Biodiversity Net Gain (BNG)

Mandatory Biodiversity Net Gain (BNG) - New Planning requirements

The Environment Act 2021 introduces new requirements that all planning permissions granted in England (with a few exemptions) must deliver at least 10% biodiversity net gain, using the Government’s metric that generates a biodiversity value for a site before and after development to demonstrate this. Secondary legislation and associated guidance have now been published and sets out the following information:

  • Mandatory BNG applies to applications submitted for major development from 12 February 2024 and to applications submitted for development on Small Sites from 2 April 2024;
  • Where mandatory BNG applies, applicants must use DEFRA’s Statutory Biodiversity Metric and meet the national minimum information requirements;
  • Householder development will be exempt from mandatory BNG, along with permitted development and most proposals which impact a very small (less than a 25m2 area or 5m linear) habitat;
  • Relevant developments will be subject to a general pre-commencement planning condition. This planning condition will require that developers submit, and have approved by the council, a ‘biodiversity gain plan’ before any works can begin;
  • The ‘biodiversity gain plan’ describes how the developer will achieve a 10% BNG, informed by a biodiversity metric assessment. This is a standardised template for the ‘biodiversity gain plan
  • If 10% BNG cannot be achieved within the red line boundary of the planning approval, offsite habitat creation will need to be relied upon. The ‘biodiversity gain plan’ will need to evidence this.

The Government has published a 'collection' of guidance to support the delivery of mandatory BNG, including a National Planning Practice Guidance on Biodiversity Net Gain.  Applicants should refer to this guidance when preparing to submit a planning application.