Home > News > Court of Appeal rules on application of Natural England’s nutrient neutrality guidance

R (Wyatt) v Fareham BC & Natural England [2022] EWCA Civ 983

The Court of Appeal (Sir Keith Lindblom SPT, Singh and Males LJJ) today dismissed an appeal against the decision of Jay J [2021] EWHC 1434 (Admin) and has rejected the claim for judicial review of Fareham’s decision to grant permission for new housing applying Natural England’s nutrient neutrality advice for the Solent (now replaced by guidance issued earlier this year). The Court rejected criticisms of the Natural England guidance and the majority rejected criticisms of the Council’s application of it. Males LJ reached the same conclusion but by the application of the high threshold of Wednesbury. The Court also rejected a challenge based on the interpretation of plan policy and the application of s. 38(6) of the Planning and Compulsory Purchase Act 2004.\

The Senior President (Singh LJ agreeing) began by summarising the principles relating to habitats assessments at [9]:

“9. There is a wealth of case law relevant to article 6(3) and regulation 63, both in the Court of Justice of the European Union (“the CJEU”) and in the domestic courts. Some basic points emerge:

(1) The duty imposed by article 6(3) of the Habitats Directive and regulation 63 of the Habitats Regulations rests with competent authorities, not with the courts. Whether a plan or project will adversely affect the integrity of a European protected site under regulation 63(5) is always a matter of judgment for the competent authority itself (see the judgment of the CJEU in Holohan v An Bord Pleanála (Case C-461/17) [2019] PTSR 1054, at paragraph 44). That is an evaluative judgment, which the court is neither entitled nor equipped to make for itself (see the judgment of Lord Carnwath in R. (on the application of Champion) v North Norfolk District Council [2015] UKSC 52; [2015] 1 W.L.R. 3170, at paragraph 41, and the judgment of Lord Justice Sales, as he then was, in Smyth v Secretary of State for Communities and Local Government [2015] EWCA Civ 174; [2015] PTSR 1417, at paragraph 83). In a legal challenge to a competent authority’s decision, the role of the court is not to undertake its own assessment, but to review the performance by the authority of its duty under regulation 63. The court’s function is supervisory only. This has been emphasised often in the domestic cases (see, for example, the recent first instance judgment in Compton Parish Council v Guildford Borough Council [2020] J.P.L. 661, at paragraph 207).

(2) In Coöperatie Mobilisation for the Environment UA, Vereniging Leefmilieu v College van Gedeputeerde Staten van Limburg (Case C-293/17) [2019] Env. L.R. 27 (“Dutch Nitrogen”), the CJEU said that it is “for the national courts to carry out a thorough and in-depth examination of the scientific soundness of the “appropriate assessment”…” (paragraph 101 of the judgment), which “makes it possible to ensure that there is no reasonable scientific doubt as to the absence of adverse effects of each plan or project on the integrity of the site concerned, which it is for the national court to ascertain” (paragraph 104). The force of these statements is that the court, for its part, must be wholly satisfied in the exercise of its supervisory jurisdiction that the competent authority’s performance of its obligations under article 6(3) was lawful. It must satisfy itself of the lawfulness of the authority’s consideration of the scientific soundness of the appropriate assessment. But there is nothing in the CJEU’s judgment to suggest that it intended to transform the respective roles of the competent authorities and the domestic courts by giving the court the job of undertaking an alternative appropriate assessment of its own.

