England and Wales High Court (Administrative Court) Decisions

IN THE HIGH COURT OF JUSTICE
QUEEN'S BENCH DIVISION
PLANNING COURT

		Royal Courts of Justice Strand, London, WC2A 2LL
		13 July 2017

The Deputy Judge (Neil Cameron QC):

Introduction

1. This is an application made by the Claimant local planning authority for an order pursuant to section 288 of the Town and Country Planning Act 1990 ("TCPA 1990") to quash a decision of 17th January 2017 of an inspector appointed by the Secretary of State for Communities and Local Government. By that decision, the inspector allowed the Second Defendant's appeal against the failure by the Claimant to determine within the prescribed period his application for planning permission to develop land at 67, Clarendon Road, London W11 4JE ("the Site") by amalgamation of four existing flats to form a single family dwelling and associated internal alterations.
2. By an order dated 21^st March 2017 Lang J granted the Claimant permission to make this application.
3. In the statement of facts and grounds the Claimant relies upon two grounds of claim:

i) The inspector made a mistake of fact when calculating housing land supply as he deducted vacant units returning to use from the requirement whilst including those units in the supply.

ii) The inspector made a mistake of fact by stating that the housing land supply would be boosted further by recent deliverable planning permissions when those planning permissions were already accounted for in the calculated supply.

4. The First Defendant, the Secretary of State, concedes that the decision should be quashed on the first ground of claim.
5. The Second Defendant contests the claim.

The Background Facts

6. By an application dated 4^th March 2016 the Second Defendant applied to the Claimant for planning permission to develop the Site by "Amalgamation of existing four flats to form a single family dwelling and associated internal alterations".
7. A report was prepared for the meeting of the Claimant's Planning Applications Committee which met on 21^st June 2016. In that report the Claimant's Executive Director of Planning and Borough Development recommended that the Second Defendant's planning application be refused. The report was withdrawn from consideration by the committee in order to allow consideration to be given to the judgment in R (on the application of the Royal Borough of Kensington and Chelsea) v. Secretary of State for Communities and Local Government and David Reis and Gianna Tong [2016] EWHC 1785 (Admin).
8. On the 28^th July 2016 the Second Defendant appealed against the Claimant's failure to determine the application for planning permission within the prescribed period.
9. The appeal was determined under the hearing procedure.
10. The Second Defendant's Statement of Case submitted in support of his appeal stated, at paragraph 7.38:

"7.38 It is also noted that policy CH1 which relates to Housing Targets refers specifically to the Council having sufficient housing sites allocated to ensure the housing targets are met. Whilst the targets set out are not up to date and have been amended by the London Plan, the wording relates to having sufficient housing sites. As stated in the officer's report to committee the current supply from deliverable sites during this period is estimated to be 4,416 dwellings. The 2014/2015 Authority Monitoring Report shows that the Borough's five year housing supply requirement (1st April 2015 to 31st March 2020) is 4,398. The current supply therefore exceeds the requirement. The Council state that it is anticipated that the supply over the five year period will be reduced by approximately 50 units per annum over the five year period through amalgamation, and state that this reduction in supply will result in the borough being unable to meet its supply targets. No evidence is provided to demonstrate this and no information regarding additional units in small sites being provided is given. It is therefore considered to be premature to make an assessment of the supply without the relevant figures being provided. The proposed loss in this individual case is 3 units which would not have an impact on the supply of housing as required as part of policies CH1 of the CLP and policy 3.3 of the London Plan."

11. The Claimant's Written Statement also addressed housing land supply, stating, at paragraph 2.36:

"The appellants confuse existing housing provision with housing need. In paragraph 7.32 of their Statement of Case they quote the existing housing figures from the SHMA. However, the material consideration is the future dwelling size needs for the borough listed in the table within paragraph 2.19 above which demonstrates that an increase in one and two bedroom units is required. Whilst there is also a need for more family units this should not result in a net reduction of smaller units, particularly due to the greater proportional impact on numbers which would result from the loss of three units. As an aside it should be noted that appellant's reasoning also applies to the provision of larger units. They cite the SHMA text which notes that "there is relative to other inner London boroughs, a reasonable proportion of very large houses (11%)." Using the appellant's flawed logic this would imply that the existing ample provision of homes of equivalent size to the appeal scheme means there is no further need to provide such units."

