Biodiversity net gain (BNG) is an approach to development that aims to leave the natural environment in a measurably better state than it was beforehand.

From the following dates, it is mandatory for new developments under the Town & Country Planning Act 1990 (as amended) to provide a minimum 10% biodiversity net gain (BNG) with a 30-year management and monitoring obligation secured by planning obligation:

  • 12th February 2024: Major Developments
  • 2nd April 2024: Small Developments

Unless exempt, planning permissions will be deemed to be subject to a mandatory biodiversity gain planning condition.

10% biodiversity net gain will need to be demonstrated through the statutory biodiversity metric.

Land degraded since 30th January 2020 without planning permission (or since 25th August 2023 with planning permission) will be assessed against evidence of baseline value prior to degradation.

A biodiversity gain plan will need to be submitted by applicants to meet the requirements of the new mandatory biodiversity gain condition. Development may not begin until the biodiversity gain plan is approved.

There are also separate new requirements relating to irreplaceable habitats.

This is a major change to the planning system, embedded in the development management process.