(3) When reviewing the performance by a competent authority of its duty under regulation 63, the court will apply ordinary public law principles, conscious of the nature of the subject-matter and the expertise of the competent authority itself. If the competent authority has properly understood its duty under regulation 63, the court will intervene only if there is some Wednesbury error in the performance of that duty (see the judgment of Sales L.J. in Smyth, at paragraph 80, and the judgment of this court in Plan B Earth v Secretary of State for Transport [2020] PTSR 1446, at paragraphs 68 and 75 to 79, which were not doubted by the Supreme Court in the same proceedings ([2021] PTSR 190)). When exercising its supervisory function, the court will apply the normal Wednesbury standard, not a heightened standard such as “anxious scrutiny” (cf. R. v Ministry of Defence, ex parte Smith [1996] Q.B. 517, and R. (on the application of Mahmood) v Secretary of State for the Home Department [2001] 1 W.L.R. 840). It is well- established that such a heightened standard will apply only where fundamental rights or constitutional principles are at stake (see the judgment of Lord Carnwath in Kennedy v Charity Commission[2014] UKSC 20, at paragraph 245, and the first instance decision in R. (on the application of McMorn) v Natural England [2015] EWHC 3297 (Admin), at paragraphs 204 and 205). Given the demanding requirement inherent in regulation 63(5) – for the competent authority to ascertain that the project “will not adversely affect the integrity of the European site” – the court’s examination of the authority’s performance of its duty will be suitably exacting within the bounds of its jurisdiction. But it should be remembered that the autonomous approach of the domestic courts in judging the lawfulness of such action has been explicitly approved by the CJEU (see the judgment of this court in Plan B Earth, at paragraphs 74, 75 and 137, discussing the CJEU’s decision in Craeynest v Brussels Hoofdstedelijk Gewest (Case C-723/17) [2020] Env. L.R. 4).

(4) A competent authority is entitled, and can be expected, to give significant weight to the advice of an “expert national agency” with relevant expertise in the sphere of nature conservation, such as Natural England (see the judgment of Sales L.J. in Smyth, at paragraph 84, and the first instance judgment in R. (on the application of Preston) v Cumbria County Council [2019] EWHC 1362 (Admin), at paragraph 69). The authority may lawfully disagree with, and depart from, such advice. But if it does, it must have cogent reasons for doing so (see the judgment of Baroness Hale in R. (on the application of Morge) v Hampshire County Council [2011] 1 W.L.R. 268, at paragraph 45, the judgment of Sales L.J. in Smyth, at paragraph 85, and the first instance judgment in R. (on the application of Prideaux) v Buckinghamshire County Council [2013] Env. L.R. 32, at paragraph 116). And the court for its part will give appropriate deference to the views of expert regulatory bodies (see, for example, the judgment of Lord Justice Beatson in R. (on the application of Mott) v Environment Agency [2016] 1 W.L.R. 4338, at paragraphs 69 to 77).

(5) When provided with expert evidence in a claim for judicial review, the court will not substitute its own opinion for that of the expert. As this court emphasised in R. (on the application of BACI Bedfordshire) v Environment Agency [2020] Env L.R. 16, at paragraph 87, “[unless] there is clear evidence revealing a failure of … expertise – for example, some conspicuous factual or scientific error – the court is entitled to conclude there was no such failure”. Experts may be expected to provide enough explanation to enable the court to decide whether the views they have stated are based on a conspicuous error (see the judgment of Sales L.J. in Smyth, at paragraph 83). But the court will bear in mind that decisions which entail “scientific, technical and predictive assessments by those with appropriate expertise” and which are “highly dependent upon the assessment of a wide variety of complex technical matters by those who are expert in such matters and/or who are assigned to the task of assessment (ultimately by Parliament)” should be accorded a substantial margin of appreciation (see the judgment of this court in Plan B Earth, at paragraph 68, and, at first instance in the same case, Spurrier v Secretary of State for Transport [2020] PTSR 240, at paragraphs 176 to 180).

(6) The requirement in the second sentence of article 6(3) of the Habitats Directive and in regulation 63(5) of the Habitats Regulations embodies the “precautionary principle, and makes it possible effectively to prevent adverse effects on the integrity of protected sites as a result of the plans or projects being considered” (see the judgment of the CJEU in Landelijke Vereniging tot Behoud van de Waddenzee v Staatssecretaris Van Landbouw, Natuurbeheer en Visserij (Coöperatieve Producentenorganisatie van de Nederlandse Kokkelvisserij UA intervening) (Case C-127/02)) [2005] 2 C.M.L.R. 31 (“Waddenzee”), at paragraph 58). The “precautionary principle” requires a high standard of investigation (see the judgment in Waddenzee, at paragraphs 44, 58, 59 and 61).

