Biodiversity Net Gain (BNG)

The Council’s adopted saved LDF Core Strategy Policy CS22 requires all new development to produce a net gain in biodiversity by designing in provisions for wildlife.

From 12 February 2024 all new planning applications for MAJOR development will need to explain at the application stage how they will provide at least a 10% Biodiversity Net Gain as per national legislation. For MINOR applications the start date for 10% BNG is 2 April 2024. A number of exemptions apply.

View guidance for developers and land managers.

The biodiversity gain objective of at least a 10% gain is measured against the pre-development biodiversity value of the onsite habitat for the development using the statutory biodiversity metric tools:

The general biodiversity gain condition will be automatically applied to all non-exempt developments.

Once permission is granted it will be necessary to submit a ‘Biodiversity Gain Plan' for approval ahead of the commencement of development:

Submit a biodiversity gain plan

The Council will apply a hierarchy to the approval of Biodiversity Net Gain:

  1. On site mitigation – strong preference
  2. Off site (within Southampton)
  3. Off site (out of City)
  4. Statutory credits (last resort)

Clearing sites in advance

Within Schedule 14 of the Environment Act measures have been included that allow the local planning authority to take account of any habitat degradation or destruction undertaken on a site since January 2020 , and to take the earlier habitat state as the baseline for the purposes of biodiversity net gain. This is to ensure that there is no advantage to be gained by the deliberate clearance of land in order to achieve a low baseline value for biodiversity net gain.

If habitats on site have been destroyed or degraded prior to a survey and submission of planning application, the earlier habitat state will be taken as the baseline for the purposes of the biodiversity metric and a habitat condition score of ‘good’ will be allocated to the habitat parcel as a precaution.