England and Wales Court of Appeal (Civil Division) Decisions

IN THE COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM THE UPPER TRIBUNAL (LANDS CHAMBER)
HIS HONOUR JUDGE BRIDGE AND MR PETER McCREA F.R.I.C.S.
[2016] UKUT 300 (LC)

		Royal Courts of Justice Strand, London, WC2A 2LL
		8 September 2017

Lord Justice Lindblom:

Introduction

1. Did the Upper Tribunal (Lands Chamber) err in its approach to an award of compensation for loss incurred as a consequence of consent being refused for the felling of a tree protected by a Tree Preservation Order, whose roots were causing damage to a conservatory attached to a dwelling-house nearby? That is the question at the heart of this appeal.
2. The appellant, South Gloucestershire Council, is the compensating authority. The respondents are the claimants for compensation, Mr and Mrs Burge. Their claim for compensation was made under section 203 of the Town and Country Planning Act 1990 and article 9 of the South Gloucestershire District Council (Land to the rear of 25 Saxon Way) Tree Preservation Order 2007 (SGTPO 15/07) ("the TPO").
3. In May 2003 Mr and Mrs Burge had erected a conservatory to the rear of their house at 27 Saxon Way, Bradley Stoke in Gloucestershire. In mid-2006 cracking began to appear both to the house and to the conservatory. In September 2007 Mr and Mrs Burge were advised that the damage to the conservatory was being caused by an oak tree on adjacent land. The oak tree, it is agreed, had been planted sometime before 1946. The council made the TPO, protecting the oak tree, in December 2007 and confirmed it in June 2008. On 2 September 2008, Mr and Mrs Burge made an application to the council for consent to fell the tree. That application was refused on 3 October 2008. A further application was made on 1 April 2010. That too was refused, on 28 May 2010. On 5 July 2010 Mr and Mrs Burge made an application for compensation under article 9(1) of the TPO. The claim for compensation, resisted by the council, was referred to the Tribunal on 8 October 2015. In its decision dated 27 July 2016, after a hearing on 23 June 2016, the Tribunal awarded Mr and Mrs Burge the sum of £25,000 in compensation. That sum had been agreed between the parties as the figure for compensation if the claim were to succeed. The council appealed against the Tribunal's decision on 24 August 2016. Permission to appeal was refused by the Tribunal on 12 October 2016, but granted by Lewison L.J. on 8 February 2017.

The issues in the appeal

4. There were originally three grounds of appeal. Lewison L.J. granted permission to appeal on two of those grounds, namely:

"The order of the Upper Tribunal (Lands Chamber) to award compensation to the Claimants was wrong in law and/or unjust on the following grounds:

a. It fails to give effect to and/or subverts the purpose of the statutory scheme set up under section 203 of [the 1990 Act];

…

c. The decision to make the order is premised on a failure to identify and/or answer three key questions that must be posed and answered before a decision can lawfully be reached as to whether compensation is payable, namely (i) were there reasonable steps that could have [been] taken to avert the loss? (ii) was the loss that occurred attributable to the failure to take those reasonable steps? [(iii)] was that loss reasonably foreseeable?"

5. Lewison L.J. regarded those two grounds as properly arguable. Logically, in my view, ground 1(c) is prior to ground 1(a). So the two main issues for us to decide are, in this order:

(1) Did the Tribunal fail to identify and answer the relevant questions under article 9(4)(c) of the TPO (ground 1(c))?

(2) Did the Tribunal fail to give effect to the purpose of the statutory scheme (ground 1(a))?

Section 203 of the 1990 Act

6. Section 203 of the 1990 Act, under the heading "Compensation in respect of tree preservation orders", provided, so far as is relevant here:

"A tree preservation order may make provision for the payment by the local planning authority, subject to such exceptions and conditions as may be specified in the order, of compensation in respect of loss or damage caused or incurred in consequence –

(a) of the refusal of any consent required under the order …

… ."

7. In England, section 203 was repealed by sections 192(6) and 238 of, and Schedule 13 to, the Planning Act 2008, with effect from 6 April 2012. Transitional arrangements were put in place under section 193 of the 2008 Act.

Article 9 of the TPO

8. Article 9 of the TPO provides:

"(1) If, on a claim under this article, any person establishes that loss or damage has been caused or incurred in consequence of –

(a) the refusal of any consent required under this Order;

…

he shall, subject to paragraphs (3) and (4), be entitled to compensation from the authority.

…

(4) In any case, [other than refusal of consent for felling in the course of forestry operations], no compensation shall be payable to a person –

…

(b) for loss or damage, which, having regard to the statement of reasons submitted in accordance with article 6(c) and any documents or other evidence submitted in support of any such statement, was not reasonably foreseeable when consent was refused or was granted subject to conditions;

(c) for loss or damage reasonably foreseeable by that person and attributable to his failure to take reasonable steps to avert the loss or damage or to mitigate its extent;

… ."

9. Provisions equivalent to those of article 9(4)(c) are contained in regulation 24(4)(c) of the Town and Country Planning (Tree Preservation) (England) Regulations 2012.