(7) The duty placed on the competent authority by article 6(3) and regulation 63 is to ascertain that there will be no adverse effects on the integrity of the protected site, but that conclusion does not need to be established to the standard of “absolute certainty”. Rather, the competent authority must be “satisfied that there is no reasonable doubt as to the absence of adverse effects on the integrity of the site concerned” (paragraphs 44, 58, 59, and 61 of the CJEU’s judgment and paragraphs 107 and 108 of the Advocate General’s opinion in Waddenzee, and the judgment in Holohan, at paragraphs 33 to 37). In Waddenzee (at paragraph 59), the CJEU emphasised the responsibility of the competent authority, having taken account of the conclusions of the appropriate assessment, to authorise the proposed development “only if [it] has made certain that it will not adversely affect the integrity of that site”. That, it said, “is the case where no reasonable scientific doubt remains as to the absence of such effects”. But as Advocate General Kokott explained in Waddenzee (in paragraphs 102 to 106 of her opinion), a requirement of “absolute certainty” would be “disproportionate”. As she said (at paragraph 107), “the necessary certainty cannot be construed as meaning absolute certainty …”, the conclusion of an appropriate assessment is, “of necessity, subjective in nature”, and “competent authorities can, from their point of view, be certain that there will be no adverse effects even though, from an objective point of view, there is no absolute certainty”. Similar observations appear in the judgment itself (in paragraphs 44, 58, 59 and 61). As the Supreme Court acknowledged in Champion, adopting the approach in Waddenzee, “while a high standard of investigation is demanded, the issue ultimately rests on the judgment of the authority” (see the judgment of Lord Carnwath, at paragraph 41). This approach is, in essence, what the “precautionary principle” requires in the context of article 6(3) of the Habitats Directive and regulation 63 of the Habitats Regulations.

(8) The requirement that there be “no reasonable doubt as to the absence of adverse effects on the integrity of the site concerned” does not mean that the “reasonable worst-case scenario” must always be assessed. In the European Commission guidance document entitled “Communication on the precautionary principle” (2000) it is stated in Annex III that “[when] the available data are inadequate or non-conclusive, a prudent and cautious approach to environmental protection, health or safety could be to opt for the worst-case hypothesis”. That guidance, however, is not law (see Heard v Broadland District Council [2012] Env. L.R. 23, at paragraph 69, and Prideaux, at paragraph 112), nor is it in mandatory terms. What is required in law is a sufficient degree of certainty to ensure that there is “no reasonable doubt” on the relevant question. It may sometimes be useful to consider a “reasonable worst-case scenario” when assessing whether the necessary degree of certainty has been achieved. But whether there are grounds for “reasonable doubt” will always be a matter of judgment in the particular case.

(9) An appropriate assessment must be based on the “best scientific knowledge in the field” (see Holohan, at paragraph 33). Such knowledge must be both up-to-date and not merely an expert’s bare assertion (see the judgment of Sales L.J. in Smyth, at paragraph 83). And the concept of “best scientific knowledge” is not a wholly free-standing requirement, separate from the precautionary principle itself. It is inherent in the precautionary principle, and in the concept of “no reasonable doubt”.

(10) What is required of the competent authority, therefore, is a case-specific assessment in which the applicable science is brought to bear with sufficient rigour on the implications of the project for the protected site concerned. If an appropriate assessment is to comply with article 6(3) of the Habitats Directive it “cannot have lacunae and must contain complete, precise and definitive findings and conclusions capable of removing all reasonable scientific doubt as to the effects of the works proposed on the protected site concerned” (see the judgment of the CJEU in Sweetman v An Bord Pleanála (Case C-258/11) [2014] PTSR 1092, at paragraph 44, and its judgment in People Over Wind and Sweetman v Coillte Teoranta (Case C-323/17) [2018] PTSR 1668, at paragraph 38).

