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Nutrient neutrality, the Solent and new development

The High Court has rejected habitats challenges on nutrient neutrality in the Solent. David Elvin QC explains why.

On Friday 28th May, Mr Justice Jay handed down judgment in two judicial reviews which challenged the approach of Fareham Borough Council in granting permission for two small housing developments to adopting the approach to avoiding adverse effect to the integrity of protected habitats (on the facts of the specific cases) of Natural England’s Advice on Achieving Nutrient Neutrality for New Development in the Solent Region (5th ed. 2020).

Jay J. rejected the grounds that the approach adopted was not sufficiently precautionary having regard to the legal approach to appropriate assessments set out in cases such as R. (Champion) v North Norfolk District Council [2015] 1 WLR 3170, Smyth v Secretary of State for Communities and Local Government [2015] PTSR 1417, Landelijke Vereniging Tot Behoud Van De Waddenzee v Staatsecretaris Van Landbouw (C-127/02) [2005] 2 CMLR 31 and Holohan v An Bord Pleanála (C-461/17) [2019] Env LR 16.

His reasoning on these issues is found in the judgment in R (on the application of Ronald Wyatt, acting in a representative capacity) v. Fareham BC & Others [2021] EWHC 1434 (Admin). The Wyatt case was dismissed but the second case (Save Warsash – [2021] EWHC 1435 (Admin)) succeeded on other grounds. Natural England was an Interested Party in both cases and was represented at the hearing. Permission to appeal was refused by the Judge.

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In approaching the issues in principle Jay J. held:

“28. In view of the parties’ submissions, a number of matters should be highlighted.

29. First of all, it is necessary to underscore the distinction between the degree of rigour the local planning authority must apply to the consideration of its HRAs and the approach this court must take as the reviewing body: the two processes must be kept distinct, pace a number of passages in Mr Jones’ skeleton argument which suggested otherwise. The application of first principles impels this conclusion, but I will be referring below to relevant authority.

30. Secondly, the CJEU has stated on a number of occasions that appropriate assessments must be based on “the best scientific knowledge in the field” (Holohan v An Bord Pleanála (Case C-461/17) [2019] PTSR 1054 at para 33) which is both up-to-date and not based on the bare assertion of an expert (on the latter point, see Smyth v SSCLG [2015] EWCA Civ 174; [2015] PTSR 1417, at para 83).

31. Thirdly, the absence of adverse effects must be established at the point of consent, which in the present context means the date the appropriate assessment is made (Cooperatie Mobilisation for the Environment UA, Vereniging Leefmilieu v College van Gedeputeerde Staten van Limburg (Case C-293/17) [2019] Env LR 27 (the “Dutch Nitrogen case”), at para 94 of the opinion of Advocate General Kokott).

32. Fourthly, a high standard of investigation is demanded in line with the precautionary principle. This has been stated and reiterated in a large number of cases, including in particular Waddenzee (Case C-127/02) [2004] Env LR 14 and the Dutch Nitrogen case. In Waddenzee, Advocate General Kokott stated that the burden on the competent authority was to prove that there would be no adverse effects, not to a standard of absolute certainty but to being “at least satisfied that there is no reasonable doubt as to the absence of adverse effects on the integrity of the site concerned”. A requirement of absolute certainty would be impossible of scientific attainment as well as being disproportionate (see paras 99, 104, 107 and 108). The ECJ accepted the Advocate General’s interpretation of the Habitats Directive in the light of these general principles of EU law, expressing their conclusions in a slightly different way (see paras 44, 58, 59 and 61). At para 58 the CJEU confirmed that the authorisation criterion in the Habitats Directive “integrated” the precautionary principle.

33. In the Dutch Nitrogen case the issue was whether Dutch legislation which set generic threshold values for nitrogen deposition could satisfy the requirement for case-specific assessments. That was not the issue which arises in the instant case, and in my view both Advocate General Kokott and the CJEU did no more than restate well-established principles.”

[The Judge then quoted AG47 and the CJEU paras. 101-104]. He continued:

“34. I read these paragraphs as requiring a case-specific assessment by the competent authority applying rigorous scientific principles to the endeavour. I reiterate that these paragraphs say nothing about the role of the court in exercising its supervisory function.

35. Fifthly, it is clear from the scheme of the Habitats Regulations, the application of common sense and authority that competent authorities must give condign weight to the expert advice of Natural England, and if minded to deviate from that advice furnish cogent reasons for doing so: see, in particular, Baroness Hale JSC in R (Morge) v Hampshire CC [2011] UKSC 2; [2011] 1 WLR 268, at para 45.

