Developments with a site area of 0.2 hectares or below will no longer be subject to mandatory biodiversity net gain (BNG) requirements from 6 August 2026, under changes to the Government's planning guidance.

The exemption applies to planning applications where the area of the development site within the red line boundary is 0.2 hectares or below. This removes the BNG requirement for smaller development proposals that previously fell within the scope of the rules.

The change could reduce the additional requirements facing developers of smaller sites, particularly where schemes have limited land available for biodiversity enhancements or face additional costs associated with meeting the 10% BNG requirement.

The updated guidance confirms that the change applies to planning applications made from 6 August 2026. Developers should therefore consider the site area within the red line boundary when determining whether BNG requirements apply to a new application.

The Government's guidance also sets out other categories of development that are exempt from BNG requirements, including certain developments below the relevant de minimis threshold and specified exemptions.