With regard to NE’s guidance then current the Senior President noted the basis for the advice and that;

“12. In its opening paragraph the technical guidance note recognised that the water environment of the Solent is highly protected for its habitats and species of international importance. It acknowledged that the high levels of nitrogen input to this water environment were causing excessive plant growth – “eutrophication” – in the designated sites, and that the resulting mats of green algae and other impacts on the marine ecology were affecting protected habitats and bird species (paragraph 1.1). It referred to the “potential for future housing developments across the Solent region to exacerbate these impacts [,which] creates a risk to their potential future conservation status”. It introduced “nutrient neutrality” as “a means of ensuring that development does not add to existing nutrient burdens”, adding that “this provides certainty that the whole of the scheme is deliverable in line with the requirements of [the Habitats Regulations]” (paragraph 1.3). It advocated a practical method for calculating how nutrient neutrality could be achieved, based on “best scientific knowledge” but subject to revision as further evidence was obtained (paragraph 1.4)

13. The “best available up-to-date evidence” indicated that some of the protected sites were “widely in unfavourable condition due to existing levels of nutrients” and “at risk from additional nutrient inputs” (paragraph 2.3). In Natural England’s view, there were likely significant effects on several internationally designated sites “due to the increase in wastewater from the new developments coming forward” (paragraph 2.4). Nutrient neutrality would allow local planning authorities to comply with their duties under regulation 63 (paragraph 2.5), and provide “a means of ensuring that development does not add to existing nutrient burdens” (paragraph 2.6)”

He stated that in the subject case:

“23. On 9 June 2020, as statutory consultee under regulation 63(3), Natural England gavE its advice to the council on “nutrient neutrality” for the proposed development. It did so in the light of the council’s “Nitrogen Budget”, dated 11 May 2020. The “Nitrogen Budget” was based on an occupancy rate of 2.4 persons per dwelling and included a precautionary buffer of 20%, both of which were subsequently used in the council’s appropriate assessment. Natural England said that “[provided] the council, as the competent authority, [was] assured and satisfied [that] the site areas [were] correct and that the existing land uses [were] appropriately precautionary”, it raised “no further concerns with regard to the nutrient budget”. Nor did it raise concern about the use of average land use figures for calculating the baseline nitrogen deposition from the site, about the 2.4 occupancy rate, or about the 20% precautionary buffer applied.”

Having set out the competing views in the evidence as to the use of the average occupancy rate of 2.4 per dwelling, the Senior President noted Jay J’s critical view of the use of that rate and the submissions by the Appellant that argued it could never be appropriate to use an average rate and that in cases of uncertainty the reasonable worst case should be assumed. It was also argued by the Appellant that the Dutch Nitrogen case required a more stringent standard of Wednesbury to be applied and that the precautionary elements in NE’s approach including a 20% “buffer” were unlawful. He considered that the Judge had correctly approached the applicable law. In his subsequent consideration of the issues, the Senior President rejected the attacks made against the Natural England guidance.

“52. Whatever the particular circumstances in a given case, the basic duty of the competent authority under regulation 63 is, and remains, to grant planning permission only if satisfied that the proposed development “will not adversely affect the integrity” of the European protected site. The duty of the court is, and remains, to ensure that the authority’s evaluative judgment on that question was lawfully exercised.

53. In doing that, the court must keep in mind the difference between evidence of what was considered by a decision-making authority at the time of its decision and evidence put forward after the event to explain or justify that decision (see R. (on the application of United Trade Action Group Ltd.) v Transport for London [2021] EWCA Civ 1197). It is trite, for example, that later evidence of a decision-maker’s thinking cannot be used to contradict the original reasons given or to provide wholly new reasons (see R. v Westminster City Council, ex parte Ermakov [1996] 2 All E.R. 302, and Inclusion Housing Community Interest Company v Regulator of Social Housing [2020] EWHC 346 (Admin), at paragraph 78). But that has not been done in this case. Ms Potts’ evidence goes no further than to amplify the reasons why Natural England decided to adopt the approach it did, and reached the view it did, at the time of its consultation by the council. The evidence was properly admitted, and the judge was entitled to rely on it as he did.