12. The inspector's decision was communicated by a decision letter dated 17^th January 2017.
13. At paragraph 6 of the decision letter, the inspector identified the main issue as being:

"6. The effect of the proposed development on the supply and choice of housing within Kensington and Chelsea."

14. At paragraph 11 of the decision letter, the inspector found that the proposed development would not breach policy CH2 in the Consolidated Local Plan. In relation to policy CH3 in the Consolidated Local Plan he concluded (at paragraph 13 of the decision letter):

"13. Paragraph 35.3.34 preceding policy CH3 refers to protecting residential units in most cases. It also states that there are a limited number of situations in which losses will be permitted in order to meet the various policy objectives of the plan. Policy CH3 itself is not expressed in the same terms. However paragraph 35.3.34 clearly sets the context for the way in which the policy should be read. I consider that taking these parts of the CLP together, the proposal would not comply with paragraph 'a' of CLP policy CH3 and none of the exceptions at sub-paragraphs 'a i' to 'a v' apply. The conflict with CLP CH3 will need therefore to be weighed in the overall planning balance. In doing so I will consider the approach of the CLP which at paragraph 35.3.18 accepts that a balance needs to be struck between the loss of residential units and the need for larger family dwellings."

15. The inspector held, at paragraph 17 of the decision letter, that the loss of existing small self-contained flats would cause the proposal not to comply with saved Unitary Development Plan policy H17.
16. The inspector considered Housing Needs and Supply at paragraphs 26 to 35 of the decision letter. Paragraphs 26 to 33 of the decision letter state:

"26. The adopted target within the CLP of 350 net additional dwellings per year has been updated. The current LP has subsequently set the target as 733 dwellings per year which is applicable. With a 20% buffer for persistent under delivery as required by the Framework the 5 year supply requirement is 4,398 dwellings between 1 April 2015 to 31 March 2020.

27. The Council's 2014/15 Authority Monitoring Report (AMR) figure for deliverable sites is 4,416 dwellings. This therefore indicates that there is likely to be an over-supply of 18 dwellings over that period.

28. The Council has drawn attention to a problem in the number of net completions of sites with permission. However, footnote 11 on page 12 of the Framework states that sites with planning permission should be considered deliverable until permission expires unless there is clear evidence that the schemes will not be implemented within 5 years. The Council's evidence shows that between 2009/10 and 2014/15 net residential approvals have exceeded the applicable target in all years apart from in 2012/13. I recognise some of the permissions will have expired.

29. There has however been a marked increase in completions over the last year where figures were provided by the Council (2014/15). Completions exceeded the 600 target by 382 homes. In the previous year there was a deficit of 336 units. Over the 2 years the target was therefore exceeded by 46 dwellings. It would not be appropriate to read too much into the data of 1 or 2 years however there should also be an assumption that recent planning permissions will be delivered unless there is evidence to the contrary given the wording of the Framework. I therefore consider that it is reasonable to conclude that there will be at least some further degree of over-supply.

30. A number of vacant units returning back into use may also be a relevant factor. In the Drayton Gardens appeals the Inspector took the view that the effect of the vacant units reduces the new stock housing annual target to 687. The Council does not agree with that approach. They refer to the Planning Practice Guidance relating to updating of evidence on the supply of specific deliverable sites. I agree that up-to-date housing requirements and the deliverability of sites to meet a 5 year supply will have been thoroughly considered and examined within the local plan examination process. That degree of scrutiny cannot be replicated while determining planning applications. However, the number vacant units coming back into use is derived from the LP and the AMR.

