BNG Calculatorv4.0 / JP039
Statutory Biodiversity Metric v4.0 (JP039)· Defra GOV.UK guidance, last updated 2 June 2026· NSIP extension live 2 November 2026· Reviewed 21 June 2026

BNG brownfield exemption consultation: live tracker (June 2026)

Defra has consulted on a brownfield-specific exemption that could extend up to 2.5 ha of qualifying brownfield land; the proposal is live but not enacted as of June 2026.

Awaiting MCIEEM peer review · CIEEM (Chartered Institute of Ecology and Environmental Management)

What the consultation proposes

A staged exemption for qualifying brownfield sites up to 2.5 ha; the qualifying test would include previously developed land status, absence of priority habitat (including post-industrial habitats of substantive nature conservation value), and explicit LPA acceptance of brownfield designation.[S10]

Interaction with the 0.2 ha small-sites exemption

The brownfield carve-out would sit alongside the existing 0.2 ha small-sites exemption; both would be available where qualifying. A small brownfield infill under 0.2 ha would be covered twice over; the brownfield route only matters for the 0.2 to 2.5 ha band.

Consultation status and response window

The consultation is hosted on Defra’s consultation portal; check the live status for the response deadline. Developers, planning agents, and ecology firms can respond directly.

Implementation timeline

Defra has signalled that any brownfield exemption would be enacted via secondary legislation after the post-implementation review reports back; realistic earliest implementation is 2027. The site will be updated when a Statutory Instrument is laid.[S10]

Not yet law
As of 21 June 2026 the brownfield carve-out is a consultation proposal, not enacted law. Treat all numerics in this page as the consultation position; the calculator does not apply a brownfield exemption.