54. As for the second fundamental error of which the judge is accused, I do not think he adopted too lax an understanding of the precautionary principle, either generally or as it applied in this case, or that he wrongly discounted the concept of the “reasonable worst-case scenario”, contrary to the CJEU’s reasoning inBayer CropScienceand the High Court’s in ex parte Milne. In Bayer CropScience the CJEU cited the European Commission’s guidance, “Communication on the precautionary principle” (2000) Annex III, which advises that in cases of doubt a “worst-case” hypothesis “could” – not must – be assessed (paragraph 114 of the judgment). But it did not treat the guidance as if it had the status of law. It adopted the established approach, consistent with its own judgment in Waddenzee. Nor does the principle referred to in ex parte Milne – that a proposal requiring environmental impact assessment must be sufficiently detailed to allow for proper assessment – bear on the question here, which is whether any uncertainty in the data involved in an appropriate assessment under regulation 63 must always be resolved by using a “reasonable worst-case scenario”. In Waddenzee, as Jay J. said (in paragraph 32 of his judgment), the CJEU accepted that national authorities do not need to be “absolutely certain” that there will not be adverse effects on the integrity of the protected site, but must be “satisfied that there is no reasonable doubt as to the absence of adverse effects”. The judge asked himself “whether “reasonable worst case scenario” is an apt synonym for “precautionary””, but he did not think it was necessary to come to a decisive view on the point (paragraph 47). I do not think he needed to do so. In my view it was legitimate for him to conclude that, at least in this case, the “reasonable worst-case scenario” did not have to be assessed if the precautionary principle was to be satisfied.

55. Turning to ground 1 of the appeal, I do not think there can be any proper challenge in these proceedings to the lawfulness of the advice given by Natural England in its technical guidance note, which seems to have been the real target for much of the argument advanced on behalf of Mr Wyatt.

56. It should be remembered that the technical guidance note is not statute. It does not create some additional legal requirement or test. It is an advisory document, which is neither mandatory in effect nor prescriptive of a single correct procedure to be followed. It contains guidance, whose purpose is to assist competent authorities in performing their functions under the habitats legislation. It does not assert that the approach it suggests is the only means of conducting an appropriate assessment. On the contrary, it expressly acknowledges that this approach is only “a means” or “one way” of undertaking that task (paragraphs 1.3, 2.6 and 4.1).

57. The Supreme Court has recently confirmed that there are only limited grounds on which a policy can be challenged as itself being unlawful (seeR. (on the application of A) v Secretary of State for the Home Department[2021] UKSC 37, and also the recent decision of this court in R. (on the application of Pearce) v The Parole Board [2022] EWCA Civ 4). In R. (on the application of A) Lord Sales and Lord Burnett C.J. stressed that it is “not the role of policy guidance to eliminate all uncertainty regarding its application and all risk of legal errors” (paragraph 34). The appropriate question for the court is this: “does the policy in question authorise or approve unlawful conduct by those to whom it is directed?” (paragraph 38).

58. Where Natural England’s advice on the appropriate occupancy rate is concerned, the answer to that question would clearly be “No”. At the level of generality at which the technical guidance note was suggesting it, the use of an occupancy rate of 2.4 persons per dwelling cannot be said to be unlawful on the ground that it is inconsistent with the “best scientific evidence”. The technical guidance note did not misstate the legal position under regulation 63 (see R. (on the application of A), at paragraphs 46 and 47). It did not “authorise or approve”, let alone prescribe, the use of that occupancy rate by all local planning authorities in every case, regardless of the circumstances. It did not remove or reduce the onus on those authorities to be sure, beyond “all reasonable scientific doubt”, that the integrity of the protected site would not be adversely affected (see paragraphs 1.4, 2.5, 4.6 to 4.9, and 4.18 to 4.19 of the technical guidance note).

