Biodiversity Net Gain: Mandatory Requirements Now Apply
Mandatory Biodiversity Net Gain of at least 10% now applies to the majority of planning permissions in England. Architects must integrate BNG assessments into the design process from the outset.
Mandatory Biodiversity Net Gain (BNG) under Schedule 7A of the Environment Act 2021 came into force for major developments in February 2024 and for small sites in April 2024.
The 10% Requirement
All new developments (with limited exemptions) must demonstrate a minimum 10% BNG above the pre-development baseline, measured using the DEFRA Biodiversity Metric tool.
The Biodiversity Gain Plan
Before development can commence, a Biodiversity Gain Plan must be submitted to the LPA showing how 10% gain will be achieved on-site, off-site, or through biodiversity credits.
Design Implications
- Ecological surveys should be commissioned at Stage 1 or 2 (RIBA PoW)
- Green roofs, living walls, and habitat creation can contribute to BNG
- Early liaison with ecologists and landscape architects is essential
The 30-Year Management Plan
BNG gains must be maintained for a minimum of 30 years. Architects should advise clients on long-term management obligations.