Biodiversity net gain becomes a legal requirement for major developments

10% Biodiversity Net Gain (BNG) became a legal requirement for major developments from 12 February 2024. This requires major planning applications to provide a minimum of 10% net gain in biodiversity.

Major planning applications for dwellinghouses are defined as a development of 10 or more, or development on a site of 0.5 hectares or above where the number of dwellings is not known.

If a building or buildings create 1,000 sq m of floor space or more, or if the site has an area of 1 or more hectares (for example, commercial development), BNG requirements will also apply.

Applicants who consider their proposals exempt from BNG will have to justify their position. Where BNG applies, applicants will need to include a completed biodiversity metric, a scaled plan showing the direction of north and onsite habitat, and an ecology or multiple ecology surveys.

Where 10% BNG cannot be achieved on the site, then addressing it outside the development site may be considered, and there is also an option to buy off-site biodiversity units on the market. As a last resort, applicants may need to purchase statutory credits from central government.

The exceptions to the rule

Biodiversity net gain requirements have a number of exemptions, including, for example:

• Householder development
• Self-build
• Custom-build development of not more than 9 dwellings

From 2 April 2024, BNG requirements will roll out and be a requirement for non-major planning applications too, unless exempt or below a set threshold.

Further biodiversity net gain guidance is likely from central government as it rolls out in practice.

Lydia Pravin is an associate planning director based in our Peterborough office. For more information on how BNG will affect you, contact her on [email protected] or on 01733 666913.