.
195. I note that Dr Reeves pointed out that Manhole 5701 downstream of the stank was seen to be full of water. He argues that this is indicative of water passing through the pipe (or trench) into the manhole downstream of the stank installed by the Defendant but Dr Jones associated this with the general level of saturation of the area and the height of the water table which would cause water to seep into the manhole from the area surrounding it.
196. I accept that evidence because in my judgment there is clear evidence that the water table is high in this area. I refer to paragraphs 165 and 166 above as my basis for so finding - added to the fact that, as I have said, there is nothing to suggest that the clay stank installed by the Defendant at MH A is defective. In addition there is Dr Reeves’'s own evidence, recorded at paragraph 139, that when he walked the area north of Dene Lodge it was often waterlogged.
197. Let me deal with grouting. It will be recalled that Dr Reeves argues that it is defective and incomplete and thus ineffective in preventing lateral flow of fluid. First, I remind myself that he criticised the grouting on the basis that it failed to comply with Building Regulations but it was not accepted that those are applicable to a statutory undertaker such as the Defendant. Secondly, even if they do apply, the purpose of grouting seems to centre more on depriving rats of a nest in the pipes than anything else ^[13] although I accept of course that a pipe which has been completely filled with grout is going to be less permeable and more able to withstand collapse than one that is not. Furthermore, the grouting was undertaken by independent contractors. I make observations about that from paragraph 208 below.
198. Perhaps most fundamentally, it is quite clear that copious quantities of water are being artificially introduced into the bank contiguous with the areas of landslip. Leaving aside the fact that Dene Lodge is situated on the line that rainwater falling higher up will take to reach the burn, there is the drainage channel excavated by Mr Bell. As I point out at paragraph 75 it was specifically built by him in 1995 to prevent the flooding of his garden by water coming down from the area of the Beacon terraced houses and the pavement, bearing in mind that the natural flow of such water would take it to the burn via Dene Lodge. The fact that his garden flooded and this engineering exercise had to be undertaken is an indication of the volumes of water involved. Indeed in 2014 he widened this channel using an excavator to do so. I have already remarked at paragraph 77 that it is quite an impressive feat of engineering. Where does all the water collected by this channel discharge? The answer is right into one of the areas prone to landslip – and at the top of the slope rather than the bottom and thus in the area where shearing has been identified.
199. The same is true of the other area of serious landslip namely in the area near Syd’'s Wood Garage. Here there is another outflow of water from the highway drainage pipe and rainwater running down the access road towards the burn. I am satisfied that the outflow to this pipe does not discharge water directly into the burn but rather onto the bank which will inevitably cause that part of the bank to become saturated affecting its qualities of cohesion. If Mr Bell is to be believed, and he is the person most intimately connected with the bank, the pipe discharges about 4 to 5 metres from the letch, allowing the water significant opportunity to be absorbed into the bank before it reaches the letch.
200. Dr Reeves argues that other slopes abutting the burn at the same or a more acute angle have not slipped. That may be so but I had no evidence that that was so notwithstanding that those areas had water directed onto them in the same volume as this slope does and that the only difference between those slopes and this was the existence of the Defendant’'s pipe and trench.
201. This brings me to the observations of Dr Reeves to which I refer in paragraph 151 above and to which Mr Medd attaches great emphasis in his final submissions. It has to be said, they were telling. Even in so far as it goes, it lacks some cogency because, even if there is a highway drainage pipe in other areas of this slope (and no evidence was adduced to that effect), then that ignores in any event the effect that the drainage channel created by Mr Bell has had in the area about which I am concerned and the fact that this area consists of made ground as well as natural ground.

