Legality of Natural England’s Solent “nutrient neutrality” Habitats Regulations Assessment advice


In the recent High Court judgment of Wyatt, R. (On the Application of) v Fareham Borough Council [2021] EWHC 1434 (Admin) (28 May 2021) relating to Habitats Regulations Assessments ("HRAs"), Mr Justice Jay rejected the challenges made by a local resident objector group to the grant of planning permission for a small housing development by Fareham Borough Council.  The objectors brought forward 8 grounds of challenge in total. This article considers those grounds relating to Natural England’s “nutrient neutrality” advice for local councils in the Solent Region undertaking HRAs.

The nutrient issue: what is it and what does nutrient neutrality mean? 

The importance of achieving nutrient neutrality stems from evidence that large quantities of nitrogen and phosphate nutrients entering water systems cause excessive growth of algae, a process called “eutrophication.” Eutrophication reduces the oxygen content of water which increases the difficulty of survival for aquatic species; subsequently removing a food source for protected species. Many bird species reside in the Solent Region – these are particularly endangered.Nutrient neutrality is a concept promoted by Natural England as “a means of ensuring that development does not add to existing nutrient burdens.”  By adhering to the concept, developers can provide certainty that their scheme is thus “deliverable in line with the requirements of Regulation 63 of the Conservation of Habitats and Species Regulations 2017.” Regulation 63 requires the competent authority, before authorising or undertaking a plan or project likely to have a significant effect on a European site, to “make an appropriate assessment of the implications for that site in view of the site’s conservation objectives,” either alone or in combination with other plans and projects. Crucially, the competent authority may (subject to the HRA derogation tests) only agree to the plan or project after having ascertained that it will not adversely affect the integrity of the European site (Regulation 63 (5)).Residential development increases the level of nutrients entering water systems through wastewater containing nitrogen and phosphorous from human waste, food and detergents. Although wastewater is sent to treatment plants to remove pollutants, the resulting effluent discharge eventually enters protected sites through local rivers. Achieving nutrient neutrality thus involves ensuring that the increased level of nutrients from wastewater associated with new development must be less than or equal to the nutrients generated by existing land use. This can be achieved by requiring developers to undertake mitigation measures, such as the construction of wetlands, to extract nitrogen from the land and counterbalance the nitrogen output from development.T

he objectors’ arguments in this case: detailed rulings on the nutrient neutrality advice

In the Solent Region, it is, according to Natural England’s guidance, essential to calculate a nutrient budget for any proposed development. The budget is derived from calculating any total increase in nitrogen that would arise as a result of the new development, with nutrient neutrality as the goal.The objectors argued that Natural England’s nutrient neutrality advice for the Solent Region was insufficiently precautionary so that the planning approval from Fareham Borough Council for 8 new dwellings, which relied upon the advice, was unlawful.Of particular relevance were objections that the advice was insufficiently precautionary in relation to (i) the 2.4 person per dwelling occupancy rate used to estimate the numbers of people in new dwellings; and (ii) the acceptance by the local planning authority (LPA) that areas of the development site had been used for “lowland grazing.” It was submitted that these considerations were both irrational, unreasoned and contrary to the precautionary principleThese two matters are important because, following Natural England’s advice, nitrogen values were assigned to these two considerations based on their relative output of nitrogen to the environment. These values were then used to calculate the nitrogen budget for the proposed development; a crucial step towards achieving nutrient neutrality. As the claimants believed the advice was insufficiently precautionary, this meant that the values assigned to these factors were either underestimated or overestimated. Therefore, although the nitrogen budget calculations purported to show a total credit of -4.5kg of nitrogen over the year, the claimants believed that this was incorrect; consequently offering less protection to the European site and failing to achieve nutrient neutrality.Mr Justice Jay rejected the allegation that the approach adopted by Fareham Borough Council was not sufficiently precautionary to meet the requirements of the Habitats Directive. The judge ruled that Natural England’s nutrient neutrality advice was not only correct, but “impeccable in all material respects,” ultimately concluding that the claimants had misunderstood the precautionary principle.

