The Department for Environment, Food and Rural Affairs (DEFRA) has confirmed that there will be a change to the Biodiversity Net Gain (BNG) threshold from 31 July.

A new 0.2ha Exemption will apply from this date when any development on a site below this size will be BNG exempt.

DEFRA’s reforms also remove the Custom and Self-Build Housing exemption although most sites will be covered under the new 0.2ha Exemption.

It has also announced that temporary permissions for up to 5-years will be exempt.

Inevitably, there will be a interim period for existing projects which would benefit from this exemption, so it will be interesting to see whether local planning authorities take the forthcoming exemption into account when making decisions before 31 July.

There is also a step change in the hierarchy for Minor Development, whereby proposals meeting this definition will not be expected to provide their BNG on site.

There will be instead a level hierarchy where it is equally acceptable to deal with this on-site or off-site.

The preference in many cases will be for this to be off-site and moreover the government are proposing to dis-apply the spatial risk multiplier to make accessing off-site schemes easier.

There is a further consultation underway until 10th June 2026 to potentially exempt Brownfield Development sites up to 2.5ha in area. This would also be a significant positive step, so we will watch with interest and keep you updated.

Mandatory BNG was introduced in February 2024 for developers to deliver measurable gains for biodiversity alongside their developments.

A consultation was held in 2025 for views about changes to simplify BNG following feedback and evidence from the early stages of implementation with the changes now announced.

Please don’t hesitate to get in touch for more details about how these changes will affect your plans or project.