36. Sixthly, the judgment whether a proposal will adversely affect the integrity of the protected sites for the purposes of regulation 63(5) of the Habitats Regulations is one for the competent authority. Insofar as case law is required for this proposition, it may be found in R (Champion) v North Norfolk DC [2015] UKSC 52; [2015] 1 WLR 3170, per Lord Carnwath JSC at para 41, referring to Advocate General Kokott in Waddenzee, at para 107. I was also referred to Compton Parish Council v Guildford BC [2019] EWHC 3242 (Admin); [2020] JPL 666, para 207 (per Sir Duncan Ouseley). Advocate General Kokott’s use of the epithet “subjective” requires some care. I consider that all that she meant by that was that reasonable scientific opinion may not converge in complex or disputatious areas.”

In respect of the general approach and methodology in the Advice Note, the Judge held:

“43. In order to ascertain whether nitrogen neutrality is attainable, a nitrogen budget has to be calculated. In very simple terms, this entails a four-stage approach: (1) calculate the total nitrogen in kilogrammes per annum derived from the development that would exit the wastewater treatment works after treatment; (2) adjust the nitrogen load to account for existing nitrogen uses from current land, forming a judgment as to what the load would be if permission were refused; (3) adjust the nitrogen load to account for land uses with the proposed development; and (4) calculate the net change in the nitrogen load that would result from the development.

44. The detailed methodology needs be considered only in three respects (viz. the 2.4 person per dwelling occupancy rate (relevant to item (1) in §43 above); the attribution of the north-western paddock area to “lowland grazing” (relevant to item (2); and the water usage per person of 110 litres/day (relevant to item (1)). Before considering these, I need to set out Natural England’s explanation of the approach to be taken:

“4.6 For those developments that wish to pursue neutrality, Natural England advises that a nitrogen budget is calculated for new developments that have the potential to result in increases of nitrogen entering the international sites. A nutrient budget calculated according to this methodology and demonstrating nutrient neutrality is, in our view, able to provide sufficient and reasonable certainty that the development does not adversely affect the integrity, by means of impacts from nutrients, on the relevant internationally designated sites. This approach must be tested through the ‘appropriate assessment’ stage of the Habitats Regulations Assessment. The information provided by the applicant on the nutrient budget and any mitigation proposed will be used by the local planning authority, as competent authority, to make an appropriate assessment of the implications of the plan or project on the designated sites in question. Further information of this process is available here.

4.7 The nutrient neutrality calculation includes key inputs and assumptions that are based on the best-available scientific evidence and research. It has been developed as a pragmatic tool. However, for each input there is a degree of uncertainty. For example, there is uncertainty associated with predicting occupancy levels and water use for each household in perpetuity. Also, identifying current land / farm types and the associated nutrient inputs is based on best-available evidence, research and professional judgement and is again subject to a degree of uncertainty.

4.8 It is our advice to local planning authorities to take a precautionary approach in line with existing legislation and case-law when addressing uncertainty and calculating nutrient budgets. This should be achieved by ensuring nutrient budget calculations apply precautionary rates to variables and adding a precautionary buffer to the TN calculated for developments. A precautionary approach to the calculations and solutions helps the local planning authority and applicants to demonstrate the certainty needed for their assessments.

4.9 By applying the nutrient neutrality methodology, with the precautionary buffer, to new development, the competent authority may be satisfied that, while margins of error will inevitably vary for each development, this approach will ensure that new development in combination will avoid significant increases of nitrogen load to enter the internationally designated sites.” [emphasis supplied]

45. In my judgment, this advice is impeccable in all material respects. Mr Jones came close to submitting that, because there was scientific uncertainty, no development could properly be permitted because deleterious impacts could not logically be excluded. But that is the whole point of the precautionary principle: the uncertainty is addressed by applying precautionary rates to variables, and in that manner reasonable scientific certainty as to the absence of a predicated adverse outcome will be achieved, the notional burden of proof being on the person advancing the proposal. The application of precautionary values to relevant variables may well have been sufficient, without more; but a further cushion is provided by the application of a precautionary buffer.

46. I invited Mr Elvin in particular to assist me on whether there is any further jurisprudence from international, European or domestic sources as to the meaning of the precautionary principle. I am grateful for his overnight lucubrations although they yielded nothing of additional value. But what I can say – approaching the issue on the basis of both first principles and existing authority – is that paras 4.6-4.9 of the Advice Note represent the implementation par excellence of that principle in their acknowledgment that scientific uncertainty and its concomitant margins of error (which will fluctuate in the light of the unknowns) mandate a precautionary approach to the relevant inputs. Exactly how that applies in practice will be considered subsequently.

