Legal Viewpoint: High Court provides clarity on weight for biodiversity net gain in planning balance

In this instance (Weston Homes Plc, R (On the Application Of) v Secretary of State for Levelling Up, Housing and Communities & Anor [2024] EWHC 2089 (Admin)), the claimant sought to challenge an inspector's decision, made on behalf of the secretary of state for Levelling Up, Housing and Communities under section 62A of the Town and Country Planning Act 1990, refusing permission for the erection of 96 homes on land which is largely open countryside. Section 62A allows for applications to be made directly to the secretary of state, where the relevant local planning authority for that area has been designated for this purpose. The application, which was amended from a previous scheme for 190 homes refused in 2022, also included 40 per cent affordable housing and the provision of public open space. 

The claimant was successful on four of the six grounds it advanced, namely that the inspector had:

• Erred in law when he “reduced the weight” given to the estimated biodiversity net gain (BNG) of the scheme “by taking into account a future legal requirement for BNG”; 
• Not given adequate reasoning to differ from the Inspector in the 2022 proposal in relation to the application's impact on the trees in the ancient woodland, Prior's Wood; 
• Erred in law when he considered that the nearby primary school expansion merely mitigated the effect of the scheme rather than seeing it as a “significant public benefit”; 
• Generally failed to give adequate reasoning for his decision. This ground of challenge was considered a “sweep-up” and so was not treated separately within the judgment.

The most interesting from a BNG perspective is the first ground. The proposed development was accepted to include an increase of 15.53 per cent in habitat units, 68.04 per cent in hedgerow units and 2.48 per cent in watercourse units. This means that, although the increase in BNG relating to the watercourse units was under ten per cent there would still be a gain. As Holgate J observed, neither the National Planning Policy Framework (NPPF), nor Uttlesford District Council's local plan, set a numerical target for BNG. 

The High Court found that, despite this gain, the inspector “gave less weight to BNG below 10 per cent than he otherwise would have done” when considering the NPPF “because it did not meet the new legislative requirement”. This implies that the inspector, in this instance, had given the BNG requirement retrospective effect, assessing the application on whether it reached the ten per cent mandatory requirement rather than what is required by the NPPF and local plan. 

As Holgate J states, this is “contrary to [the transitional provisions] and the decision in NRS Saredon”. Indeed, in NRS Saredon the High Court similarly found that the inspector had mistakenly judged any BNG against the new requirements, rather than giving it the proper weight considered appropriate under the policy in effect at the time the application was lodged. 

It is important to remember then that any BNG should be considered in the balance in relation to the policy at the time, rather than retrospectively. Ultimately, this decision is a helpful reminder on how to deal with BNG in applications, which were submitted prior to the new BNG regime, confirming the decision in NRS Saredon Aggregates Ltd v Secretary of State for Levelling Up, Housing and Communities [2023] EWHC 2795 (Admin).

Although not a contributing factor to the decision, the judgement also warns in its conclusion of the risks associated with using the procedure under section 62A of the Town and Country Planning Act – stating that the haste in which cases are conducted can “affect the quality of decision-making”. 

Case: Weston Homes Plc, R (On the Application Of) v Secretary of State for Levelling Up, Housing and Communities & Anor.

Date: 7 August 2024

Ref: [2024] EWHC 2089 (Admin)