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Biodiversity Net Gain is live!

But what is it?

Biodiversity Net Gain (BNG) is an approach to development designed to ensure that there is a positive impact, or net gain, on biodiversity compared to what was there pre-development. 

From and including 12 February 2024, unless exempt, every grant of planning permission under the Town and Country Planning Act 1990 will be deemed to be granted subject to a general BNG condition to secure that the “biodiversity gain objective” is met. That biodiversity gain objective is that the biodiversity value attributable to the development exceeds the pre-development biodiversity value of the onsite habitat by at least 10%.

Will it apply to my development?

If you are developing land, it’s likely that the general BNG condition will apply. 

However, not all developments will be subject to BNG from 12 February:

  • the BNG requirement for “small sites” will not be introduced until 2 April 2024; and
  • the BNG requirement won’t apply for nationally significant infrastructure projects until 2025.

Some developments are also exempt from BNG regulations:

  • developments below the threshold - a development that does not impact a priority habitat and impacts less than 25 square metres of habitat and 5 metres of linear habitat such as hedgerows;
  • householder applications – these are applications made by householders as defined within article 2(1) of the Town and Country Planning (Development Management Procedure) (England) Order 2015 and includes, for example, small projects like home extensions;
  • self-build and custom build applications when the development consists of no more than 9 dwellings, is on a site that has an area no larger than 0.5 hectares and consists exclusively of dwellings that are self-build or custom house building as defined in section 1(A1) of the Self-build and Custom Housebuilding Act 2015;
  • biodiversity gain sites ; and
  • any development forming part of, or ancillary to, the high-speed railway transport network.

What do I need to do?

If BNG applies to your development, you’ll need to deliver a BNG of 10%, as measured by the statutory biodiversity metric developed by DEFRA which measures biodiversity in standardised “biodiversity units” taking different factors into account such as the size, condition, location and type of the habitat. 

You can deliver the 10% BNG:

  1. on the development site itself; 
  2. off-site, either on land belonging to the developer or by purchasing off-site biodiversity units available on the market; or
  3. by purchasing statutory biodiversity credits from the government.

However, there is a hierarchy; developers must follow, and demonstrate that they have considered, these three options in order (combining them is an option) with buying statutory biodiversity credits as a last resort. 

Another major consideration is that the habitat created to deliver the BNG objective must be maintained for at least 30 years. You must legally secure off-site gains or significant on-site gains which will be done by way of a legal agreement (a planning obligation or a conservation covenant agreement) or planning condition.

You’ll need to consider the impact of BNG on your planning process. The BNG condition is a pre-commencement condition so once planning permission has been granted you’ll need to submit a “biodiversity gain plan”, showing how the development will achieve BNG, and the local planning authority must approve it before the development commences. 

The new BNG regime is a positive step in contributing to wildlife recovery whilst developing land however, there is no doubt that this significant development in the planning legislation leaves developers with many issues to consider and onerous obligations to discharge as part of the development process. Considering BNG at the outset, or at least in the early stages, of your development process is highly recommended; early consultation with an ecologist is going to be important here, in terms of site selection, assessment of BNG value of on-site and potentially off-site land, and how BNG is going to be delivered and maintained. 


real estate, biodiversity, planning, biodiversity net gain