Biodiversity Net Gain 

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

In England, biodiversity net gain is set out under Schedule 7A of the Town and Country Planning Act 1990 (as inserted by Schedule 14 of the Environment Act 2021).

The Environment Act 2021 makes a 10% biodiversity net gain (BNG) mandatory for all but exempt and small sites from 12 February 2024 and for small sites from 2 April 2024.  From these dates, all qualifying planning applications will need to include the minimum national information (set out in Article 7 of The Town and Country Planning (Development Management Procedure) (England) Order 2015) to be valid.

A general biodiversity gain condition of planning permission will be used to secure the biodiversity gain objective which is to deliver at least a 10% increase in relation to the pre-development biodiversity value of the development site. 

The general biodiversity gain condition is a pre-commencement condition. Once planning permission has been granted, a biodiversity gain plan (BGP) must be submitted and approved by the District Council before the development can commence. The biodiversity gain plan must show how the development will achieve biodiversity net gain using on-site enhancement and/or offsite habitats and/or statutory biodiversity credits.

Biodiversity Net gain must be measured using the statutory biodiversity metric or, for some small sites, the small sites statutory biodiversity metric can be used. The metric is a habitat-based approach to determining a proxy biodiversity value and is a means of assessing changes in biodiversity value (losses or gains) brought about by development or changes in land management. 

Significant on-site enhancement and all off-site habitats must be secured for at least 30 years via conditions, planning obligations or conservation covenants. As a last resort, where developers are unable to use on-site or off-site units to deliver biodiversity net gain (BNG), they can buy statutory biodiversity credits.  

Biodiversity net gain, however, is not just a post-permission matter. As well as the minimum national information requirements the developer will need to provide sufficient information to demonstrate that the general biodiversity gain condition is capable of being discharged successfully through the imposition of conditions and agreement of Section 106 planning obligations to secure significant onsite biodiversity gains and registered offsite biodiversity gains. 

Where significant onsite enhancements are proposed, a habitat management and monitoring plan will be required to ensure the habitats are maintained and monitored over 30 years. 

The BNG requirement does not change the existing legal protections for important habitats and wildlife species. It maintains the mitigation hierarchy of avoid impacts first, then mitigate and only compensate as a last resort. 

For more information see the collection of guidance and links at the Biodiversity Net Gain collection.   This includes the BNG Planning Practice Guidance.