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Biodiversity Net Gain assessment and guidance

Published: 2022-11-15 Updated: 2023-03-21 Subject: Planning

Local planning requirement

Use this page to quickly locate the guidance and tools you need to successfully deliver Biodiversity Net Gain (BNG) requirements for your development.

Read about the policy context and ideas behind Biodiversity Net Gain requirements

National Guidance

The delivery of BNG is to become a mandatory requirement of the planning system and is set to come into effect from November 2023. It directly affects people who need to secure planning permission for new projects above a certain size. It will be unlawful to issue a planning approval for any qualifying project that does not secure 10% BNG, with 30-year management and monitoring.

The Government will be providing secondary legislation, guidance, and tools to support its implementation of this policy.

West of England (WECA) guidance

The West of England Combined Authority are producing guidance. We will make this accessible as soon as this has been made available. 

Local interim guidance

We have produced guidance (see below to view or download documents) to support the implementation of Local Plan Partial Update (LPPU) policy in this interim phase. This guidance reflects our best understanding of developing BNG practice.

Biodiversity Net Gain Units 

As a landowner, we are exploring ways that off-site habitat gains can be successfully achieved and delivered, including the role Council land could play.

All planning projects subject to BNG requirements should consider Biodiversity from the very outset, prior to site design, and ideally at site selection stage. This should help minimise the need for providing replacement habitats. 

BNG practice is still in development, so the guidance provided here is likely to evolve. Please check this page for updates, directly before submitting your planning application.

For more information about our BNG off-site provision projects, please email us at

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