Skip to content

What is Biodiversity Net Gain?

From January 2024, most housing, industrial and commercial developments in England will be required to provide 10 percent biodiversity net gain (BNG). To prove how the habitats and biodiversity are going to be delivered, developers will have to provide an in-depth management plan covering at least 30 years, which must be approved by the local planning authority (LPA).

The Environment Act sets out the following key components of mandatory biodiversity gain:

  • Amends Town & Country Planning Act (TCPA);
  • Minimum 10% gain required to be calculated using the Biodiversity Metric & approval of a biodiversity gain plan;
  • Habitat secured for at least 30 years via planning obligations or conservation covenants;
  • Delivered on-site, off-site, or via a new statutory biodiversity credits scheme; and National Register for net gain delivery sites.
  • It does not change 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. It will apply to Nationally Significant Infrastructure Projects (NSIPs) but not marine development.

From April 2024, Biodiversity Net Gain will also become mandatory for small sites. For reference, small sites are defined as:

  • For residential; where the number of dwellings to be provided is between one and nine inclusive on site having an area of less than one hectare, or where the number of dwellings to be provided is not known, a site area of less than 0.5 hectares.
  • For non-residential: where the floorspace to be created is less than 1,000 square metres OR where the site area is less than one hectare.