The evidence before the Tribunal

10. For the hearing before the Tribunal the parties produced a Statement of Facts and Issues. In that document they described the "overarching issue" in the case in this way: "whether because the Compensating Authority refused to consent to the removal of an oak tree protected by a TPO, the Claimants are entitled to compensation for loss and damage to a conservatory attached to the rear of their house". Among the issues identified by the council were "[whether] dehydration by the oak of the subsoil under the site for the conservatory and the risk of consequential movement of the conservatory and consequential damage were reasonably foreseeable to the Claimants before May 2003" (paragraph 84); "[if] they were, whether the Claimants' loss or damage is attributable to their failure to take reasonable steps to avert loss or damage" (paragraph 85); and "[whether] on-going dehydration of the subsoil by the oak in the summer months and the risk of consequential on-going further movement of the conservatory and damage was reasonably foreseeable to the Compensating Authority when it refused consent in May 2010" (paragraph 87).
11. The Tribunal heard the expert evidence of two witnesses called on behalf of Mr and Mrs Burge – Mr Robert Evans, a chartered engineer, and Mr Andrew Wyse, a subsidence consultant, and of a single witness called on behalf of the council – Mr Kenneth Brown, a chartered engineer. The Tribunal had before it Mr Evans' report dated 13 January 2016, Mr Wyse's witness statement dated 8 February 2016, and Mr Brown's report dated 22 January 2016. The Tribunal also had before it witness statements made by Mr and Mrs Burge, Mr Burge's made on 5 February 2016, Mrs Burge's on 4 February 2016.
12. In his witness statement Mr Burge said nothing about the construction of the conservatory. He said that he and Mrs Burge had first noticed the damage to the house and the conservatory "in the summer of 2006" (paragraph 12). He went on to describe the progress of movement and damage to the conservatory, which continued after the removal of other trees in January and September 2007, leading "Crawfords [the loss adjusters] to conclude that the Oak tree was the cause of the continuing movement" (paragraph 14). He then described the history behind the claim, including the unsuccessful attempt that was made to find out who owned the oak tree (paragraphs 15 and 16), the making and confirmation of the TPO (paragraph 17), the council's refusals of consent to fell the oak tree (paragraph 18), and the remedial work to the conservatory (paragraphs 20 to 23). In her witness statement Mrs Burge agreed with the evidence in Mr Burge's, without adding to it.
13. In May 2016 Mr Evans and Mr Brown had produced a joint statement on engineering matters, recording areas of agreement and disagreement between them after a meeting on 21 April 2016. Among other things, they agreed that "due to the depth of the foundations, some distortion and cracking of the conservatory might have occurred" (point 3); that "proper Engineering advice [would] have been to construct the foundations to the conservatory in accordance with the NHBC guidelines" – though Mr Evans observed that "this was not the industry standard for conservatories" (point 8); that "[given] the restricted location of the site, a piled foundation was the most appropriate foundation solution for the rebuilding of the conservatory" (point 9); that the "costs of the works of the order of £29,347.01" appeared "reasonable" – though Mr Brown was of the view that "if partial underpinning had proved successful the overall costs would have been significantly less" (point 12); and that "the depth [of foundations to the conservatory] should have been of the order of between 2.4m and 2.8m below ground level in order to allow for the drying effects of the eucalyptus and oak trees which were both present at the time of construction" – though Mr Evans observed that "[this] requirement would have applied only if the industry standard for conservatories was compliance with NHBC Appendix 4.2, which it was not" (point 14).
14. There was disagreement on the question of whether the "depth of foundation to the conservatory [should have been] in accordance with the NHBC guidelines" (point 5); on the question of whether "the conservatory [should] have been constructed on foundations designed to resist the effects of the Oak tree" (point 10); on the question of "what options were available to restore stability to the conservatory" once consent to fell the oak tree had been refused, Mr Brown contending that "[if] the conservatory was built on a raft it may have been possible to form movement joints and allow it to move independently of the house …", Mr Evans that "the only available course of action was to demolish the conservatory and to build a new conservatory off foundations capable of accommodating the effects of the remaining Oak tree …" (point 11); and on the question of whether, if "[the] conservatory was built on a raft", it would have been appropriate to provide "movement joints" (point 13).

The Tribunal's decision

15. The Tribunal recorded the council's contention that "the case raised an important point, namely whether there is an obligation to pay compensation for damage to a building which was not constructed in accordance with relevant industry guidance concerning the potential for tree root subsidence in an area of plastic clay". The council had maintained that "the conservatory was so inadequately constructed that it would have failed anyway, regardless of the presence of trees, but if that is not accepted[,] it was reasonably foreseeable to [Mr and Mrs Burge] that a conservatory which did not comply with the relevant industry guidance concerning construction in areas of plastic clay would in due course suffer damage, and thus no compensation is payable" (paragraph 4 of the Tribunal's decision).
16. In the light of the evidence, including the agreed matters in the Statement of Facts and Issues, the Tribunal made a number of findings of fact. Its findings of fact relating to the construction of the conservatory were these (in paragraphs 10 to 12 of its decision):

"10. The claim property was constructed in 1994 as part of a housing estate scheme on a reasonably level site with no unusual topographical features. …

11. The claim property was purchased by the claimants in May 1997. … In about May 2003, a conservatory was built and attached at the rear and right side of the house. The house has foundations totalling 1.2m in depth. The conservatory, when first built (it has since been replaced as we outline below), had foundations of 0.4m. The property is sited on clay soil, having plasticity indices of between 39% and 50% which means it has a high shrink/swell characteristic.

12. By 2006, a number of trees and shrubs were in the vicinity of the claim property. In the front garden was a false Acacia tree, approximately 5m high and about 5.5m away from the front of the house. In the rear garden there was a eucalyptus tree, 5m away, and with an estimated height of about 10m, and a conifer, 2m away and about 6m in height. The Oak is situated on land beyond the rear boundary of the claim property, adjoining its rear garden. It is about 13m away and 8-11m high. It was assessed in September 2009 to be significantly older than the claim property. There are also hawthorn trees in the area. In the rear garden of No.29 Saxon Way there was a magnolia tree, about 2.5m away and about 4m high."

17. The Tribunal went on to make its findings of fact on the ensuing events, from the time when damage to the conservatory was first noticed in mid-2006 to the making of the TPO, and its confirmation in June 2008 (in paragraphs 13 to 20):

"13. In early Summer 2006, the claimants noticed cracks in the rear wall of the house and between the house and the conservatory. They reported this to their insurers, Axa Insurance Plc, who appointed loss adjusters, Crawford & Co. to investigate and deal with the claim. Mr Wyse of the company's National Subsidence Unit visited the property on 1 November 2006 and in a report dated 2 November 2006 recorded that there were two areas of damage, one to the conservatory and one to the left rear corner of the house and in both areas there was cracking of 5mm or more which Mr Wyse categorised as moderate. He also said that "there are several trees and shrubs nearby, some with roots that may extend beyond the house foundations". He noted that the eucalyptus and conifers were of particular interest and in relation to the damage to the house he expressed a view that the cause appeared to be clay shrinkage which was root-induced. In relation to the damage to the conservatory, Mr Wyse was more cautious and said that the cause was not clear to him from the information that he had. He thought it could be clay shrinkage due to shallow foundations or drainage problems and he recommended site investigations.