31. The logic of taking account of vacant units seems reasonable to me because it reflects the realistic need for housing within the area. This has consequences for how the overall 5 years supply figure should be considered and I return to that below. I cannot go as far as the Inspector did in the Drayton Gardens appeals by increasing the allowance for returning vacancies even further because I do not have the same evidence before me.

32. On the other hand, the Council refers to the numbers of residential losses being around 50 per year due to amalgamations (409 between 2009/10 and 2014/15). This figure is derived from monitoring planning applications and applications for LDCs relating to amalgamations. The Council accepts that in relation to LDCs in particular this does not give the whole picture. They also stated at the hearing that the figure has not involved monitoring of implemented certificates or planning permissions or reference to Council tax records. This also provides no indication of future likely trends given the change in the way these matters have been viewed since 2014 and that the Council now exert control over such proposals. Paragraph 35.3.6 of the emerging partial review of the CLP has referred to similar figures and they may at some point, following scrutiny through the process, attain greater acceptance or may be changed. At the moment I can give them little weight as there is some doubt about whether the figures provide a reliable demonstration of how many dwellings have been or will be lost.

33. I reach the view that based upon the AMR and LP, it is likely that there will be an over-supply of 18 units over the course of the 5 year period, that it should be boosted further by recent, deliverable approvals as well as additional 'headroom' of around 230 units over the 5 year period due to vacant units returning to use. I accept that a number of further applications for the amalgamation of units may also come forward and decisions should be reached on the evidence available at that time. I need to make this decision based upon the merits as they exist at the moment."

17. The inspector's conclusions are set out at paragraphs 36 to 39 of the decision letter:

"36. The proposal would not comply with CLP policy CH3 and LP policy 3.14B. There is further conflict with UDP policy H17 as small units would be lost. However from the available information it appears at this time that the Council is likely to meet and exceed its 5 year housing supply requirements. The loss of 3 residential units would not undermine the aims of CLP policy CH1.

37. The latest SHMA indicates that there is a substantial need for 3 and 4 bedroom dwellings and that the current mix of house types is weighted far more in favour of 1 and 2 bedroom homes. The provision for smaller units has seen a significant increase since 2001 (according to the SHMA Area Profile). The proportion of 3 and 4 bed dwellings likely to be required in future is not as great as 80% as estimated within the CLP at paragraph 35.3.10. However there will be a significant on-going need for the type of accommodation being proposed within the Council's area.

38. The SHMA indicates that the need for smaller units is likely to come forward on new developments. The small units that would be lost through this proposal are more affordable than the proposed larger unit would be. However the Council does not suggest that they would be considered as truly affordable for residents unable to compete in the housing market.

39. The Framework at paragraph 50 requires a mix of housing to be planned for based on current and future demographic trends. I give substantial weight to the benefits of helping to meet a need of a particular group by creating a good sized, family dwelling. CLP paragraph 35.3.18 acknowledges that it is necessary to strike a balance between the loss of residential units and the need for larger family dwellings. It would be inconsistent with the Framework to rigidly apply UDP policy H17 which seeks to meet needs that could be outdated and I therefore only give limited weight to the conflict with that policy. The proposal also conflicts with CLP policy CH3 and LP Policy 3.14B. However I consider that the substantial weight that I give to the benefits along with the compliance with LP policy 3.14A would outweigh the conflicts with those development plan policies. I have reached this view also given the limited net loss of units and in the context of the evidence indicating that the Council is on target to meet its 5 years housing supply requirement. Therefore, in relation to the main issue, the proposed development would have an acceptable effect upon the supply and choice of housing within Kensington and Chelsea."

The Legal Framework

18. Section 288(1) of the TCPA 1990 provides:

"288.— Proceedings for questioning the validity of other orders, decisions and directions.

(1) If any person—

…

(b) is aggrieved by any action on the part of the Secretary of State or the Welsh Ministers to which this section applies and wishes to question the validity of that action on the grounds—

(i) that the action is not within the powers of this Act, or

(ii) that any of the relevant requirements have not been complied with in relation to that action,

he may make an application to the High Court under this section."

