Mandatory biodiversity net gain goes live

Biodiversity net gain (BNG) is now a legal requirement for most new housing developments.

After implementation was delayed twice, from November and last month, applications for new schemes in England of more than nine dwellings will now need to achieve an uplift in BNG of at least 10%.

As part of the Environment Act 2021, mandatory BNG will help deliver the government’s commitment to halt species decline by 2030, according to the Department for Environment, Food & Rural Affairs (DEFRA).

DEFRA also said government was helping local planning authorities with BNG through £10.6m of funding for the recruitment and expansion of ecologist teams and “green jobs” investment. Local authorities also have a “range of tools” to help “enforce” BNG.

BNG, according to DEFRA, means “there will be more nature after a development than before”. The 10% uplift is measured in biodiversity units which are calculated through DEFRA’s statutory metric tool. This calculates how many units a habitat contains before development, leading to how many biodiversity units are needed to provide the at least 10% improvement.

The statutory biodiversity metric considers habitats in terms of units, according to size, quality, location and type of habitat.

Housebuilders can achieve BNG through onsite units, offsite units (biodiversity units can also be bought through a private market), or, as a last resort, statutory biodiversity credits bought from the government.

The new biodiversity gain “hierarchy” prioritises onsite BNG, where housebuilders create new habitats or enhance existing ones on the development site.

Also under the legislation, significant on site and all offsite gains must be maintained for at least 30 years. This requires a legal agreement with a responsible body or local authority to monitor the habitat improvements over the 30-year period.

BNG will apply to new planning applications, not those existing. It will apply to small sites between one and nine homes from April 2.

This Friday (February 16), the Home Builders Federation will host a webinar on mandatory BNG between 12.30pm and 1.45pm via Zoom.

The webinar, available to HBF members and featuring a panel of experts, will cover the requirements, the guidance available and the steps housebuilders can take to achieve BNG.

HBF said that while mandatory BNG aligned with housebuilders’ ongoing efforts to protect and enhance natural environments, it would impact an already complex planning system, with delays considered a significant barrier to homes delivery as revealed in the latest State of Play report, focusing on SMEs.

Sam Stafford, HBF’s planning director, said:

“BNG is already being achieved on developments across the country, delivering significant benefits to residents and the environment. However, operational challenges must not be underestimated. Ensuring there are viable options available – particularly for small sites – is vital and expectations must be managed as this new way of working beds in.

“While the developers of larger sites have been increasingly including BNG on their developments, for smaller sites, where it is not possible to deliver onsite solutions, there is a reliance on offsite credits, the availability of which is a challenge in some areas, with the market still in its infancy.”