14. These investigations were carried out by a company called Mat Lab in December 2006 which included CCTV drain surveys and the digging of four exploratory trial pits.

15. It is common ground that the cracking to the house was caused by the eucalyptus tree which has since been felled and the claimants made no claim for this. The trial pits near to the conservatory revealed roots of an oak tree or sweet chestnut together with some unidentifiable roots together with small conifer roots. In the Summer of 2007, bore holes were drilled to a depth of 4m close to the conservatory. In respect of one bore hole, roots from oak, and to a lesser extent hawthorn and some surface grass were detected. In the other bore hole roots from magnolia and to a lesser extent oak and another species were detected. The moisture content of the soil from the bore holes was tested and ranged from 30%-35% with the soil type being confirmed as clay.

16. In or before September 2007 the property was inspected by the Marishal Thompson Group, which confirmed that the conservatory was rotating away from the junction with the house and stated:

"In our opinion [the Oak] will be exerting a significant influence across the whole of the rear elevation including the conservatory. Removal of this tree subject to heave assessment will help promote the restoration of stability of the currently affected areas. The influence of [the magnolia] is very much secondary to that of [the Oak]."

17. The report went on to say that pruning alone should not be considered as an effective alternative arboricultural solution and that removal was the only effective form of mitigation. The report accordingly recommended the removal of the magnolia and the Oak.

18. In September 2007 Mr Wyse prepared an addendum technical report in which he said that the underlying soil was shrinkable clay, with a significant moisture content deficit and swelling potential below foundation depth, confirming the soil below the foundations to be desiccated. He said that "the damage to the conservatory has also been proved to have been caused by clay shrinkage subsidence as a result of moisture obstruction by nearby trees/vegetation". He recommended removal of trees and said that once they had been removed, the ground would rehydrate over the winter and closure of the cracks would occur. Once this process was complete Mr Wyse said that his firm would prepare a schedule of repairs for the two areas of the building that had been damaged.

19. In September 2007 the conifer in the garden of the property was removed and in or around April 2008 the magnolia in the garden of No.29 was removed.

20. The TPO was made on 13 December 2007 and confirmed on 4 June 2008."

18. The Tribunal then set out its findings of fact on the subsequent history leading up to the claim for compensation being served on the council in July 2010 (in paragraphs 21 to 25):

"21. Following the removal of the conifer and magnolia, movement to the conservatory continued, implicating the Oak as a continuing contributory cause of the movement. On 2 September 2008 the Marishal Thompson Group made an application on behalf of the claimants to the council to remove the Oak which was refused on 3 October 2008 on the basis that the council took the view that there was then insufficient evidence to implicate the Oak.

22. On 16 October 2008 level monitoring was commenced and on 30 September 2009 further soil samples were taken. Results from the monitoring showed that in the absence of the eucalyptus, conifer and magnolia, but in the continued presence of the Oak, ongoing movement to the conservatory was present but which was seasonal.

23. On 1 April 2010 the council received Marishal Thompson's application to remove the Oak, stating that this tree had been implicated as a contributory factor in subsidence damage relating to clay shrinkage. The application included an arboricultural report, an engineer's report, foundation details, soil analysis, root identification, a drainage report and level monitoring results.

24. On 28 May 2010 the council refused permission to remove the Oak as its removal would "have a detrimental impact on the existing and future visual amenity of the locality and would be detrimental to the character of the local landscape and wider contexts and would be contrary to National Policy, PPS[1] and Policy L1 of the South Gloucestershire Local Plan (Adopted) 2006."

25. On 5 July 2010 solicitors for the claimants served on the council a claim for compensation."

19. Finally, the Tribunal recorded its findings of fact on events after the claim was served (in paragraphs 26 to 30):

"26. In August 2010 Mr Evans visited the property. In his view the cracking had widened significantly since Mr Wyse had taken photographs in 2006. Mr Evans was of the view that the pattern of cracks and distortions showed that the primary mechanism of movement was rotation of the conservatory away from the house caused by downward movement at its rear wall with maximum movement at the rear left corner closest to the Oak.

27. On 3 March 2011 the council advised, in an open letter, that it was prepared to compensate for additional costs incurred by the claimants as a result of their refusal of consent, limited to the cost of upgrading any foundation works beyond that necessary to repair the original damage and that necessary to protect against any future damage caused by heave. …

…

29. … On 19 July 2011 the compensating authority denied liability on the basis that the property was not designed or constructed to comply with NHBC guidance.

30. In February 2013 works to take down and reinstate the conservatory with piled foundations commenced and they were completed in about April or May 2013."

20. Under the heading "Issues", the Tribunal observed (in paragraph 33) that it was "common ground that the damage to the conservatory … was caused by the roots from the Oak, rather than any other trees". It recorded (in paragraph 34) the two bases on which the council had resisted the claim: first, "that the foundations to the original conservatory were wholly inadequate, to the extent that they would have failed in any event"; and second, "[further], or alternatively, that when the conservatory was constructed in 2003, it was in the full knowledge of a) the presence and distance of the Oak, and b) its status as a tree retained as part of the scheme for its substantial amenity value".
21. In the part of its decision headed "Discussion", the Tribunal went on to say (in paragraph 37) that it was "for the claimants to establish that loss or damage has been caused or incurred as a consequence of the council's refusal to give consent to fell the Oak, a consent that was required as a result of the TPO"; and that "[the] burden of proof is on the claimants, and the standard of proof is the normal civil standard, that is the balance of probabilities". It said it had "no doubt" that Mr and Mrs Burge had satisfied it on this question. The conservatory had been "damaged by the roots of the Oak", and "in refusing consent to fell the Oak [sic], further damage was caused". This, said the Tribunal, seemed "relatively uncontroversial, indeed common ground, and it follows that the claimants are prima facie entitled to compensation" (paragraph 38).
22. The Tribunal proceeded to deal with the two contentions put forward by the council in resisting the claim for compensation, the first based on article 9(4)(b) of the TPO, the second on article 9(4)(c). Before doing so, it reminded itself that "[in] order to deny compensation that is otherwise payable, it is for the council to prove, on the balance of probabilities, that one or other of these instances applies" (paragraph 39).
23. The council's reliance on article 9(4)(b) failed. On that part of the council's case, the Tribunal said (in paragraph 40):

"40. The council contends that the claimants' loss or damage was not reasonably foreseeable when consent was refused: Article 9(4)(b) of the TPO. That is a difficult argument to sustain. Consent was refused in 2010, by which time it was apparent to all that the Oak was causing significant damage to the foundations of the conservatory. We do not consider that the council comes anywhere near satisfying us that further loss or damage to the claimants was not reasonably foreseeable at that date. On the contrary, we accept the [claimants'] contention that the Oak was a substantial and effective cause of the real risk of on-going and future movement of the conservatory."