Material Contribution

202. In his final submissions Mr Collins raises the issue of material contribution on the basis that even if the defective pipe and/or trench is not the sole cause of the instability in the land then it materially contributed to it and that is enough for liability to be established.
203. Mr Medd has suggested that the “"material contribution test”" is in any event the wrong test to apply in the search for causation. His position is that in so far as it is open to the Claimant to put forward a case on a basis other than that the presence of the defective pipe and the trench was the sole cause of the instability of the land then the Claimant can only succeed if it can establish that “"but for”" the presence of the defective pipe and the trench and fluid transported to the site by the pipe or trench the land would not be unstable.
204. Mr Medd has referred me to the recent case of Chetwynd v Tunmore 2016 EWHC 156 (QB) where HH Judge Reddihough sitting as a Judge of the High Court had to consider whether the excavation of 4 lakes by the Defendants on their land had caused a significant decrease in the water levels in the ponds on the Claimant’'s land. He carefully analysed both tests and concluded that the approach in disease and clinical negligence cases of only having to establish a material contribution to the injury could not properly be extended to a case such as the one with which he was concerned. He remarked at paragraph 34 that;

“"the essence of the Claimants’' case is that a reduction of the water levels in the ponds causes their alleged loss and damage. Thus, in my judgment, the Claimants must prove on the balance of probabilities that, but for the excavation of the lakes, their loss and damage would not have occurred.

205. This case has much in common with Chetwynd and it would be difficult to draw any distinctions that would justify a different approach to that adopted by the learned judge in that case. However, and cognisant of the fact that Mr Collins has not had the opportunity to address the principles raised in that case, I have to say that, even if material contribution is the test, I am not satisfied that the presence of the defective pipe and fluid flowing through it or in the trench has materially contributed to the instability of the slope. I refer to the observations of Dr Jones that I record at paragraph 158 above. I agree that the effect is likely to be miniscule compared to the volumes of fluid hitting this slope from other sources.
206. I recognise that this pipe has been in poor condition for many years, nevertheless (except for the incident of no flow in 2007 which was quickly attended to) most of the fluid within has clearly reached its destination of the sewage works. I refer to Dr Jones’'s unchallenged evidence recorded at paragraphs 163 and 164 in respect of that. In so far as Mr Bell has seen effluent in or near the burn or Mr Kenneth Johnson noticed what he thought was the smell of sewage in 2011 that does not affect the contention that most reaches its destination of the sewage works and when the existence of effluent has been reported it has been dealt with quickly. In any event, in so far as the condition of the pipe is the result of ground movement rather than the cause of it then it does not help the Claimants as regards liability.^[14].
207. Furthermore it is not clear how much effluent or fluids this pipe carries. Effluent will only be carried when the residents of the Beacon houses use their facilities and other water will only be carried when it is wet. There are I think only 20 houses on Beacon Hill served by the Pipe.
208. In any event if, as I accept, the trench does not create a permeable pathway in the circumstances applicable here, then any effluent leaking will follow the line of easiest permeability. It was Dr Jones’'s unchallenged evidence that this may well be horizontal causing effluent to leak out onto the surface of the slope and then descend into the burn rather than take a route delineated by the pipe or its trench. I refer to paragraph 161.
209. I am not satisfied that sewage itself because of its alkaline nature will have materially contributed to the undermining of the integrity of this slope. I was not directed to any supporting evidence that that is what happens when sewage is in contact with clay of this kind. It was a proposition with which Dr Jones did not agree vis a vis this particular clay. In any event, the degree of water in the ground may well have the effect of diluting the effect of any alkaline in this clay.
210. If the “"but for”" test is applied, as in my judgment it should, for the reasons so clearly set out in Chetwynd, then the Claimant is in even greater difficulty. For the reasons I have set out above I cannot be satisfied that but for the presence of this fluid in the defective pipe and/or trench the instability in the slope would not have occurred. Of course I recognise that that was the final evidence of Dr Reeves, as I record at paragraph 152, but that has to be set against all the other evidence and not least his response to Mr Medd to which I refer in paragraph 151 and the fact that in fact there is no evidence that other areas of the bank abutting the letch bore made ground or were actually exposed to the same sort of volumes of rainwater as the area immediately adjacent to Dene Lodge.
211. In all the circumstances I am not satisfied that the Claimant have established causation and on that basis the claim must fail.