19. The powers of the court when hearing a section 288 application are identified at section 288(5):

"(5) On any application under this section the High Court—

(a) ……….

(b) if satisfied that any such order or action is not within the powers of this Act, or that the interests of the applicant have been substantially prejudiced by a failure to comply with any of the relevant requirements in relation to it, may quash that order or action."

20. The principles to be applied when considering an application made under section 288 of TCPA 1990 are well established, and were summarised by Lindblom J (as he then was) in Bloor Homes East Midlands Limited v Secretary of State for Communities and Local Government [2014] EWHC 754 (Admin) at paragraph 19:

"19 The relevant law is not controversial. It comprises seven familiar principles:

(1) Decisions of the Secretary of State and his inspectors in appeals against the refusal of planning permission are to be construed in a reasonably flexible way. Decision letters are written principally for parties who know what the issues between them are and what evidence and argument has been deployed on those issues. An inspector does not need to "rehearse every argument relating to each matter in every paragraph" (see the judgment of Forbes J. in Seddon Properties v Secretary of State for the Environment (1981) 42 P. & C.R. 26, at p.28).

(2) The reasons for an appeal decision must be intelligible and adequate, enabling one to understand why the appeal was decided as it was and what conclusions were reached on the "principal important controversial issues". An inspector's reasoning must not give rise to a substantial doubt as to whether he went wrong in law, for example by misunderstanding a relevant policy or by failing to reach a rational decision on relevant grounds. But the reasons need refer only to the main issues in the dispute, not to every material consideration (see the speech of Lord Brown of Eaton-under-Heywood in South Bucks District Council and another v Porter (No. 2) [2004] 1 WLR 1953, at p.1964B-G).

(3) The weight to be attached to any material consideration and all matters of planning judgment are within the exclusive jurisdiction of the decision-maker. They are not for the court. A local planning authority determining an application for planning permission is free, "provided that it does not lapse into Wednesbury irrationality" to give material considerations "whatever weight [it] thinks fit or no weight at all" (see the speech of Lord Hoffmann in Tesco Stores Limited v Secretary of State for the Environment [1995] 1 WLR 759, at p.780F-H). And, essentially for that reason, an application under section 288 of the 1990 Act does not afford an opportunity for a review of the planning merits of an inspector's decision (see the judgment of Sullivan J., as he then was, in Newsmith v Secretary of State for [2001] EWHC Admin 74, at paragraph 6).

(4) Planning policies are not statutory or contractual provisions and should not be construed as if they were. The proper interpretation of planning policy is ultimately a matter of law for the court. The application of relevant policy is for the decision-maker. But statements of policy are to be interpreted objectively by the court in accordance with the language used and in its proper context. A failure properly to understand and apply relevant policy will constitute a failure to have regard to a material consideration, or will amount to having regard to an immaterial consideration (see the judgment of Lord Reed in Tesco Stores v Dundee City Council [2012] PTSR 983, at paragraphs 17 to 22).

(5) When it is suggested that an inspector has failed to grasp a relevant policy one must look at what he thought the important planning issues were and decide whether it appears from the way he dealt with them that he must have misunderstood the policy in question (see the judgment of Hoffmann L.J., as he then was, South Somerset District Council v The Secretary of State for the Environment (1993) 66 P. & C.R. 80, at p.83E-H).

(6) Because it is reasonable to assume that national planning policy is familiar to the Secretary of State and his inspectors, the fact that a particular policy is not mentioned in the decision letter does not necessarily mean that it has been ignored (see, for example, the judgment of Lang J. in Sea Land Power & Energy Limited v Secretary of State for Communities and Local Government [2012] EWHC 1419 (QB), at paragraph 58).

