BNG regime and nationally significant infrastructure projects
updated on 12 November 2024
Question
Prior to the introduction of the mandatory biodiversity net gain (BNG) regime for nationally significant infrastructure projects in November 2025, does a developer need to be considering BNG in relation to an application for a Development Consent Order made in the next 12 months?Answer
Background to BNG
Biodiversity net gain (BNG) is a policy in England aimed at enhancing biodiversity through development. Introduced as part of the Environment Act 2021, BNG mandates that most new developments achieve a minimum uplift of 10% in biodiversity value compared to pre-development levels. This requirement is designed to ensure that development projects leave the natural environment in a measurably improved state. The policy stipulates that any biodiversity gains must be secured for a minimum duration of 30 years.
The original scope of the BNG requirement, introduced by the Environment Bill in October 2019, was limited to applications under the Town and Country Planning Act 1990 (1990 act). This scope was expanded in 2021 to include nationally significant infrastructure projects (NSIPs) under the Planning Act 2008 (2008 act). This expansion resulted in a comprehensive BNG framework that encompasses two distinct application processes: one for developments falling under the 1990 act and another for those governed by the 2008 act.
Implementation timeline and framework
The government adopted a phased approach for implementing the mandatory BNG regime. The BNG requirements for planning applications under Schedule 7A of the 1990 act were implemented from 12 February 2024 in relation to major developments and from 2 April 2024 for small sites (as defined in The Town and Country Planning (Development Management Procedure) (England) Order 2015)).
Schedule 15 of the Environment Act 2021 (2021 act) sets out the prospective BNG provisions under the 2008 act, which will apply to NSIPs, being large-scale planning works concerned with energy, transport, water, wastewater, and waste. Instead of applying for planning permission through the local authority (as it would if the application was made under the 1990 act), the applicant applies for a Development Consent Order (DCO) through the Planning Inspectorate, which then makes a recommendation to the relevant Secretary of State.
BNG requirements for NSIPs
The government plans to implement the BNG requirements for projects that are accepted for examination by the Planning Inspectorate under the NSIP regime from November 2025. The key points to note under Schedule 15 of the 2021 act are:
- the Secretary of State must make a BNG statement containing a BNG objective, which will apply to all DCOs during a specified period;
- the statement must require a BNG value increase of at least 10%, mirroring the required gain for planning permission, although the Secretary of State has the power to make a BNG statement requiring additional BNG;
- the statement must make provision that if a DCO includes land already registered on the BNG register, the value of pre-development habitat for the purposes of the DCO includes the value of the existing habitat enhancement;
- the statement must set out whether and how the BNG objective applies to irreplaceable onsite habitat; and
- the statement must set out what evidence is required from any DCO applicants to demonstrate how the BNG objective is met.
There are subsequent provisions that set out procedure, if any developments are, or aren’t, covered by an existing national policy statement at the time at which Schedule 15 of the 2021 act is implemented.
Once the draft BNG statement is finalised and incorporated into the relevant National Policy Statements for different types of infrastructure, it’ll provide clear guidance on how BNG should be incorporated into DCO applications and establish criteria for Secretaries of State to consider when making decisions on BNG aspects of NSIPs.
Voluntary adoption of BNG principles for NSIPs
There’s evidence that developers are already voluntarily integrating BNG principles into their NSIP proposals before mandatory implementation. A notable example is the recent approval of a DCO for National Grid's Bramford to Twinstead Reinforcement project in September 2024. National Grid committed to achieving at least a 10% biodiversity gain as part of its Environmental Action Plan for 2021 to 2026. The decision letter confirmed that while the government intends to commence mandatory BNG for NSIPs from November 2025, it supported National Grid's decision to commit to BNG on a voluntary basis ahead of the mandatory requirement being introduced.
This approach of voluntary adoption is echoed in updated energy National Policy Statements, which ‘encourage’ applicants to utilise biodiversity metrics and present outcomes in their submissions and, among other documents, the revised National Policy Statement for National Networks, which has been amended to state that applicants ‘should’ include their metric calculations in applications.
Conclusions
BNG is already becoming a key factor for NSIPs in England. With just one year left until BNG becomes mandatory for NSIPs, the Planning Inspectorate and examining authorities are increasingly scrutinising biodiversity improvements during project examinations. Adopting a proactive approach to incorporate BNG principles into project designs now is a sensible strategy. This enables developers to identify and mitigate any potential impacts on project viability stemming from future BNG requirements at an early stage.
Harriet Grimes is a senior associate and Adrian Bennett is a solicitor at Michelmores LLP.
