Biodiversity net gain

National policy

The delivery of BNG is set to become a mandatory requirement of the planning system from January 2024 onwards. It directly affects people who need to secure planning permission for new projects above a certain size. It will be unlawful to issue a planning approval for any qualifying project that does not secure 10% BNG, with 30-year management and monitoring.

This will apply to small sites from April 2024, and implementation for Nationally Significant Infrastructure Projects is planned for 2025.

The National Planning Policy Framework (2023) sets out that planning policies and decisions ‘should contribute to and enhance the natural and local environment, by minimising impact on and providing net gains for biodiversity…’

National Planning Practice Guidance sets out further  detail of what net gain is.

The Environment Act (2021) contains a new BNG condition for planning permissions.

Guidance on how to calculate biodiversity can be found on the Gov.uk website

The government has indicated that it will be providing secondary legislation, guidance, and tools to support the implementation of this policy prior to mandatory requirements coming into force..