Biodiversity net gain is a government strategy to ensure that habitat for wildlife is in a better state than it was before development. The habitat is in effect used as a proxy for calculating biodiversity.
The Government have hailed this to be a significant milestone in the delivery of their Environmental Improvement Plan, to ensure new development contributes to the recovery of nature and to meet the target to halt the decline in species abundance by 2030.
What is happening from 12 February 2024?
In England, a biodiversity plan will be mandatory for new planning applications for major development (includes residential developments with 10 or more dwellings, or where the site area is greater than 0.5 hectares) made under the Town and Country Planning Act 1990 (TCPA), subject to confirmed exemptions. Developers will be required to set out how the post-development biodiversity value must improve by at least 10% of the biodiversity value on the site prior to development. This increase in biodiversity value is “the Biodiversity Net Gain”. These changes have been introduced by virtue of the Environment Act 2021 (Commencement No 8 and Transitional Provisions) Regulations 2024 (Sl 2024/4).
Exemptions:
- ‘Small sites’ (includes residential development where the number of dwellings is between 1 and 9, or where the site area is less than 0.5 hectares) for which the mandatory requirement will not be introduced until 2 April 2024 by virtue of the Biodiversity Gain Requirements (Exemptions) Regulations 2024 (SI 2024/47).
- It is believed that this approach is intended to lessen the burden on local authorities.
- Nationally Significant Infrastructure Projects for which the mandatory requirement will not apply until late November 2025.
- Planning applications which are not made under the TCPA – Regulations will be needed to make BNG apply to these.
- Developments which do not impact an onsite priority habitat (as set out in a list published under section 41 of the Natural Environment and Rural Communities Act 2006) where the impact of the development will be minimal.
- Householder applications.
- Planning permissions in relation to high speed railway transport networks.
- Biodiversity gain sites.
- Self-build and custom build applications.