47. Mr Elvin invited me not to apply any further gloss on the meaning of “apply precautionary rates to variables”. In particular, he submitted that exegetical formulations such as “reasonable worst case scenario” should be abjured. During the hearing there was some discussion of “bell curves” and normal distributions, and I ventured a slightly flippant analogy of the Medieval architect who might wish to apply a precautionary approach, rather than to take a simple height average, to the construction of doorways to avoid headaches in tall monarchs (such an approach has not to my knowledge been applied). A statistician could no doubt contribute to this discourse. I do have my own views on whether “reasonable worst case scenario” is an apt synonym for “precautionary”, but in the context of judicial review proceedings rather than a witness action in a clinical negligence case (where propositions can be tested by interrogating the expert evidence) I am content to go no further, save to point out that the decision of Sullivan J in R v Rochdale BC, ex parte Tew [2000] Env LR 1, relied on by Mr Jones in this regard, was addressing a rather different question, namely whether there were “likely significant effects” in the context of the obligation to conduct an environmental impact assessment.

48. Mr Elvin also submitted that the precautionary principle embodies both proportionality and a degree of inherent flexibility to reflect the nature of the harmful outcome. Whereas it is true that Advocate General Kokott in Waddenzee referred to proportionality in terms at para 104 of her Opinion, this was in the context of a stream of reasoning which distinguished between absolute and reasonable certainty, the former being unattainable. If all that Mr Elvin was submitting was that in some circumstances it would be close to impossible to obtain precise scientific data and consequently it may be appropriate, as well as proportionate, to draw from generic data and experience in analogous situations, I would agree with him. As for inherent flexibility, I can understand that if the harmful outcome is death or serious disease the scientist would wish to be even more cautious in the application of particular variables, but ultimately the test does not permit of much latitude. Reasonable scientific certainty means what it says, and this is what the Advice Note requires. No value judgment as to the relevant worth of birds and mankind needs to be carried out.”

The Judge considered the three elements under challenge at [49]-[89] and commented with some reservations on the approach adopted by the Council and Natural England’s advice in applying an average occupancy rate of 2.4 based on national and local rates but nonetheless found that the methodology was appropriately precautionary due to the presence of other elements in it, specifically the assumption that 100% of the occupiers of new dwellings were not already living in the catchment and that the water discharge rates were not in direct proportion to the number of bedrooms of the proposed houses (see the judgment at [65], [68] and [86]).

“81. The question is whether my concerns should be elevated to a finding of legal error. The need for judicial deference in a domain of technical and scientific expertise remains. Moreover, Natural England has specifically considered the application of more size-sensitive datasets but rejected the need for it. Only a judge satisfied that all the minutiae and ramifications have been completely absorbed and understood should be prepared to intervene in such circumstances. That is a tall order.

86. Having examined Ms Potts’ evidence with considerable care, yet applying to it the appropriate margin of appreciation in an area which remains technical and complex, Mr Jones has not been able to persuade me on a Wednesbury basis that the appropriate assessment carried out for the purposes of this particular planning application was other than sufficiently precautionary, based as it was on an occupancy value of 2.4. On the facts of this case, I am satisfied that there was an adequate precautionary leeway afforded by the two key factors I have highlighted. That is the expert evidence adduced through Ms Potts, and it is not irrational.

87. The Advice Note will need to be reviewed in the light of this judgment. In particular, I recommend that version 6 of the Advice Note sets out more clearly the circumstances in which bespoke calculations should be used. If Natural England’s belief is that bespoke levels should be reserved for atypical cases, the Advice Note should say so and provide a brief explanation. In any event, if para 4.19 of the Advice Note is being interpreted such that only lower bespoke levels are justified, this imbalance should be rectified. The extent to which it would be appropriate to recommend up to five guideline occupancy rates to reflect what I have said at the end of §80 above is also worthy of further consideration. This judgment should not be interpreted as necessarily giving a clean bill of health to the use of a 2.4 occupancy rate in all circumstances, even those which cannot be described as atypical.”

He rejected the grounds that criticised the Council for relying on the Advice Note and applying it in the context of the specific circumstances of the applications.

David Elvin QC is a barrister at Landmark Chambers. Together with Matthew Henderson, he represented Natural England.

Tim Mould QC, also of Landmark Chambers, represented Fareham BC.

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