24. Turning to the council's case on article 9(4)(c), the Tribunal said this (in paragraph 41):

"41. The council contends, in the alternative, that the claimants' loss or damage was reasonably foreseeable by the claimants and attributable to their failure to take reasonable steps to avert the loss or damage or to mitigate its extent: see Article 9(4)(c) of the TPO. The basis of this contention is that the foundations of the conservatory were so inadequate, being of insufficient depth taking account of the relevant building standards, that they would have failed anyway. The council argues that, when the conservatory was built in 2003, it would have been reasonably foreseeable from the proximity of the Oak to the conservatory that loss or damage would ensue. No reasonable steps were taken to avert that loss or damage, for example by building deeper foundations."

25. The Tribunal set out its findings and conclusions on the evidence it had heard about the depth of foundations (in paragraphs 42 to 44):

"42. The issue of the depth of foundations was investigated in the course of the hearing. The criticism made by the council, that the foundations of the conservatory were too shallow taking account of the ground conditions and the proximity of trees, is not contested by the claimants. Both experts (Mr Evans and Mr Brown) agreed … that due to the depth of the foundations, some distortion or cracking of the conservatory might have occurred … . Both experts agreed that proper engineering advice would have been to construct the conservatory in accordance with the NHBC Guidelines, Mr Evans qualifying this by noting that this was 'not the industry standard for conservatories.'

43. There was as a result some exploration of the appropriate standard in the course of the hearing. Mr Brown had made reference in his Report to the NHBC Standards operative from October 1992, Chapter 4.2 of which deals with 'Building near trees'. It states … at D4 that 'The design shall make allowance for the effect of trees in shrinkable soils', indicating that the species and mature height of the tree was an item to be taken into account, Oak trees themselves having a high water demand. It states … at D5 that 'Foundations shall be designed to transmit loads to the ground safely and without excessive movement' and continues:

"Irrespective of any foundation depths derived from this Chapter, all foundations should be constructed on soils capable of supporting the imposed loads. For foundations near trees, the depth should be established in relation to:

water demand and mature height of trees

movement potential of soils[.]

Design of foundations to all permanent constructions, including those to dwellings, garages, porches, etc, should take account of the effects of soil desiccation caused by previous or existing trees and trees which are scheduled to be planted."

44. Mr Evans sought to argue that this did not apply to conservatories, and it is right that when the NHBC Standards were reviewed in 2003, conservatories were included for the first time in the list of 'permanent constructions'. He therefore contended that at the time that the claimants' conservatory was built, there were no requirements for conservatories to comply with Building Regulations unless they formed part of a habitable room (which the claimants' conservatory did not). It was not until 2007 that the Guide to Good Practice in the Specification and Installation of Conservatories within the UK published by the Glass and Glazing Federation recommended that conservatories should comply with Chapter 4.2 of the NHBC Standards."

26. The Tribunal concluded its discussion of the council's case on article 9(4)(c) of the TPO in this way (in paragraphs 45 and 46):

"45. We do not consider that this discussion advanced matters very far. We are prepared to accept that insofar as a particular conservatory was a permanent construction it would fall within the scope of the 1992 NHBC Standards and that the 2003 amendment merely clarified the existing position. We cannot see that there is a meaningful distinction to be drawn in this respect between, for example, porches and conservatories. But whether or not the claimants' conservatory complied with the requisite building standards is in our view immaterial. It is accepted, as we have noted, that its foundations were too shallow, and that the builders should have dug them deeper. We do not see how that reflects adversely upon the position of the claimants with regard to the case being advanced by the council. Applying Article 9(4)(c) of the TPO, it is necessary to consider the position in 2003 immediately before and at the time of the erection of the conservatory. The question is whether at that time loss or damage to the conservatory being erected was reasonably foreseeable to the claimants themselves. It is for the council to show that the claimants knew, or ought to have known, that there was a real risk of the Oak tree causing subsidence damage to the new conservatory.

46. In our judgment, the council has failed to show this. There is no evidence that the claimants knew the depth of the foundations, the proximity of the Oak, or for that matter its potential effect in terms of subsidence damage of its proximity to the conservatory being built. The claimants employed professional contractors to build the conservatory and as far as is known put their faith in those so employed as they were perfectly entitled to do."

27. In its "Conclusions" the Tribunal addressed the council's contention that the case had "major implications for compensating authorities" (paragraph 47), and expressed this view (in paragraph 48):

"48. This argument based on policy does not, however, sit at all comfortably with the facts of this case. The conservatory was built in 2003 at a time when there were no protected trees in the vicinity. The TPO protecting the oak was made in 2007, confirmed the following year, and consent to fell was refused in 2010. We do not see how it can sensibly be argued that the claimants have sought from the outset to use the compensatory machinery available to those affected by TPOs to their personal advantage and to the disadvantage of taxpayers generally."

Did the Tribunal fail to identify and answer the relevant questions under article 9(4)(c) of the TPO (ground 1(c))?