(7) Consistency in decision-making is important both to developers and local planning authorities, because it serves to maintain public confidence in the operation of the development control system. But it is not a principle of law that like cases must always be decided alike. An inspector must exercise his own judgment on this question, if it arises (see, for example, the judgment of Pill L.J. Fox Strategic Land and Property Ltd. v Secretary of State for Communities and Local Government [2013] 1 P. & C.R. 6, at paragraphs 12 to 14, citing the judgment of Mann L.J. in North Wiltshire District Council v Secretary of State for the Environment [1992] 65 P. & C.R. 137, at p.145)."

21. The principles relating to mistake of fact were considered by Carnwath LJ (as he then was) when giving the judgment of the court in E v. Secretary of State for the Home Department [2004] EWCA Civ 49:

"61. As the passage cited by Lord Slynn shows, the editors of the current edition of De Smith (unlike Wade and Forsyth) are somewhat tentative as to whether this is a separate ground of review:

"The taking into account of a mistaken fact can just as easily be absorbed into a traditional legal ground of review by referring to the taking into account of an irrelevant consideration or the failure to provide reasons that are adequate or intelligible or the failure to base the decision upon any evidence." (para 5/-094).

62. We are doubtful, however, whether those traditional grounds provide an adequate explanation of the cases. We take them in turn:

i) Failure to take account of a material consideration is only a ground for setting aside a decision, if the statute expressly or impliedly requires it to be taken into account ... Re Findlay [1985] AC 318, 333–4, per Lord Scarman). That may be an accurate way of characterising some mistakes; for example, a mistake about the development plan allocation, where there is a specific statutory requirement to take the development plan into account (as in Hollis). But it is difficult to give such status to other mistakes which cause unfairness; for example whether a building can be seen (Jagendorff), or whether the authority has carried out a particular form of study (Simplex).

ii) Reasons are no less "adequate and intelligible", because they reveal that the decision-maker fell into error; indeed that is one of the purposes of requiring reasons.

iii) Finally, it may impossible, or at least artificial, to say that there was a failure to base the decision on "any evidence", or even that it had "no justifiable basis" (in the words of Lord Nolan: see above). In most of these cases there is some evidential basis for the decision, even if part of the reasoning is flawed by mistake or misunderstanding.

63. In our view, the CICB case points the way to a separate ground of review, based on the principle of fairness. It is true that Lord Slynn distinguished between "ignorance of fact" and "unfairness" as grounds of review. However, we doubt if there is a real distinction. The decision turned, not on issues of fault or lack of fault on either side; it was sufficient that "objectively" there was unfairness. On analysis, the "unfairness" arose from the combination of five factors:

i) An erroneous impression created by a mistake as to, or ignorance of, a relevant fact (the availability of reliable evidence to support her case);

ii) The fact was "established", in the sense that, if attention had been drawn to the point, the correct position could have been shown by objective and uncontentious evidence;

iii) The claimant could not fairly be held responsible for the error;

iv) Although there was no duty on the Board itself, or the police, to do the claimant's work of proving her case, all the participants had a shared interest in co-operating to achieve the correct result;

v) The mistaken impression played a material part in the reasoning

…………………..

66. In our view, the time has now come to accept that a mistake of fact giving rise to unfairness is a separate head of challenge in an appeal on a point of law, at least in those statutory contexts where the parties share an interest in co-operating to achieve the correct result. Asylum law is undoubtedly such an area. Without seeking to lay down a precise code, the ordinary requirements for a finding of unfairness are apparent from the above analysis of CICB. First, there must have been a mistake as to an existing fact, including a mistake as to the availability of evidence on a particular matter. Secondly, the fact or evidence must have been "established", in the sense that it was uncontentious and objectively verifiable. Thirdly, the appellant (or his advisers) must not been have been responsible for the mistake. Fourthly, the mistake must have played a material (not necessarily decisive) part in the Tribunal's reasoning."

22. The principles established in E v. Secretary of State for the Home Department are, in part derived from (E v. Secretary of State at paragraphs 58 and 59), and have been applied in planning cases including R(on the application of Patel) v. Secretary of State for Communities and Local Government [2016] EWHC 3354 (Admin) at paragraph 22.

