Biodiversity net gain (BNG)

Biodiversity net gain is a way of creating and improving biodiversity by requiring development to have a positive impact (‘net gain’) on biodiversity.

Under the Environment Act 2021, most developments (with limited exemptions such as certain householder applications) must deliver a minimum of 10 percent Biodiversity Net Gain. This requirement applies in addition to existing planning policy and legal protections for biodiversity.

We expect all development proposals to comply with national legislation, the National Planning Policy Framework (NPPF), and adopted local plan policies relating to biodiversity, green infrastructure, and sustainable development.

To measure BNG and assess the impacts of planning applications, applicants must use the statutory Biodiversity Metric published by Defra (or the Small Sites Metric, where applicable).

You should follow the Biodiversity Net Gain: Good Practice Principles for Development (published by CIEEM) when designing proposals and preparing planning applications. We strongly encourage you to involve us at an early stage through our pre-application advice service.

Planning applications must include:

• A completed biodiversity metric calculation
• Baseline habitat information
• Details of how at least 10 percent BNG will be achieved
• Information required under the statutory biodiversity gain condition

Full validation requirements can be found on our website.

In most cases, BNG should be delivered on-site, particularly where proposals affect designated sites, irreplaceable habitats, or priority habitats. In some cases, and in agreement with the council, it may be necessary to provide the net gain off-site. This could be on land within the applicant’s control, via agreement with a third-party landowner, through a habitat bank, or via statutory biodiversity credits as a last resort.

Further Guidance

Gloucestershire Local Nature Recovery Strategy and BNG

Local Nature Recovery Strategies (LNRSs), introduced by the Environment Act 2021, are spatial strategies designed to guide nature recovery and expand the Nature Recovery Network across England.

Gloucestershire County Council has been appointed by Defra as the responsible authority for the Gloucestershire LNRS. The Gloucestershire LNRS was published on 13 February 2026 and identifies biodiversity priorities and maps areas where habitat creation and enhancement will deliver the greatest ecological benefit across the county, including within Cheltenham Borough.

Developers should use the Gloucestershire LNRS to:

•    Inform green infrastructure design
•    Identify opportunities for habitat creation, enhancement, and restoration
•    Guide the location of on-site and off-site BNG delivery
•    Maximise the strategic significance of habitat proposals within the biodiversity metric

Habitats created or enhanced in areas identified within the LNRS may attract higher strategic significance within the statutory metric. Please visit GOV.UK for the statutory biodiversity metric user guides which give guidance on assigning strategic significance.

Planning applications must demonstrate how the LNRS has been considered in the design and delivery of BNG. Strategic significance must be clearly evidenced within the metric submission.

We encourage you to seek advice from a suitably qualified ecologist when determining appropriate habitat creation, enhancement, restoration, and long-term management measures. Alternatively, you can use our pre-application advice service.

The statutory biodiversity gain condition

All relevant planning permissions are subject to the statutory biodiversity gain condition. Development can't lawfully commence until this condition has been discharged.

The statutory biodiversity gain condition may appear as an informative on the decision notice, but it still has full legal effect.

To discharge the condition, applicants must submit:

• A Biodiversity Gain Plan
• Confirmation of the biodiversity value of the on-site habitat
• Details of the post-development biodiversity value
• Any off-site biodiversity gain allocations
• Information on habitat management and monitoring arrangements

Further advice on how to discharge this condition can be found here.

 

Related Pages

• Wildlife and biodiversity
• Make a planning application
• Discharging the statutory biodiversity gain condition