28. For the council, Mr Satnam Choongh submitted that the Tribunal failed to identify and answer the questions which ought to have been dealt with under article 9(4)(c) of the TPO. The Tribunal's self-direction in paragraph 45 of its decision was correct. But in paragraph 46 it fixed only on the question of whether Mr and Mrs Burge actually did know of the risk, rather than on the question of whether they ought to have known of it, and did what they reasonably could to avoid or mitigate the loss. To establish whether the exception under that provision applied, it was necessary for the Tribunal to tackle at least three questions – namely, whether the council had demonstrated, first, that the loss or damage was "reasonably foreseeable" by Mr and Mrs Burge; secondly, that there were "reasonable steps" they could have taken to avert the loss or damage or to mitigate its extent; and thirdly, if so, that the loss or damage was attributable to their failure to take those "reasonable steps".
29. It was clear, Mr Choongh submitted, that if the Tribunal had addressed those questions in the light of its findings of fact, the answers would have been, first, that the loss or damage was indeed "reasonably foreseeable" by Mr and Mrs Burge, in that they knew, or at least ought to have known, that if a building – here the conservatory – was not built in accordance with relevant building standards, so that its foundations are too shallow, it was likely to suffer damage such as occurred in this case; secondly, that there were "reasonable steps" they could have taken to avert the loss – in particular, ensuring the conservatory was built with adequate foundations, in accordance with relevant standards; and thirdly, that the loss or damage had occurred because Mr and Mrs Burge's contractors had built the conservatory with defective foundations. The council did not have to demonstrate that Mr and Mrs Burge were themselves aware of the relevant building standards, the appropriate depth of foundations, the possible effects of tree roots on a building if constructed with inadequate foundations in particular soil conditions, and so forth. That, said Mr Choongh, is more than article 9(4)(c) requires.
30. On behalf of Mr and Mrs Burge, Mr Jason Evans-Tovey submitted that the Tribunal's approach was sound, and that its conclusions in paragraphs 45 and 46 were sufficient to dispose of the questions arising under article 9(4)(c). On the evidence, the conclusions it reached were absolutely right. Indeed, there was no evidence to support any other conclusions.
31. Read together, Mr Evans-Tovey submitted, paragraphs 45 and 46 of the Tribunal's decision show that it did tackle the questions raised by article 9(4)(c). It asked itself whether, at the time the conservatory was built, the loss or damage was "reasonably foreseeable to the claimants themselves" (paragraph 45). In its view the council had failed to discharge the burden of proving that Mr and Mrs Burge "knew, or ought to have known" of the risk (paragraph 46). Its reasons for that conclusion, introduced by the words "[there] is no evidence that the claimants knew", were clear and appropriate. Therefore, submitted Mr Evans-Tovey, it is quite clear that the Tribunal did consider the question of the reasonable foreseeability of the loss or damage in this case, and did conclude that the relevant loss was not "reasonably foreseeable" and that, by employing "professional contractors", Mr and Mrs Burge had taken "reasonable steps to avert the loss or damage or to mitigate its extent".
32. Mr Evans-Tovey emphasized the requirement in article 9(4)(c) that the loss or damage must have been reasonably foreseeable "by that person", which is the person claiming compensation – and not, as the council had argued before the Tribunal, whether it was "reasonably foreseeable by [his or her] specialist agents". It was therefore necessary to consider whether the loss or damage – here, the damage caused or incurred in consequence of the council's refusal to fell the oak tree – was "reasonably foreseeable" by that particular person – here, Mr and Mrs Burge. The relevant loss or damage was "the on-going or continuing impairment of the load-bearing qualities of soil beneath the foundations of the claim property (by the continuing dehydration and inhibition of rehydration by the roots of the Oak) …". The test, Mr Evans-Tovey submitted, is a subjective one. It could only be satisfied if the person suffering the damage in question had "actual or imputed knowledge" of the relevant matters – including, in this case, "the type of soil at foundation level; that certain clays have significant volumetric-change potential depending on moisture content; rooting distances, depths and/or patterns for particular types of trees; the 'water demands' of particular types of trees; the likely effects of particular tree roots on particular clay sub-soils and at particular depths (if any)" (paragraph 29 of Mr Evans-Tovey's skeleton argument). The reasonable steps were those that a reasonable person in the position of the claimant would have taken. There was nothing in article 9(4)(c) to suggest that the person in question was not free to do what most property owners would have done in the circumstances, which was to "exercise reasonable skill and care by delegating matters to a competent third party". Under article 9(4)(c) the "reasonable steps" required did not fall within the limited category of non-delegable obligations (see Clerk & Lindsell on Torts, 21^st edition, paragraphs 6-63 to 6-74).
33. On the evidence in this case, Mr Evans-Tovey submitted, it was not open to the Tribunal to conclude that the loss or damage was "reasonably foreseeable" by Mr and Mrs Burge at the relevant date, which was when the conservatory was constructed in May 2003. The TPO was not then in place, and indeed was not confirmed until 2008, and consent to fell the oak tree was not refused until 2010. But in any event, there was no evidence before the Tribunal that any of the relevant matters were, in May 2003, "reasonably foreseeable" to Mr and Mrs Burge themselves, as opposed to what ought to have been "reasonably foreseeable" to reasonably competent builders. There was, in fact, no evidence that Mr and Mrs Burge themselves had actual knowledge of any real risk of the oak tree causing subsidence to the conservatory, and no evidence that they had any relevant "special knowledge" of their own. Nor was there any evidence to support a conclusion that they had failed to take reasonable steps to avert the loss or damage. The council could have required them to be called for cross-examination on the evidence in their witness statements, and in particular on what they did and what they knew at the relevant time. But it did not do that.
34. In my view, persuasively as Mr Evans-Tovey put his submissions in defence of the Tribunal's approach, I cannot accept them.
35. Before the Tribunal both parties referred to jurisprudence in the law of tort, in particular in the law of nuisance, including the decision of the House of Lords in Delaware Mansions Ltd. v Westminster City Council [2002] 1 AC 321 (in particular, the speech of Lord Cooke of Thorndon, at paragraphs 32 to 34), and the decision of Mr Roger Toulson Q.C., as he then was, sitting as a deputy judge of the High Court, in Paterson v Humberside County Council [1996] Const. L.J. 64 (in particular, at pp.66 to 71 of his judgment). Those authorities did not feature prominently in the submissions made in the appeal. And I do not think they bear significantly on the issues that arise in this appeal in the context of the statutory scheme for tree preservation orders, and the particular provisions with which we are concerned. We must concentrate on those provisions and the provisions of the TPO itself, and on their operation in the particular circumstances of this case.
36. The provisions of article 9 of the TPO relate specifically to "loss or damage" that has been "caused or incurred in consequence of … the refusal of any consent required under [the TPO]". There are two relevant exclusions of the entitlement to compensation under these provisions, respectively in article 9(4)(b) and (c). They are not in exactly parallel terms. And that seems to me to have been deliberate. The exclusion of compensation in article 9(4)(b) is specific as to the date at which the relevant "loss or damage" was or was not "reasonably foreseeable" by the compensating authority. The specific point in time at which the question falls to be considered under that provision is "when consent was refused or was granted subject to conditions". There is no such specification of date in article 9(4)(c). In that provision there is no temporal restriction on the consideration of whether or not the "loss or damage" was "reasonably foreseeable" by the person in question, and "attributable to his failure to take reasonable steps to avert [it] or to mitigate its extent". The scope of the enquiry as to reasonable foreseeability and the taking of reasonable steps to avert or mitigate the relevant loss or damage is not fixed in time for every case. It is left to the Tribunal to determine in the particular circumstances of the case it is considering. The Tribunal is not required to confine its attention to a specific date, which might lead to an overly restrictive consideration of the questions of reasonable foreseeability and reasonable steps. It is free to consider these questions within the relevant span of time – bearing in mind always that the relevant "loss or damage" it is considering is the "loss or damage" flowing from the refusal of consent or the granting of consent subject to conditions. To read into article 9(4)(c) some particular date on which the enquiry must focus would be contrary to its natural and proper construction.
37. In my view it is neither appropriate nor indeed possible to prescribe, for all cases, what the relevant span of time will be. Circumstances will differ widely. The point at which the actual "loss or damage" crystallizes will be different from one case to the next. In some cases the potential for such "loss or damage" to occur will have emerged before, perhaps long before, the actual refusal of consent, often before the making and confirmation of the tree preservation order itself. In others, that will not be so. Sometimes a tree preservation order will have been made and confirmed before the potential for relevant "loss or damage" arises. Sometimes the relevant loss or damage will become apparent only after consent to fell is refused. The ambit of the relevant enquiry as to reasonable foreseeability and reasonable steps will vary accordingly. It will depend on the particular circumstances of the case in hand, and will be, in every case, for the Tribunal to resolve as a matter of fact and judgment – so long as it directs itself appropriately under the provisions governing the decision it has to make.
38. The basic principle at work here is that the claimant for compensation, in this instance the claimant seeking compensation under the statutory scheme for tree preservation orders, is under a duty to mitigate his loss. A useful discussion of this duty in the particular context of the statutory scheme for tree preservation orders is to be found in section 25.6 of Charles Mynors' "The Law of Trees, Forests and Hedges" (2^nd edition). As stated by Lord Nicholls of Birkenhead in Director of Buildings and Lands v Shun Fung Ironworks Ltd. [1995] 2 A.C. 111 (at p.126), the general principle is this:

"… The law expects those who claim recompense to behave reasonably. If a reasonable person in the position of the claimant would have taken steps to eliminate or reduce the loss, and the claimant failed to do so, he cannot fairly expect to be compensated for by the loss or the unreasonable part of it. Likewise if a reasonable person in the position of the claimant would not have incurred, or would not incur, the expenditure being claimed, fairness does not require that the authority should be responsible for such expenditure. …".

39. In this case both parties seem to have thought that the relevant enquiry as to reasonable foreseeability and reasonable steps under article 9(4)(c) began and ended with the construction of the conservatory in May 2003, rather than embracing a period that extended forward from that time, at least to the point at which the relevant "loss or damage" was "caused or incurred in consequence … of the refusal of … consent required under [the TPO]". And it is also clear, from paragraph 45 of the Tribunal's decision, that the Tribunal itself thought it necessary only "to consider the position in 2003 immediately before and at the time of the erection of the conservatory", so that the question was whether "at that time" the "loss or damage" to the conservatory was "reasonably foreseeable" to Mr and Mrs Burge. Whatever one makes of what the Tribunal said in paragraph 46, it is quite plain from paragraph 45 that it was restricting its conclusions on the matters that fell for consideration under article 9(4)(c) solely to the position as it was when the conservatory was built in May 2003.
40. In my view, in the particular circumstances of this case, that was to impose an artificial constraint on the consideration of reasonable foreseeability of the relevant "loss or damage" and reasonable steps "to avert [it]" or "to mitigate its extent". The Tribunal should not, I think, have confined itself to that single point in time – when the conservatory was built – even though the parties seem to have agreed that that was the critical date. It ought to have considered the questions of reasonable foreseeability and reasonable steps having regard to the whole period between the construction of the conservatory and the relevant "loss or damage" being "caused or incurred". Only then could it fully address the matters that had to be dealt with under article 9(4)(c).
41. Little if any material was before the Tribunal to shed light on the circumstances in which the conservatory was erected in 2003. As to what instructions were given to the contractors who constructed it, their experience and competence as builders, how they came to build the foundations in the way they evidently did, and any dealings Mr and Burge later had with them once the damage to the conservatory had begun to emerge, the evidence could best be described as scant (see paragraph 12 above). But there was substantial and undisputed evidence, which the Tribunal accepted, that regardless of what Mr and Mrs Burge actually knew or ought to have known before then, the damage to the conservatory had become apparent in mid-2006; that by September 2007 it had been confirmed both that the oak tree was, or was likely to be, responsible for the movement of the conservatory away from the house and also that its removal would "help promote the restoration of stability of the currently affected areas"; that the movement continued, "implicating the Oak as a continuing contributory cause of the movement"; and that the damage to the conservatory worsened both before the council refused its consent to fell the oak tree, and afterwards (see paragraphs 17 and 18 above). These were, I think, important elements of the evidential picture before the Tribunal, and relevant to the specific questions that had to be dealt with under article 9(4)(c) – not only to the question of the reasonable foreseeability of the relevant "loss or damage" but also to the question of "reasonable steps" being taken, or not being taken, to "avert" that loss or damage, and to "mitigate its extent". What those steps might be in any particular case – such as the monitoring of ongoing cyclical movement, appropriate remedial works to underpin the building in question, or the timely felling of trees – will be for the Tribunal to consider in the light of all the evidence before it (see, for example, Fletcher v Chelmsford Borough Council [1991] 63 P. & C.R. 312, and Wright v Horsham District Council [2011] UKUT 319 (LC)).
42. There is – I think rightly – no criticism of the Tribunal's self-direction in paragraph 45, as far as it goes. In dealing with the question of reasonable foreseeability, the Tribunal was clearly conscious of the need to make appropriate findings as to what Mr and Mrs Burge "knew, or ought to have known" at the relevant time. And, on that particular question, the Tribunal also reminded itself, again correctly, that it was "for the council to show" that, at the relevant time, "the claimants knew, or ought to have known, that there was a real risk of the Oak tree causing subsidence damage to the … conservatory".
43. But there are, it seems to me, three difficulties with the Tribunal's shortly expressed but crucial conclusions in paragraph 46.
44. First, the temporal focus of those conclusions was, as I have said, too narrow. On the agreed evidence, even before the TPO was made in December 2007, and some 12 months before the first application for consent to fell the oak tree was submitted to the council in September 2008, the tree had been identified as a likely significant cause of the ongoing movement and damage to the conservatory. Nor was there any disagreement as to the sequence of events from that point on, leading to the council's second refusal of consent for the felling of the tree in May 2010, and also beyond then. By isolating May 2003 as the single relevant date for its consideration of the questions raised under article 9(4)(c), some seven years before the council's second refusal of consent to fell, I think the Tribunal prevented itself from deciding the issue of mitigation of loss in the wider sense prescribed under that provision – both the question of the reasonable foreseeability of the relevant loss or damage and also the question of whether reasonable steps had been taken to avert that loss or damage and to mitigate its extent. In this respect, I think the approach it adopted was wrong. Of course, if it had dealt with the issue correctly it might still have concluded, even taking account of everything that had happened after May 2003, that the council had not succeeded in demonstrating a failure by Mr and Mrs Burge to discharge their duty to mitigate. But that was a matter for the Tribunal to decide on the evidence before it, not for this court in the appeal.
45. Secondly and in any event, even if one were to accept as valid and sufficient the narrow temporal focus taken by the Tribunal, there is in my view a real doubt that its reasons in paragraph 46 deal squarely with the question of reasonable foreseeability in the sense of what Mr and Mrs Burge ought to have known as well as what they did in fact know.