Ground 1

23. The Claimant and the Second Defendant are agreed that the inspector erred when at paragraph 33 of the decision letter he referred to additional 'headroom' of around 230 units, being the excess of housing land supply over the requirement arising due to vacant units returning to use. The error arose because vacant units returning to use were deducted from the land supply requirement but included in the supply.

The Claimant's Submissions

24. Mr Straker QC emphasised that this ground of claim was based upon section 288(1)(b)(i) of the TCPA 1990, namely that the action of the Secretary of State was not within the powers of the Act. He submitted that by making the error, in relation to the housing land supply figures, the inspector had either taken into account an immaterial consideration or made a mistake of fact. He further submitted that the error played a material part in the inspector's reasoning.

The Second Defendant's Submissions

25. Mr Lockhart-Mummery QC submitted that whether the ground of claim relied upon was categorised as taking into account an immaterial consideration or a mistake of fact giving rise to unfairness, the essential question to be considered is whether the error played a material (not necessarily decisive) part in the inspector's reasoning.
26. Mr Lockhart-Mummery QC submitted that, the overriding principle to be derived from E v. Secretary of State for the Home Department is that a decision should not stand if a mistake of fact gives rise to unfairness. He submitted that there was no unfairness as:

i) The key reasons for the decision as expressed at paragraphs 36-39 of the decision letter, were qualitative, in that as a matter of planning judgment the inspector gave substantial weight to the benefits of the proposal which he found outweighed the conflicts with development plan policies.

ii) The decision of the planning inspector relates to a finite dispute not to the exercise of a continuing responsibility as referred to in paragraph 43 in E v. Secretary of State for the Home Department. It is a 'one off' decision.

iii) The inspector noted (at paragraph 25 of the decision letter) that draft policies in the Royal Borough of Kensington and Chelsea Consolidated Local Plan review allow for some amalgamation of residential units.

iv) There is no claim by the Claimant that the First Defendant's decision is causing prejudice to them in determining current pending planning applications.

27. Mr Lockhart-Mummery QC submitted that it would be inappropriate to find that the conclusions at paragraphs 36 to 39 in the decision letter were 'legally tainted' by the error in paragraph 33.

Conclusion

28. There is no dispute between the Claimant and the Second Defendant that, in deducting vacant units from the housing land requirement, the inspector made a mistake of fact, and that the first three of the four criteria identified by Carnwath LJ in E v. Secretary of State for the Home Department are satisfied. In my judgment, whether categorised as taking into account an immaterial consideration or as a mistake of fact giving rise to unfairness, the dispute turns on whether the mistake played a material (not necessarily decisive) part in the inspector's reasoning. The determination of that issue turns on the wording of the decision letter itself and raises no question of general principle or of general application.
29. Decision letters are to be construed in a reasonably flexible way. They are not to be construed as if they were a statute or contract.
30. The inspector, at paragraph 36 of the decision letter, found a conflict with relevant development plan policies and then records "from the available information it appears at this time that the Council is likely to meet and exceed its 5 year housing supply requirements". At paragraph 39 of the decision letter the inspector states that he has reached his view that the benefits of the proposal outweigh the conflicts with the development plan policies "… also given the limited net loss of units in the context of the evidence indicating that the Council is on target to meet its 5 years housing supply requirement." It is clear from the conclusions that the finding that the Council is likely to meet and exceed its 5 year housing land supply requirements was a material factor in the inspector's decision making process.
31. Mr Lockhart-Mummery QC submitted that those conclusions could have been reached on the basis of the correct housing land supply figures and that as a result the conclusions were entirely proper and the finding that there was a 'headroom' of 230 units was not material in the dominant reasoning. In reply Mr Straker QC submitted that the question was not whether the error played a part in the dominant reasoning, but whether the error played a material (not necessarily decisive) part in the reasoning.
32. The issue to be determined is not whether the mistake played a decisive part in the inspector's reasoning or whether it played a part in the dominant reasoning, but whether it played a material part in the reasoning. An inspector's decision letter must be read as a whole and read fairly. In my judgment it is clear that the mistake of fact played a material part in the inspector's reasoning and decision and as a result led to unfairness. The inspector made a finding on the housing land supply issue at paragraph 33 of the decision letter. At paragraph 36 he refers to the fact that "from the available information" it appears that the Council is likely to meet and exceed its 5 year housing supply requirements. The inspector does not limit the evidential basis for his conclusion to the figures in the Monitoring Report but refers to the available information. That information must include that which he has summarised at paragraph 33. Similarly at paragraph 39 the inspector does not refer to the Monitoring Report but to "the evidence" indicating that the Council is on target to meet its 5 year housing supply requirement. The evidence to which the inspector refers includes that which he refers to at paragraph 33 of the decision letter.
33. For those reasons I find that the ground of challenge is made out.

