What is changing?
From 6 August 2026, several important changes will come into force for the BNG framework.
The changes are designed to make the process more proportionate for smallest developers and local planning authorities, while still making sure larger schemes deliver important biodiversity improvements.
The main changes are:
• A 0.2ha exemption for developments on sites of 0.2ha or less, as long as no priority habitats are affected
• A temporary development exemption for some temporary schemes, where land will be reinstated within five years (unless onsite priority habitat is negatively impacted)
• A more flexible biodiversity gain hierarchy for minor development, allowing minor sites that are not exempt from BNG, such as sites over 0.2 hectares, to secure off-site mitigation offsite from the outset
• The removal of the self and custom build exemption, meaning these developments will need to meet mandatory BNG requirements unless other exemption applies
Transitional arrangements
The changes will broadly apply only to new planning applications made on or after 6 August 2026.
Applications submitted before 6 August 2026, or already permitted before that date, will continue to be considered under the existing BNG legislation.
For variations to existing applications, where the original application or permission predates 6 August 2026, the current BNG position is expected to continue to apply in most cases.
What happens next?
Further changes to the BNG legislation are expected after the 6 August 2026. These are likely to include:
• An exemption for development where the main purpose is to conserve or enhance biodiversity
• A targeted exemption for development that improves parks, playing fields and public gardens
• Updates to the statutory biodiversity metric
The government has also recently consulted on a possible targeted exemption for some residential brownfield development. A response is expected in the coming months.
