Biodiversity Net Gain Update - February 2026

Consultation on a targeted exemption for residential brownfield development (potentially ≤2.5 ha)

Brownfield sites can include high-distinctiveness habitats such as open mosaic habitat, which can prove challenging to offset. We await further detail on what the targeted exemptions may be and how offsetting of habitats with high ecological value will be dealt with.

Introduction of an area-based BNG exemption for smaller sites (≤0.2 ha)

On smaller development sites, BNG deficits are often fractional, making the offsetting cost disproportionately high relative to the transaction value. This is due to fixed transaction costs, which can make the development financially unviable. Such an exemption would mitigate this issue.

New rail and densification policies

The drive for more development could also result in more gains for biodiversity, with more developments needing to meet the 10% BNG requirement.

Limiting the circumstances in which plan-makers can seek BNG contributions to exceed the statutory requirement

Simplification of the BNG process is welcomed, though it’s unclear if this would result in less biodiversity gains being delivered both on- and off-site.

Simplification of the BNG process for SMEs and a new medium sized site category for 10–49 units (or ≤2.5 ha)

More proportionate regional BNG requirements are welcomed. Current policy does not adequately distinguish between the need for community greenspace and for biodiversity enhancements. Where a region has limited accessible greenspace, there should be greater prioritisation for on-site habitat creation that provides recreational space, while greener regions should focus on off-site BNG where there are much lower levels of human disturbance enabling biodiversity enhancement to be maximised.

BNG to apply to Nationally Significant Infrastructure Projects (NSIPs)

We await a response on the BNG consultation for NSIPs in May 2026. We are encouraged by the uptake of the BNG policy already by many major infrastructure providers who have been meeting or exceeding the 10% BNG requirement voluntarily. Therefore, we expect the transition to mandatory BNG for NSIPs being smooth.