46. One can, I think, overlook the superficially surprising finding – on what would surely be an over-literal reading – that Mr and Mrs Burge did not know of "the proximity of the Oak". To criticize the Tribunal for that infelicity would be unfair. On a sensible reading, it must, I think, have meant to refer to the proximity of the roots of the oak tree to the ground on which the conservatory was to be built. The presence of trees in the vicinity – including the oak tree – was, of course, quite obvious. But the criticism with some real force here is that the Tribunal's findings in paragraph 46 are expressed in terms of what Mr and Mrs Burge in fact knew and did, as opposed to what they ought to have known and done. The second sentence of the paragraph is entirely concerned with what Mr and Mrs Burge actually knew, or rather what they did not know – first, "the depth of the foundations", second, "the proximity of the Oak", and third, "its potential effect in terms of subsidence damage of its proximity to the conservatory being built". The final sentence is concerned with what they actually did – first, "employed professional contractors to build the conservatory", and second, "as far as is known put their faith in those so employed as they were perfectly entitled to do". Only that last clause – "as they were perfectly entitled to do" – might be seen as a conclusion on the question of reasonable foreseeability. But the Tribunal's reasoning in paragraph 46, read fairly as a whole and together with paragraph 45, does not, in my view, show that the specific questions arising under article 9(4)(c) had been properly grappled with.
47. Thirdly, and again in any event, whilst there will probably be many cases in which the Tribunal, in deciding whether a compensating authority has demonstrated that relevant loss or damage was reasonably foreseeable by a claimant for compensation, may justly conclude that it would not be right to attribute to him the reasonable foresight of his contractor or "specialist agents", a conclusion to that effect can only be reached after the particular circumstances of the case have been properly considered in the light of all the available evidence. And in this case I cannot accept that that was done.
48. I would not wish to lay down any general rule about the circumstances in which such a conclusion may be justified. And indeed that would be impossible. A claimant will not always be able to avoid the conclusion that the relevant loss or damage was reasonably foreseeable by him, though not actually foreseen, in spite of there being no direct evidence on the question either from the claimant himself or from the contractor who did the work for him – or for a predecessor in title. In some cases it will be quite obvious from the outset that the contractor has undertaken the work incompetently or without proper care, and that this either was or should have been apparent to the claimant himself straight away. In others, the shortcomings in the contractor's work may go unnoticed until after the loss or damage has occurred. And in others again, such defects may emerge only some time after the work was done, but before the loss or damage occurs. Inadequate foundations for a building may be a good example. In cases falling within the second and third categories, the Tribunal may or may not be able to find that the loss or damage was reasonably foreseeable by the claimant. But a finding that it was not reasonably foreseeable by him in such circumstances, simply because the work in question was done not by the claimant himself but by a contractor, is not inevitable or automatic.
49. None of this takes away from the burden resting on a compensating authority to demonstrate to the Tribunal's satisfaction that the loss or damage was reasonably foreseeable by the claimant, and that the claimant has failed to discharge his duty to mitigate his loss. But that burden should not be exaggerated. The absence of reasonable foreseeability by a claimant of the loss or damage flowing from the refusal of consent to fell a tree protected by a tree preservation order may often be more difficult to prove than the claimant's failure to take reasonable steps to avert the loss or damage or his failure to mitigate its extent. Much may turn on sensible inferences drawn from slender evidence, or even from the absence of relevant evidence.
50. In this case, I accept, it might have been open to the Tribunal to find, on the evidence presented to it, including the agreed evidence, that the loss or damage for which Mr and Mrs Burge were claiming compensation was not reasonably foreseeable by them at any relevant time. But such a finding was not, in my view, the only finding open to it. Assuming for the moment that the final sentence of paragraph 46 of the Tribunal's decision contains its essential conclusion on the question of reasonable foreseeability – as Mr Evans-Tovey submitted it does – it is hard to escape the impression that the Tribunal found as it did simply because Mr and Mrs Burge had "employed professional contractors to build the conservatory", and on the basis that it was enough for them – "as far as is known" – to have "put their faith in those so employed as they were perfectly entitled to do".
51. Without more, this seems to imply that in the Tribunal's view the mere fact that Mr and Mrs Burge had entrusted the building of the conservatory to contractors was enough in itself to overcome the council's case that their relevant loss or damage was "reasonably foreseeable by them", and enough to discharge, once and for all, Mr and Mrs Burge's duty to mitigate – even though, as the council had contended and the Tribunal expressly accepted (in paragraph 45), the "foundations [of the conservatory] were too shallow, and … the builders should have dug them deeper". The Tribunal does not seem to have asked itself whether, in the particular circumstances of this case, both as they were in 2003 and also subsequently, Mr and Mrs Burge took such steps as a reasonable property owner would have taken to ensure that the conservatory their contractors built for them was, and remained, capable of withstanding the effects of tree roots. The answer to that question, on the evidence, might have been "Yes". But the question had to be addressed, and in my view it was not.
52. This too, it seems to me, was an error of substance in the Tribunal's decision, not merely a deficiency in its reasons. But even if it were only the latter, it would still have been a material error in the Tribunal's treatment of the decisive issue before it.
53. Both in combination and also individually, the three defects to which I have referred are enough, in my view, to render the Tribunal's decision invalid.
54. In reaching this conclusion, I should add, there is no need for us to take the view that Mr and Mrs Burge had "sought from the outset to use the compensatory machinery … to their personal advantage and to the disadvantage of taxpayers generally" – the concept to which the Tribunal referred in paragraph 48 of its decision.

