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Biodiversity Net Gain (BNG)

Biodiversity Net Gain is an approach to development that leaves biodiversity in a measurably better state after development than before, after first avoiding and minimising harm.

From 12 February 2024 all major developments in England will have to deliver 10% BNG and from 2 April 2024 all developments (except for some exceptions, such as householder applications) will have to deliver 10% BNG. This requirement does not replace, but is in addition to, the existing policy and legal requirements related to biodiversity and development.

To measure BNG and assess the impacts of planning applications Defra’s Biodiversity Metric (or for smaller sites the small sites metric) should be used. Guidance on how councils across Gloucestershire expect the biodiversity metric to be used is provided below (this guidance is regularly updated to reflect changes in national and local guidance and initiatives):

Biodiversity Net Gain: Good practice principles for development (published by CIEEM) should be followed when designing developments and preparing planning applications. Further advice can be obtained from the council via our pre-application advice service.

Planning applicants will need to provide information on the biodiversity value of their application site and how they plan to deliver 10% BNG as part of their application. Details can be found on our validation webpages.

In most cases, BNG should be provided on the development site (particularly where proposals impact designated sites, irreplaceable habitats or priority habitats), but 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 planning applicant’s control or via another landowner or BNG broker. The council has worked with the Gloucestershire Nature and Climate Fund to enable a supply of potential off-site BNG delivery locations. 

Government guidance on the BNG process is available at: