BNG Update: What’s Changing in 2026
The Government has set out a series of updates to Biodiversity Net Gain (BNG), with initial changes expected before July 2026 and further updates following consultation.
These changes will affect how smaller sites, brownfield developments, and certain exemptions are treated.
Changes Expected Before July 2026
- Small site exemption (≤0.2ha)
A new exemption is expected for minor developments below 0.2 hectares. This could remove the requirement for BNG on some smaller sites, particularly in urban areas. - Removal of self-build / custom build exemption
The existing exemption is expected to be withdrawn, bringing these developments into scope of mandatory BNG.
Further Changes Under Consideration
- Brownfield development approach
Proposed refinements aim to better reflect the constraints of dense urban sites, including more flexible habitat typologies and the use of proxy habitats where needed. - De minimis threshold (25m²)
Further clarification is expected on how small-scale impacts, particularly on urban sites, will be treated. - Nationally Significant Infrastructure Projects (NSIPs)
Mandatory BNG requirements have been delayed and are currently expected to come into force in November 2026. - Move towards digital metrics/tools
The current Excel-based biodiversity metric is expected to transition to a more standardised digital system over time.
What This Means
- Some smaller sites may fall out of scope, depending on final regulations
- Self-build routes will no longer avoid BNG requirements
- Brownfield sites remain complex, particularly where higher-value habitats are present
- Clarity on small-scale impacts is still evolving
- The tools and processes behind BNG are shifting, not just the policy
The Bottom Line
BNG isn’t standing still.
Some requirements are easing, others are tightening, and several areas remain in flux.
If you’re bringing sites forward this year, assumptions won’t hold for long.
If you don’t have up-to-date ecology data, you’re making planning decisions in the dark. Start with the survey.
If you need clarity on your site, get in touch.
BNG Changes:
One-Page Summary
We’ve created a clear breakdown of the confirmed and proposed 2026 BNG changes, what’s shifting, what’s staying, and where schemes are most exposed.
Download the one-pager and get up to speed in minutes.