59. Nor do I accept the criticism made of the council’s use of an occupancy rate of 2.4 persons per dwelling in the particular circumstances of this case. Although an appropriate assessment must be based on “best scientific knowledge”, the question for the court is not whether each individual figure used in it is intrinsically the “best scientific knowledge” when considered on its own, divorced from the full context in which it is used. As Mr David Elvin Q.C. submitted for Natural England, the court must take a “holistic” view on the question whether the assessment methodology as a whole represents “best scientific knowledge”.

60. When that is done here, it is, I think, plain that the council understood its duty under regulation 63 correctly. This much is clear from the summary of the law which the officer set out in his report (in particular, at paragraph 8.26), and from the equivalent summary in the appropriate assessment itself (in particular, at pp.15 to 19).”

The Senior President held that the Council had consulted NE and had directed itself to the correct requirements and adopted the 2.4 average occupancy rate. He noted the various precautionary elements that went into NE’s advice and the competing expert evidence.

“66. It would not be right for the court to intervene in a case of this kind simply because there is a divergence of expert opinion on some of the figures used in the appropriate assessment. Sometimes, perhaps often, there may not be a consensus of expert opinion. If that is so, there is nothing in law to compel the competent authority in making an appropriate assessment, or the court in reviewing the authority’s decision taken in the light of that appropriate assessment, to default to the most conservative or cautious view propounded.

67. The argument advanced by Mr Jones does not demonstrate that in this case it was inappropriate or unlawful for the council to adopt the occupancy rate of 2.4 persons per dwelling on the ground that it was, in one expert’s view, insufficiently precautionary – or for any other reason. As Mr Elvin submitted, this is a paradigm case of expert witnesses differing on matters of scientific judgment, in which the court would need to be shown some conspicuous error in the competent authority’s own evaluation of the expert advice it received at the time of its decision before that decision could properly be overturned. For the court to upset a decision when it has not been shown that the competent authority’s own exercise of evaluative judgment was so defective as to be Wednesbury unreasonable but where there is disagreement between experts on the correct ingredients of the appropriate assessment, would involve the court stepping beyond its proper supervisory jurisdiction into the realm of the competent authority’s own remit under the habitats legislation.

68. I think Mr Jones’ criticism of the judge’s reasoning on this issue is mistaken. The judge accepted that “[an] occupancy rate of 3 would be the best available scientific evidence for 4-5 bedroom houses in the Fareham region” (paragraph 83). This, however, was not fatal to his essential analysis. Reading the relevant passage of his judgment fairly as a whole, I do not think it can be said that he fell into error. He was recognising the fact that, taken in isolation, an occupancy rate of 3 would generally be appropriate for four and five-bedroom houses in the area. Nowhere did he suggest, however, that in this case the appropriate assessment as a whole was inconsistent with “best scientific knowledge”. He found that the method used in the appropriate assessment, taken in its entirety and thus including the occupancy rate of 2.4, complied with the precautionary principle. He accepted as lawful the council’s conclusion, as a matter of its own judgment, that in the circumstances here an assessment using that occupancy rate was sufficiently precautionary. And in my view he was right to do so.

69. Lastly on this ground, I do not think the judge’s view that Natural England’s technical guidance note would have to be reviewed in the light of his judgment is inconsistent with his view that the approach taken to the occupancy rate in this case was legally defensible. In effect, he was pointing out that the technical guidance note, as drafted, could be liable to misinterpretation or misapplication in other cases, and suggesting that Natural England might describe more clearly the general approach it suggested to this part of the calculation.”

The submissions with regard to what was said in Dutch Nitrogen concerning averages were also rejected:

“72. Those statements about the use of average values in that context must be viewed with care in a case such as this, which is not concerned with “programmatic legislation” but with the individual assessment of the particular effects of a specific project. Nothing said in Dutch Nitrogen implies that in this situation the use of averages is inherently objectionable. It is true that the use of average figures will necessarily involve the exercise of judgment on their validity in the particular context. But this does not mean that using them is, in principle, contrary to the requirement for the necessary degree of certainty, as amplified in Waddenzee. The use of average figures may sometimes be conducive to sufficient certainty, sometimes not. Whether that is so in a particular case will be a matter of judgment for the competent authority.