The “2.4 person occupancy rate”

The Natural England advice is based on the idea that it is crucial to calculate the additional population and subsequent water usage which would result from development in order to estimate the development’s total nitrogen output that would be discharged into Solent catchments through wastewater treatment centres. This is then used to inform the nutrient budget. Natural England’s advice recommended that as a starting point, LPAs should consider using the average national occupancy rate of 2.4 persons per dwelling as a basis for estimating the nitrogen output for the proposed development.It was submitted that because 2.4 was an average occupancy rate for all dwellings in England and Wales, irrespective of size, the figure was not precautionary. As the 8 new dwellings in this particular case were likely to be larger houses than average, it was submitted that a higher occupancy rate should be applied when calculating the nutrient budget. This is because it is assumed that a greater number of occupants produce a larger output of nutrient nitrogen, which later escapes into water systems. This was pivotal – the claimants believed that the nutrient output for the development as calculated by the developers was incorrect (ie an underestimate) if based on a 2.4 person occupancy rate, leading to an undesirable net nutrient gain and deterioration of the protected site.The judge dismissed this ground. Following examination of Ms Potts’ evidence from Natural England, the judge was satisfied that the figure was adequately precautionary and not irrational. The judge ruled that the methodology used to calculate the nutrient budget was precautionary due to the presence of other protective elements within it, such as the assumption that all occupants of each new dwelling were not already residing in the affected catchment, and that the water usage and discharge rates were not in direct proportion to the number of bedrooms in the proposed new dwellings (paragraphs 65, 68 and 86).The judge also stated that the LPA’s approach was further precautionary by applying a “precautionary buffer” to the calculations of the total nitrogen load that would result from the development (paragraph 44).Thus, despite evidence that the new dwellings may in fact contain 3 persons per dwelling, the average 2.4 figure was considered sufficient to calculate the nutrient budget because of the precautionary elements contained within the methodology and the existence of a precautionary buffer.

Classification of part of the land as being in “lowland grazing”

It was further submitted by the objectors that there was inadequate evidence to support the LPA’s acceptance that part of the site had been used for lowland grazing, implying that the area had been incorrectly classified as such. This is significant as different types of land are assigned varying nitrogen values dependant on their relative output of nitrogen, which is released by grazing animals.The planning officer allocated a nitrogen value to the area on the basis of its classification as used for lowland grazing. Lowland grazing involves a nutrient nitrogen output with an average value of 13.0kg/ha in the Solent catchment area. This output of nitrogen to the environment is then used to calculate the overall net nutrient gain or loss that would result from the proposed development.Accordingly, land used for “lowland grazing” receives a much higher nitrogen value (13kg/ha) in comparison to open grassland which is not used for agricultural purposes (5kg/ha). A lower value is more protective because it presumes that less nitrogen is being released into the environment from grazing animals. Therefore, when this is included in the nitrogen budget calculations, developers must be more diligent with the estimated nitrogen output from their development in order to achieve neutrality. Consequently, the claimants believed there was further danger of a net nutrient gain because the nutrient budget would be calculated with an overestimated and insufficiently precautionary value, falsely leading developers to believe that they could produce a greater nitrogen output than possible, yet still achieve nutrient neutrality from the proposed development.Despite contrary submissions by the Claimants, evidence was later presented that suggested the existence of a horse paddock, a licence agreement to permit previous grazing of horses, and a photograph depicting earlier presence of horses. As a result, the judge ruled that although the planning officer’s reasoning was not particularly expansive, he had correctly exercised professional judgement in concluding what use the land would be put to if planning permission were refused (paragraph 93).  According to the judge, it would defy common sense to suggest that this land would lie fallow if planning permission were refused. The judge therefore rejected this challenge, concluding that the classification of part of the land as being used for “lowland grazing” with a subsequently higher nitrogen value was sufficiently precautionary.