Ground 2

34. Mr Straker QC submitted that the inspector erred when, at paragraph 29 of the decision letter, he came to the conclusion that there would be at least some further degree of over-supply on the ground that there should be an assumption that recent planning permissions will be delivered. Mr Straker QC submitted that the figure for housing land supply in the Claimant's Monitoring Report already took account of the fact that planning permissions had been granted and therefore the inspector had double-counted those planning permissions when assessing supply. He submits that the error played a material part in the inspector's decision making process as, at paragraph 33 of the decision letter, he states that supply should be boosted by recent deliverable approvals "as well as" additional 'headroom' of 230 units over the five year period due to vacant units returning to use.
35. Mr Lockhart-Mummery QC did not accept that the inspector fell into a factual error. He submitted that the last sentence of paragraph 29 of the decision letter was justified and conservative.

Conclusions

36. In the last sentence of paragraph 29 of the decision letter the inspector did not seek to quantify the further degree of over-supply but makes a planning judgement that it is reasonable to conclude that there will be at least some further degree of over-supply.
37. The inspector did not, as contended on behalf of the Claimant, add on a figure for recent planning permissions, he made a qualitative judgement that there would be at least some further degree of over-supply.
38. That judgement was based upon the evidence before the inspector, including the information contained in the Monitoring Report (at Table 10.1) on the relationship between net residential approvals and net residential completions, and to which he refers at paragraph 29 of the decision letter.
39. In my judgment it was open to the inspector, in the exercise of his planning judgement, to make the finding that he did, and that there was no mistake of fact.
40. For those reasons I reject Ground 2.

Discretion

41. Mr Lockhart-Mummery submitted that the court has a wide discretion not limited to the issue identified in Simplex G.E. Holdings v. Secretary of State for the Environment (1989) 57 P & CR 306 (at pages 327 and 329). He placed particular emphasis on the fact that this decision is a 'one off' decision, and that his clients wish to be able to create and live in a family home.
42. Mr Straker QC submitted that, when considering the exercise of the court's discretion regard should be had to the fact that, on 22^nd February 2017, after the date of the decision letter, it had been discovered that there was an error in the calculation of the five year housing land supply figure in chapter 10 of the Claimant's 2015 Monitoring Report, and that the supply of deliverable sites for the period 2015 to 2020 is 3,670, not 4,416 as stated in the 2015 Monitoring Report. If the supply figure is 3,670 it is insufficient to meet the requirement, of 4,398.
43. Mr Lockhart-Mummery QC submitted that the mistake in the Monitoring Report relied upon by the Claimant is irrelevant.
44. Although the mistake in the Monitoring Report is relevant to the exercise of discretion, I accept the substance of Mr Lockhart-Mummery QC's submission that, given the nature of the mistake and that it was discovered after the inspector had made his decision, it should have little bearing on the exercise of the court's discretion.
45. The decision can still stand if the court is of the view that the inspector would have reached the same conclusion if the error had not been made. For the reasons I have given the error was material, and I cannot say that the decision would have been the same if the error had not been made, and therefore I do not exercise my discretion not to quash.

Conclusion

46. For the reasons I have given I allow the application and quash the Secretary of State's decision.