73. Nothing suggests that in this case either Natural England or the council misunderstood the degree of certainty required by the precautionary principle. Nor is there any evidence to show some justiciable error in the conclusion reached, as a matter of judgment, that the use of average land use figures was, in this case, suitable for the appropriate assessment, and sufficiently robust.”

With regard to the specific challenge to the use of a precautionary 20% buffer:

“75 .. As the judge said (in paragraph 111 of his judgment), the 20% figure is “not derived from any arithmetical calculation or other algorithm”. There is, however, no legal requirement that every element of an appropriate assessment be based on arithmetic or algorithm. That would be a fallacy. If a precautionary buffer is employed, it should be set at a reasonable level, to help achieve adequate certainty that the high threshold in regulation 63 is crossed. But as Mr Mould submitted, to think that reasonable scientific judgments in undertaking an appropriate assessment can only be reached through arithmetical calculation would be to take too narrow a view of rational enquiry. Such judgments can be formed, and sometimes will best be formed, without resort to arithmetic. This will not, in principle, expose the appropriate assessment to the charge that it suffers from “lacunae” or that it lacks “complete, precise and definitive findings”, as required by the CJEU (see the CJEU’s observations in People Over Wind, at paragraph 38).

76. The fact that the 20% precautionary buffer was not the product of arithmetic, but of judgment, does not mean that it lacked an adequate basis. As Ms Potts made clear, the appropriate figure to adopt as a buffer was considered carefully by Natural England, knowing the nature of the risks and uncertainties involved (second witness statement, paragraphs 56 to 64, and third witness statement, paragraphs 19 to 21).

77. Once again, the essence of the complaint is that there is an expert witness – Dr O’Neill – who, in his evidence to the court, has disagreed with a particular figure used in the calculation. That disagreement does not automatically equate to evidence of serious scientific doubt about an appropriate figure for a precautionary buffer. No doubt Dr O’Neill’s evidence shows that, for the reasons he gave, some experts might have adopted a more generous buffer than 20%. This does not mean, however, that the court is bound to find that the buffer actually chosen by Natural England and applied by the council as competent authority was insufficiently precautionary. As Ms Potts’ evidence effectively confirmed, the choice of 20% as the appropriate figure represented the expert regulatory body’s judgment on the level of precautionary buffer consistent with “no reasonable doubt” that the integrity of the protected site would not be adversely affected. It was made with that level of certainty explicitly in mind (third witness statement, paragraph 21). Neither the selection of that figure in Natural England’s technical guidance note nor its use in the appropriate assessment undertaken by the council in this case is open to attack on any legal grounds.”

Males LJ, whilst agreeing with the outcome, approached the issue of the average occupancy differently and was not satisfied that the Council should have applied it or that the 20% buffer was sufficient to deal with it. His view appears more in line with the views of Jay J on this issue. However, he did conclude that the decision was not Wednesbury unreasonable:

“146. Despite this, however, I consider that the use of the national average occupancy rate of 2.4 persons per dwelling did not render the “appropriate assessment” carried out by the Council unlawful. The question for the Council was not whether it had followed precisely the methodology set out in the 2020 Advice, but rather whether it had carried out a sufficient “appropriate assessment” for the purpose of the Habitats Regulations. It was not mandatory to follow precisely the methodology set out in the 2020 Advice and the use of the national average occupancy rate was not questioned by Natural England when consulted about the proposed development. Rather, Natural England stated that it had no concerns. That was a view to which the Council was entitled and required to have regard. It provided a good reason not to follow precisely the methodology set out in the 2020 Advice. In those circumstances we can only interfere with the conclusion of the Council, based on the assessment which it had undertaken, that the proposed development would not contravene Regulation 63 of the Habitats Regulations, if that conclusion was Wednesbury unreasonable. That is a demanding test and I am not persuaded that it is satisfied here.”

Tim Mould QC represented Fareham BC.

David Elvin QC and Luke Wilcox represented Natural England.

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