Significant HRA points of wide applicability from the judgment

 Mr Justice Jay ruled that under HRAs the answer to the “no adverse effect on integrity” test must be established at the point of consent. The judge stated that, in the present context, this meant the date the appropriate assessment is made (paragraph 31).The judge commented that no submissions were made to him in relation to departing from the case law of the European Court of Justice or the Court of Justice of the European Union. This is helpful for those hoping for something of a status quo (despite the UK leaving the EU) in relation to the case law on articles 6(2) and 6(3) of the Habitats Directive (paragraph 23).The judge also referred to the European Commission’s 2018 guidance document, “Managing Natura 2000 Sites the provision of Article 6 of the Habitats Directive,” suggesting that this guidance from the European Commission remains relevant in our domestic Court post Brexit.Mr Justice Jay clarified the required standard which must be attained by HRAs, stating “a high standard of investigation is demanded in line with the precautionary principle.” Although recognising that a requirement of absolute certainty would be impossible of scientific attainment and disproportionate, Mr Justice Jay reinforced Advocate General Kokott’s Opinion from the previous Waddenzee case that the burden on competent authorities means they must be “at least satisfied that there is no reasonable doubt as to the absence of adverse effects on the integrity of the site concerned.” (paragraph 32).The judgment elucidated the relationship between article 6(2) and article 6(3) of the Habitats Directive (paragraph 42). The claimants’ solicitor, Mr Gregory Jones QC, had submitted that when undertaking HRAs, planning authorities must also apply article 6(2) of the Habitats Directive. Mr Justice Jay explained how this submission “misses the point” – clarifying that article 6(2) of the Habitats Directive is considered by other bodies; planning authorities need only concern themselves with article 6(3) of the Habitats Directive when making planning determinations. Therefore, the importance of the positive obligation on EU Member States (including the UK through domestic law) to ensure that appropriate measures are taken by individuals other than planning authorities to avoid deterioration of protected habitats and species in Special Areas of Conservation has been reinforced by this judgment.Mr Justice Jay indicated that the overall essence of the precautionary principle is that “the uncertainty is addressed by applying precautionary rates…and in that manner reasonable scientific certainty as to the absence of a predicated adverse outcome will be achieved...” This emphasises that, as we remain “in the realm of the empirical sciences where uncertainty is inevitable,” an absence of scientific certainty cannot prevent development being permitted, further illustrating how the claimants’ argument was centred on this initial misunderstanding (Paragraph 45).The judge discusses the precautionary principle in greater depth at paragraphs 47 and 48, suggesting that it is incorrect to equate the precautionary principle with the “reasonable worst case scenario.” Mr Justice Jay also disagreed with Mr David Elvin QC’s submission that the precautionary principle embodies both proportionality and a degree of inherent flexibility. Nevertheless, the judge did suggest that where precise scientific data is unattainable, it may be appropriate and proportionate to draw from generic data and experience in analogous situations. However, “no value judgement as to the relevant worth of birds and mankind needs to be carried out.”Overall, and in spite of the specificity of this judgement to Natural England’s advice for the Solent Region, the case serves as an important reminder of the role of the precautionary principle – an answer to uncertainty.

If you wish to discuss anything covered in this article, please get in touch with Partner, Penny Simpson or Legal Assistant, Claudia Booth from our Environmental team.


The content of this page is a summary of the law in force at the date of publication and is not exhaustive, nor does it contain definitive advice. Specialist legal advice should be sought in relation to any queries that may arise.

Get in touch

Contact us today

Whatever your legal needs, our wide ranging expertise is here to support you and your business, so let’s start your legal journey today and get you in touch with the right lawyer to get you started.


Get in touch

For general enquiries, please complete this form and we will direct your message to the most appropriate person.