BNG Reforms in 2026

BNG mandatory for NSIPs from 2 November 2026

Mandatory BNG will apply to all NSIP applications submitted on or after 2 November 2026 — later than the originally expected May 2026 start, giving promoters additional preparation time. NSIPs are the largest developments in England, consented through Development Consent Orders under the Planning Act 2008.

A uniform 10% net gain requirement applies across all NSIP types. BNG is assessed using targeted boundaries — only habitats negatively affected by the development are included in the baseline. Off-site units may be sourced from any LPA, NCA or Marine Plan Area that the NSIP BNG boundary falls within, with no spatial risk multiplier penalty. A biodiversity gain plan must be submitted alongside the DCO application.

Defra plans to lay the secondary legislation and publish updated biodiversity gain statements aligned with National Policy Statements in May 2026, with further guidance ahead of the 2 November go-live.

New 0.2 hectare area-based exemption

All development where the site area inside the red line is 0.2 hectares or less will be fully exempt from BNG. Defra estimates this will remove BNG requirements from around half of the residential planning permissions previously in scope.

Important: the exemption does not apply where priority habitats (habitats of principal importance) are present. Sites within or affecting a priority habitat must still comply. Secondary legislation is expected before 31 July 2026.

Self-build and custom build exemption removed

The existing self-build and custom-build exemption is being removed. In practice, most such projects will fall under the new 0.2ha threshold instead, so the net effect for most small builders is neutral or positive.

Equal-status off-site delivery for minor developments

For minor developments — residential schemes with 9 or fewer dwellings on a site of 1 hectare or less — off-site biodiversity delivery now has equal status with on-site delivery, loosening the strict mitigation hierarchy.

This makes it materially easier for small developers to find a workable BNG solution without redesigning the scheme around on-site habitat creation.

Three new targeted exemptions

Three further targeted exemptions are being introduced:

Biodiversity-led developments — schemes whose primary objective is to conserve or enhance biodiversity are exempt.

Temporary planning permissions granted for a maximum of 5 years are exempt, unless on-site priority habitats are affected.

Parks, playing fields and public gardens — developments enhancing these spaces are exempt.

Spatial risk multiplier reform — LPA/NCA → LNRS

The spatial risk multiplier — the metric penalty applied when off-site units come from outside the development's local area — will be assessed against Local Nature Recovery Strategy (LNRS) areas instead of LPA and NCA boundaries.

There are only 48 LNRS areas across England, compared with 337 LPAs. The pool of off-site units that can be used without attracting a spatial risk multiplier is therefore very substantially expanded, particularly for developers in densely-bordered regions.

Targeted brownfield residential exemption

A consultation open until 10 June 2026 asks whether predominantly residential brownfield schemes should be exempt from BNG (in addition to the confirmed 0.2ha exemption). "Brownfield residential development" is proposed to be defined as schemes where at least 75% of the site is Previously Developed Land.

Size thresholds under consideration are 0.5, 1, 1.5, 2 or 2.5 hectares. Any exemption would not apply where priority habitats are affected. Commercial-led or mixed-use schemes with only a minor residential element would remain subject to BNG.

Local Nature Recovery Strategies

Over half of all Local Nature Recovery Strategies (LNRS) have now been adopted across England, with the remainder expected during 2026. LNRSs identify priorities and locations for nature recovery and directly influence the strategic significance multiplier.

The spatial risk multiplier reform (see above) elevates LNRS areas as the core geographic unit for off-site BNG sourcing — making LNRS alignment increasingly important for habitat bank operators and landowners.

NPPF changes affecting BNG

Proposed changes to the National Planning Policy Framework may restrict the ability of local authorities to push mandatory BNG beyond 10% through local plans. The government has also stated that BNG is not in scope of broader planning reform deregulation, providing stability for the core 10% requirement.