Fault based nuisance

212. It becomes unnecessary to dwell on the issue of whether the Claimant can establish that the Defendant was at fault since of course that issue is academic as a result of my finding that causation is not established.
213. It has to be said however that had this fallen for consideration I would have been minded to conclude that the Defendant is not at fault.
214. In so far as they adopted a reactive policy of identifying faults, their policy is no different to that adopted by Thames Utilities in Nicholson to which I refer in paragraph 27. As in that case, that policy is not open to question by this court.
215. As for their reaction when matters were reported to them, they instructed competent contractors to report and remedy. I have already found that the Defendant cannot avoid liability merely because they used independent contractors but in a situation such as this where if causation had been established, liability in nuisance would have been established only if there were fault on the part of the Defendant it is difficult to see what more it could properly do over and above what it actually did. It reacted timeously to complaints and it instructed contractors on its panel whose performance was regularly monitored and in whom it was reasonable to repose confidence and whom it was thus reasonable to instruct.
216. Any deviation from plans of action for example in not removing some of the pipe in the area where the plan was to remove it was carefully considered and there were reasonable explanations as to why the plan was departed from (relating to the instability of the ground and the safety risks involved in excavating pipes from that ground).
217. As far any delay in undertaking the project to divert the sewer, in my judgment this is more a strategic than operational in the sense adopted by Ramsey J in Dobson. I deal with this in paragraph 39 above.

Final Remarks

218. Let me say that I have a great deal of sympathy with the Claimants and my conclusions have not been reached lightly. The instability of this slope will inevitably and understandably be a source of enormous anxiety to them. I realise that my conclusions will be a considerable disappointment to them. While it will be no consolation to them I very much hope that a solution can be found for the problem that confronts them which does not involve significant cost to them and that will enable them to enjoy many future years in Dene Lodge.
219. I am grateful to counsel for their very able assistance in this matter. As I said in court at the conclusion of the hearing however I wish to express on record a sentiment with which Mr Medd graciously agreed. That is to express my particular thanks to Mr Collins who has dealt with this matter on a pro bono basis.
220. Cases are very much like icebergs in that a great deal of the time spent by counsel is invisible to the party that instructs them. The commitment in time that Mr Collins has clearly put into this complicated case, reflected in the skill with which he presented it, is patently enormous. To have done so on a pro bono basis should and does attract much gratitude from the court as well as no doubt from Mr and Mrs Bell.

HH Judge Saffman

Note 1   See witness statement of Beatrice Brindley paragraph 12    [Back]

Note 2   It is described by Dr Reeves, the Claimants’ expert as a “higher permeability drainage pathway”    [Back]

Note 3   Clerk and Lindsell Ed 21 para 20-142    [Back]

Note 4   It is not disputed that there has been leakage from the pipe because of defects in it    [Back]

Note 5   I do not overlook that there is another water course commencing at a junction in the road leading to the Beacon Road row of houses that will capture some of the water falling in that area and prevent it flowing onto the Claimants’ land or the slope to the burn abutting it    [Back]

Note 6   The evidence of Mr Woodhouse (which was not challenged) was, at paragraph 20 of his Witness Statement, that a grade 5 defect is “where the pipe moves, deforms, or collapses.” OR Category 5 defect means that sections of the sewer have collapsed.    [Back]

Note 7   Which had been installed as a temporary measure some years before    [Back]

Note 8   It should be noted that since 2007 this section of the pipe was not operative in any event and sewage was transported via 150 metres of plastic pipe installed in 2007 as part of the temporary repairs.    [Back]

Note 9   That part of the slope contiguous to the running water    [Back]

Note 10   In fact Dr Reeves did not see water emerge under pressure. He was simply told that by Mr Bell who had dug the pit.    [Back]

Note 11   I should add that at E10 he says that no builders’ rubble etc is evident below Dene Lodge. As Dr Reeves accepted, from the evidence of photographs attached to Dr Jones report, there is made ground here but insufficient to be a factor contributing to land slip.     [Back]

Note 12   Demonstrated by the plan at E219    [Back]

Note 13   See paragraph 146 above    [Back]

Note 14   Although I accept Mr Collins contention in paragraph 21 of his final submissions that there are defects along the whole length of the sewer, not just in the area abutting Dene Lodge    [Back]