April 2026

Biodiversity Net Gain procedural updates ease the delivery of development

The results of the consultation on ‘Improving the Implementation of BNG’ (May 2025) were released by DEFRA on 16 April 2026. This signals that a range of updates to the BNG process will be brought forward from as early as July 2026. These updates are generally seen as positive and assist the practical drafting and implementation of Biodiversity Gain Plans through revisions to the approach taken to certain elements. Of these, there are five updates of particular interest:

1. Delivery of off-site BNG facilitated as spatial multiplier is recalibrated

Local delivery of off-site BNG provision is favoured and assessed within the metric by a ‘spatial risk multiplier’. Under the revisions, the administrative boundaries used for the multiplier will move to Local Nature Recovery Strategy (LNRS) boundaries rather than the current ‘Local Planning Authority (LPA)/National Character Area (NCA)’ boundaries.

‘Local’ provision is currently classed as being within the same ‘LPA/NCA’, while ‘adjacent’ provision is classed as being within a neighbouring ‘LPA/ NCA’. The proposed change simplifies matters and significantly broadens the availability of local or neighbouring off-site BNG delivery. At present there are 337 LPAs and 159 NCAs, whereas there are only 48 LNRS areas.

2. A new 0.2 hectare exemption

Developments where the site area is less than 0.2 hectares will be exempt from BNG requirements. This is a new exemption rather than an expansion of the existing de minimis rule, which applies to impacts affecting less than 25m² (5m x 5m) of habitat.

The new exemption will not apply where on-site Priority Habitats are affected, and the mitigation hierarchy must still be followed (i.e. habitats cannot simply be removed because BNG does not apply).

3. Minor developments to see off-site BNG delivery facilitated

For minor developments (1–9 dwellings) that are not subject to the 0.2 hectare exemption, off-site biodiversity gains will now be treated equally to on-site gains.

4. Self-build exemption to be removed

The current exemption for self-build and custom-build development will be removed. The rationale is that the majority of such sites will instead fall within the new 0.2 hectare exemption.

5. Temporary permissions receive relief

A new exemption will be introduced for development that is temporary, where the permission duration is limited to five years or less. This is aimed at schemes where the land will subsequently be restored, making BNG compliance disproportionately difficult or expensive.

This exemption will not apply where on-site Priority Habitats are affected.

Nationally Significant Infrastructure Projects

The Government has confirmed that BNG will apply to Nationally Significant Infrastructure Projects (NSIPs) from November 2026, following publication of its response to the parallel ‘Biodiversity Net Gain for Nationally Significant Infrastructure Projects Consultation’ (May 2025).

It further advises that NSIPs will operate under the existing BNG framework and will be able to source BNG units from any LNRS area through which the project passes, without penalty under the Metric’s ‘spatial risk multiplier’.

Brownfield sites

DEFRA launched a new consultation on 15 April 2026 titled ‘Considering a Targeted Exemption for Residential Brownfield Development’.

DEFRA is seeking views on whether a potential exemption from Biodiversity Net Gain (BNG) requirements for certain brownfield residential developments is needed to better support residential development on brownfield land, in line with the Government’s brownfield-first approach and wider proposals to accelerate housing delivery on well-connected urban sites.

Views are sought on the definition of brownfield land, potential exemption thresholds (with brownfield sites between 0.5 and 2.5 hectares being considered), and measures to ensure that any exemption remains environmentally robust.

The consultation closes on 10 June 2026.

Conclusion

The above measures should result in a modest easing in the drafting and delivery of biodiversity net gain requirements and demonstrate that the Government continues its agenda of facilitating the practical and timely delivery of development.

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