Mandatory biodiversity net gain (BNG) rules rolled out for small sites

Farmers may encounter BNG requirements as a result of their own development, and/or to deliver BNG for the private market
Farmers may encounter BNG requirements as a result of their own development, and/or to deliver BNG for the private market

Mandatory biodiversity net gain (BNG) requirements for small developments have now gone live, two months after the initial roll out.

From February, BNG has been mandatory for new planning applications for major development made under the Town and Country Planning Act (TCPA) 1990.

This includes residential developments with 10 or more dwellings, or where the site area is greater than 0.5 hectares.

BNG for small sites had an extended transition period, which was rolled out on 2 April 2024.

Small sites are defined as residential developments where the number of dwellings to be provided is between 1-9 on a site area less than 1ha or where the number of dwellings to be provided is not known the site area is less than 0.5 hectares.

It is also defined as non-residential sites where the floor space created is less than less than 1,000 square meters or where the site area is less than 1ha.

The BNG rules mean that developments - unless exempt - need to restore any biodiversity lost during the building phase and deliver a 10% minimum boost to the area’s biodiversity.

This can be achieved by creating or enhancing biodiversity in association with a development, which can be onsite, offsite or through statutory biodiversity credits as a last resort.

The habitat created should be the best replacement for the habitat lost through development, the government said.

The Country Land and Business Association (CLA) said BNG was an important policy to support ambitions for nature recovery .

"It is right that any development or infrastructure project should make up for any biodiversity losses," the rural body said.

“There is still work to do to fully establish the market for biodiversity units, with a need for greater transparency and more standard contracts to reduce the transaction costs.

“BNG is rightly encouraged to go onsite, but the CLA would also like to see a greater emphasis on offsite provision, which can be provided by landowners in the local area to help reconnect habitats over the landscape.”

According to NFU advice, farmers may encounter BNG requirements as a result of their own development or to deliver BNG for the private market.

Despite some exemptions to BNG, the union said that farm developments may still be impacted by the requirement to deliver a 10% minimum boost to the area’s biodiversity.

And for some farmers, the opportunity for private sector investment in environmental land management practices may provide a useful new income stream.