Biodiversity Net Gain Changes Announced: What Developers Need to Know

The Government has announced a significant update to the Biodiversity Net Gain (BNG) regime, with a series of regulatory changes due to come into force on 6 August 2026. These amendments are designed to reduce the administrative burden on the smallest developments while ensuring that larger schemes continue to deliver meaningful environmental improvements.

At Collington Winter Environmental, we help developers, landowners, planning consultants and local authorities navigate the evolving BNG framework. Below, we explain what the latest changes mean and how they may affect future planning applications.

The Government consultation can be found here.

A new exemption has also been introduced for certain temporary developments. Where land will be fully reinstated within five years or less, mandatory BNG will no longer be required, provided the proposal does not negatively impact priority habitat.

This exemption could apply to a range of temporary uses, including construction compounds, temporary facilities and other short-term developments where land will ultimately return to its previous condition.

The Government has also amended the biodiversity gain hierarchy for minor developments. Previously, applicants were generally expected to prioritise onsite biodiversity enhancements before considering offsite solutions.

Under the new rules, minor developments that are not exempt from BNG (for example, sites exceeding 0.2 hectares) will have greater flexibility by allowing them to move directly to offsite biodiversity gains where appropriate.

This change should make it easier to deliver practical BNG solutions where onsite habitat creation is limited by site constraints.

While new exemptions are being introduced, one existing exemption is being removed. The previous exemption for self-build and custom-build developments will no longer apply. These developments will now be assessed under the same BNG framework as other planning applications, unless another exemption is available.

Developers undertaking self-build projects should therefore consider BNG requirements at an early of the planning process.

Although some developments will become exempt from mandatory Biodiversity Net Gain, environmental responsibilities have not disappeared.

Developments benefiting from the new exemptions will still need to comply with wider planning policies and environmental legislation.

Planning authorities will continue to apply the mitigation hierarchy, requiring developers to:

• Avoid harm to biodiversity wherever possible
• Minimise impacts where they cannot be avoided
• Mitigate any remaining effects
• Provide compensation only as a last resort

Planning permission may still be refused where significant ecological harm cannot be adequately addressed.

The Government has also made it clear that exempt developments are still expected to incorporate nature-friendly design features wherever possible, helping to support biodiversity even where formal BNG requirements do not apply.

The changes only apply to new planning applications submitted on or after 6 August 2026. Applications already submitted before this date, along with existing planning permissions, will continue to be assessed under the current Biodiversity Net Gain regulations.

This distinction is important for developers with schemes currently progressing through the planning system.

As Biodiversity Net Gain continues to evolve, obtaining specialist ecological advice remains essential. Whether your development is likely to qualify for one of the new exemptions or still requires a full BNG strategy, understanding your obligations from the outset can save both time and cost during the planning process.

At Collington Winter Environmental, we provide comprehensive BNG services, including Preliminary Ecological Appraisals, habitat surveys, Biodiversity Metric calculations, Biodiversity Gain Plans and advice on onsite and offsite habitat enhancement. Our experienced ecologists work closely with developers and planning professionals to ensure projects remain compliant while delivering practical and sustainable outcomes.

If you are preparing a planning application, our team can help you determine how the new regulations apply to your site and guide you through every stage of the Biodiversity Net Gain process.