The evolving position on BNG for the TCPA regime

As the recent BNG focus has been on the DCO regime, with the 10% requirement becoming mandatory from 2 November 2026, we wanted to revisit the evolving position for the TCPA regime. My colleague Matthew Tucker and I explore this below.

Legislative update

The most recent legislative change in the BNG regime was the introduction of the Biodiversity Gain (Town and Country Planning) (Amendments and Transitional Provisions) (England) Regulations 2026 which came into force on 6 August 2026. The changes introduced by these Regulations include exceptions for sites under 0.2 hectares in size and for temporary developments with a term of less than 5 years. The Regulations also modify the BNG hierarchy to give on-site BNG and registered off-site BNG the same weight; however, this only applies in respect of non-major developments.

There has also been the recent announcement in the Budget of the intention to extend the exceptions to 1.5 hectare brownfield sites. 

Policy update

Changes made in the latest NPPF provide additional clarification around when developers can be required to exceed statutory BNG.  Policy N1 of the NPPF confirms that “development plans should only set local standards for biodiversity net gain which are in excess of the statutory net gain requirement where this is for specific site allocations, and is fully justified and deliverable. Local standards should not extend to categories of development which are exempt from statutory biodiversity net gain.”

Furthermore, policy N2 of the NPPF sets out that “development proposals may incorporate biodiversity enhancements which exceed the statutory objective for biodiversity net gain, but this should only be a requirement where it is set out in up-to-date development plan policies for specific site allocations. Decision makers should not give weight to other development plan policies which require biodiversity gains which go beyond the statutory framework, including where a policy requires gains for development proposals which are exempt.”

These policies suggest that in most cases the provision of BNG will need to be limited to the statutory 10% unless a higher standard is secured in a specific site allocation that is fully justified and deliverable, although this does not prevent developers from voluntarily choosing to deliver a higher level of BNG in their development.

Appeals

A couple of recent appeal decisions are also worth highlighting as Inspectors have grappled with niche questions regarding BNG. 

In an appeal decision dated 5 October 2026 (appeal reference: 6008794), the Inspector found the mandatory BNG legislation did not apply to retrospective permissions granted under section 73A of the TCPA 1990. The transitional regulations (regulation 2(2) of the Environment Act 2021 (Commencement No. 8 and Transitional Provisions) Regulations 2024) expressly provide that the BNG regime applies to planning permissions granted from 12 February 2024 and specifically exclude development where permission is sought for works already carried out. Planning practice guidance also confirms that BNG does not apply to retrospective applications made under section 73A (paragraph: 003 Reference ID: 74-003-20240214). The Inspector concluded that the statutory biodiversity gain condition, which is imposed automatically on qualifying permissions and operates as a pre-commencement requirement, was unnecessary. This appeal highlights the importance of understanding the scope of BNG requirements. 

In an appeal decision dated 17 September 2026 (appeal reference: 6008247), the Inspector considered a planning application was invalid because it lacked mandatory biodiversity net gain information. Article 7(1A) of the Town and Country Planning (Development Management Procedure) (England) Order 2015 requires planning applications to include information about the biodiversity gain condition. Although the appellant had originally stated that the proposal qualified for the "de minimis" exemption, the parties agreed during the appeal that this did not apply and that the planning application should have included required BNG documentation. Although the planning application had been validated by St Albans City & District Council, the Inspector advised that this decision was not binding on the Secretary of State and concluded that the appeal could not progress under section 79(6) of the Town and Country Planning Act 1990. This appeal serves as a reminder to carefully review the BNG strategy in circumstances where there is uncertainty about whether a BNG exemption applies.

Way forward

Please do not hesitate to contact Matthew Tucker or Jen Ashwell if you would like to discuss the BNG requirements relating to a TCPA scheme.