Did the Tribunal fail to give effect to the purpose of the statutory scheme (ground 1(a))?

55. Mr Choongh submitted that the statutory scheme comprising section 203 of the 1990 Act, like any other legislative scheme, must be construed to give proper effect to its policy and objectives (see the speech of Lord Reid in Padfield and others v Minister of Agriculture, Fisheries and Food [1968] AC 997, at p.1030B-D). The policy and objective underlying section 203, and reflected in article 9 of the TPO, was to provide fair compensation to those who suffer loss as a consequence of consent being refused for the felling of a TPO-protected tree, subject to the exceptions to that entitlement under article 9(4). It was not to compensate for loss resulting from the faulty construction of a building – for example, its construction otherwise than in accordance with industry standards. It would, said Mr Choongh, subvert the policy and objective of these provisions to apply them in such a way as to impose on the public purse the burden of compensating property owners, or their insurers, in circumstances of that kind. The law provides a remedy for a property owner who suffers loss because his building has been negligently constructed. That remedy is a claim in negligence against the builder.
56. Mr Evans-Tovey submitted that, in principle, there was no reason why compensation should not be payable under the statutory scheme in a case where a building was constructed prior to the making and confirmation of a tree preservation order, so that the property owner could not reasonably have been expected to foresee loss or damage arising from a future refusal of consent to fell, or to have taken any steps to avert or mitigate such loss. This case was not one of those in which the building that had sustained damage had been constructed after the TPO was already in place. The purpose of section 203 of the 1990 Act, said Mr Evans-Tovey, was to provide compensation for damage caused by the retention of a tree protected by a tree preservation order. In the statutory provisions for compensation there was no exception for loss or damage sustained by buildings that had been defectively constructed. And that was not the purpose, or effect, of article 9(4)(c) of the TPO. Had the legislature intended to introduce such an exception into the statutory scheme, it could readily have done so. Mr Evans-Tovey relied on the observation of Mr Roger Toulson Q.C. in Paterson v Humberside County Council (at p.68) that "… the fact that the property had shallow foundations and was therefore more susceptible to damage from soil shrinkage caused by invasion of tree roots is no more relevant to liability than the fact that a plaintiff has a thin skull", and that "[the] roots take their victim as they find it". Nor does the statutory scheme exclude a property owner's right to compensation in circumstances where he might also have a claim in negligence against a builder. Had Parliament intended to protect the public purse in that way, again it could have done so.
57. I doubt that this second issue in the appeal adds anything of real significance to the first. If the Tribunal erred in the respects to which I have referred in my conclusions on the first issue, it would, to that extent, have failed to give effect to the object and purpose of the statutory scheme and the provisions in article 9 of the TPO. So I think we can decide the appeal on the very specific basis that I have already indicated.
58. But I would add three general observations about the statutory scheme, which, in part, reflect the submissions made on either side in respect of this issue. First, the statutory scheme and the provisions of article 9 of the TPO do not, in principle, prevent an award of compensation being made to a claimant who may also have a claim in negligence against a contractor responsible for the defective construction of a building, such as by constructing it on inadequate foundations. An award of compensation in those circumstances is not necessarily inimical to the statutory scheme. Secondly, however, the fact that the building that has sustained loss or damage for which compensation is claimed under the statutory scheme was erected before the making and confirmation of the tree preservation order does not, in principle, prevent the Tribunal from finding that the claimant has, nevertheless, failed to discharge the duty to mitigate his loss under article 9(4)(c). That, as I have said, will always depend on the particular facts of the particular case. And thirdly, whilst the operation of the statutory scheme must always be faithful to its relevant provisions and the relevant provisions of the tree preservation order in question, neither of those two observations should be regarded as incompatible with any corresponding principles in the law of nuisance.

Conclusion

59. For the reasons I have given, I would allow the appeal. I acknowledge that, on reconsideration, the decision may still be the same. But the errors I have discerned in the Tribunal's approach make it necessary, in my view, for the claim to be determined afresh. It will, of course, be for the Tribunal to decide whether any further evidence ought now to be admitted.

Lord Justice Irwin

60. I agree.