Biodiversity net gain in planning applications

Biodiversity net gain became mandatory for major and non-major development made under under the Town and Country Planning Act (TCPA) 1990, subject to the exemptions or transitional provisions set out below.

Biodiversity net gain planning practice (opens in new tab)

Eligible developments must meet the mandatory requirement of a minimum 10% biodiversity net gain over the pre-development biodiversity value of the site.

a statement as to whether the planning permission, if granted, would be subject to the biodiversity gain condition. Applicants are expected in this statement to set out what exemption(s) or transitional provision(s) apply to the development
proposed date of the pre-development (baseline) biodiversity value, if this is before the date of submission, as the planning authority needs to agree to this date
a completed statutory biodiversity metric (opens in new tab) for the pre-development (baseline) biodiversity value of the proposed development site
a scaled plan showing the pre-development (baseline) on-site habitat
confirmation of whether there have been any activities (habitat degradation) that would make the baseline biodiversity value lower as a result of the activities. If this is the case, the baseline biodiversity value is taken as immediately before the activities.

The BNG section of the planning application form will help you to provide the minimum information required. We have prepared guidance to help you complete the BNG section of the planning application form.

Guidance for planning application form (opens in new tab)

The metric should be completed by a competent person with specialist knowledge of habitat types and conditions, such as an ecologist, who can advise on the calculations. You can find an ecology consultant on the CIEEM website.

Visit the CIEEM website (opens in new tab)

Make sure you:

use the statutory metric (opens in new tab) as early as possible in the site design process to help avoid biodiversity loss
follow the biodiversity gain hierarchy (opens in new tab) which prioritises on-site BNG first
consider how BNG can be optimised at design stage
consider how the location of on-site biodiversity relates to adjoining habitats, green corridors or existing green space within the site and beyond the red line boundary
consider how suitable multi-functional biodiversity enhancements can form part of the site’s landscaping and amenity space strategy
undertake all other ecological assessments. Biodiversity net gain does not replace any of the existing wildlife protections and we must still address any potential ecological impacts in planning decisions.

Validation

Minimum information requirements for BNG are set out in Article 7 of The Town and Country Planning (Development Management Procedure) (England) Order 2015 (opens in new tab) . Without this information, your application will not be validated.

The minimum information requirements are primarily provided through the planning application form and we have prepared guidance to support applicants.

Read the guidance on completing your application form (opens in new tab)

Applicants are encouraged to submit as much information on their post-development BNG proposals as possible with their application.

This will support consideration of whether the mandatory minimum 10% BNG is achievable, provide understanding of how the BNG is expected to be delivered (on-site/off-site) and how it will need to be secured, and to meet Local Plan Policy NE1 requirements.

Exemptions

The exemptions from mandatory biodiversity net gain, as set out in paragraph 17 of Schedule 7A of the Town and Country Planning Act 1990 (opens in new tab) and the Biodiversity Gain Requirements (Exemptions) Regulations [2024] (opens in new tab) are:

Section 73 planning permission where the original planning permission was exempt (for example, the original planning permission was submitted prior to 12 February 2024)
householder applications
development granted planning permission by a development order under section 59 (includes permitted development rights)
developments below the ‘de minimis’ threshold (less than 25m² of area habitat or 5m linear, for example hedgerow, line of trees, watercourse, habitat and no priority habitat)
self-build and custom build applications which meet the exemption criteria (no more than nine dwellings, site no larger than 0.5ha, consists exclusively of dwellings which are self-build or custom housebuilding as defined in section 1(A1) of the Self-build and Custom Housebuilding Act 2015)
urgent crown development granted under s293A TCPA 1990
development of a biodiversity gain site that is solely or mainly for the purpose of fulfilling the biodiversity gain condition for another development
development related to the high speed railway transport network.

For full details see the following guidance:

Biodiversity net gain: exempt developments (opens in new tab)

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