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Biodiversity net gain
What is biodiversity net gain?
Biodiversity net gain (BNG) is an approach to development and/or land management that aims to leave the natural environment in a measurably better state than it was beforehand. The word 'biodiversity' comes from the term 'biological diversity'.
Why is it important?
The Environment Act 2021 introduced the duty to deliver minimum 10% BNG through planning decisions; this requirement was enacted on 12 February 2024. This is a mandatory requirement – applicable developments have to demonstrate 10% net gain otherwise we may not be able to approve them.
Under the statutory framework for biodiversity net gain, subject to some exceptions, every grant of planning permission is deemed to have been granted subject to the condition that the biodiversity gain objective is met (“the biodiversity gain condition”).
The biodiversity gain condition is a pre-commencement condition: once planning permission has been granted, a Biodiversity Gain Plan must be submitted and approved by the planning authority before commencement of the development. You must provide evidence for some of your BNG decisions.
The National Planning Policy Framework (NPPF) notes that improving biodiversity is one of the objectives to deliver sustainable development. the NNPF refers directly to providing net gains for biodiversity.
The adopted Swindon Local Plan contains Policy EN4 (Biodiversity and Geodiversity), which requires development to avoid negative impacts and for applicable developments also to provide biodiversity net gain.
Does it affect all planning applications?
The requirement to demonstrate statutory BNG applies to all applications subject to some exemptions.
What do applicants have to do?
As a result of the mandatory need for delivering BNG applicants will need to provide sufficient information with their planning applications to allow the council to make an informed judgement on this issue.
You must include:
- a statement confirming whether the applicant believes that planning permission, if granted, would be subject to the biodiversity gain condition
- the pre-development biodiversity value of the on-site habitat on the date of application (or an earlier date) including the completed metric calculation (showing the calculations, the publication date and version of the biodiversity metric used to calculate that value)
- the proposed earlier date and the reasons for that date, where the applicant wishes to use an earlier date
- a statement confirming whether the biodiversity value of the on-site habitat is lower on the date of application (or an earlier date) because of the carrying on of activities (‘degradation’)
- the relevant date immediately before these activities were carried out, where unauthorised degradation has taken place between 30 January 2020 and the submission of the planning application
- a description of any irreplaceable habitat on the land, that exists on the date of application (or an earlier date)
- a plan drawn to an identified scale (including the direction of north), showing on-site habitat existing on the date of application (or an earlier date), and any irreplaceable habitat
Please note: If this information has not been provided, we may refuse to validate the application.
Developers need to assess the pre-development state of a site to calculate its biodiversity value. You must submit the Statutory or Small Sites Biodiversity Metric in Excel format (unlocked), with your application, to demonstrate how a minimum of 10% net gain will be delivered; we require on-site provision as the priority.
If you do propose offsite biodiversity gain, either via the purchase of offsite biodiversity units from a registered site, by creating a new registered gain site on land you own, or purchasing National Credits, you will need to provide a statement explaining how the Biodiversity Hierarchy has been considered.
If planning permission is granted, a Biodiversity Gain Plan needs to be prepared and submitted to the council prior to commencement of development. This will set out the final strategy for achieving BNG, including all relevant information, habitat management plans and how the net gains will be managed and maintained.
Further guidance and a template gain plan is available via the government website.
Whilst on-site provision is the priority, if off-site BNG is accepted as a solution we will require evidence that biodiversity units or National Credits have been purchased from a registered source and that they are allocated to your development.
Further information on how to set up and register a biodiversity gain site can be found below: