This one isn’t a SAP input, but it lands on the same desks we work with every day — housebuilders, small developers and the planning teams around them. On 6 August 2026 a first batch of changes to Biodiversity Net Gain (BNG) came into force in England, and if you bring forward smaller sites, the paperwork just got lighter. Grab a brew; we’ll keep this short.
The quick recap on BNG
Since February 2024, most developments needing planning permission under the Town and Country Planning Act have had to deliver a 10% biodiversity net gain — leaving habitat measurably better than before, on-site where possible, or off-site or via statutory credits where not. It’s been a real workload for small schemes in particular, where the assessment cost can be out of proportion to the site.
The government consulted on easing that burden last year, responded in April 2026, and has now made the first legislative changes through The Biodiversity Gain (Town and Country Planning) (Amendment) Regulations 2026 (SI 2026/790), laid before Parliament on 13 July and in force from 6 August (Defra Environment blog, 14 July 2026).
What actually changed on 6 August
Four things, per Defra’s confirmation:
- A new 0.2-hectare exemption. The smallest developments — sites of 0.2 ha or less — no longer have to do mandatory BNG, unless on-site priority habitat would be negatively impacted. This is the headline: it takes a large slice of minor applications out of the regime entirely.
- A new temporary-development exemption. Development on land that will be reinstated within five years or less is exempt — again, unless on-site priority habitat is negatively impacted.
- A relaxed hierarchy for minor development. Minor sites that aren’t exempt (for example, those over 0.2 ha) can now go straight to off-site provision in the first instance, rather than having to work through the on-site-first hierarchy.
- The self- and custom-build exemption is removed. The old blanket carve-out for self- and custom-build is gone. Those projects now sit under the ordinary rules — so a small self-build may instead pick up the new 0.2-hectare exemption, but it isn’t exempt simply for being self-build.
Defra is clear that exempt developments are still expected to incorporate nature-friendly features, and that existing environmental protections and the planning mitigation hierarchy continue to apply — permission should still be refused where significant harm to biodiversity can’t be avoided, mitigated or, as a last resort, compensated (updated Planning Practice Guidance).
The date that matters: applications from 6 August
This is the bit to get right. The changes apply only to new applications for planning permission made from 6 August 2026. Anything already submitted before that date continues under the existing BNG rules — the exemptions don’t retro-apply. So the question for any given scheme is simply: when was (or will) the application be made?
What’s still coming
This is a first batch, not the whole reform. Defra has signalled further changes to follow from the April response, including exemptions for development whose primary purpose is to conserve or enhance biodiversity, a targeted exemption for works to parks, playing fields and public gardens, and updates to the statutory biodiversity metric. Separately, the consultation on a possible exemption for certain residential brownfield development closed on 10 June 2026, with a government response still to come. In short: more movement to expect, but nothing else in force yet.
What this means for you
If you advise on or appraise smaller residential sites, it’s worth re-checking your live pipeline against the 0.2-hectare threshold and the application date — some schemes that were budgeting for BNG assessment and units may no longer need them, while anything already in the system stays as it was. And keep priority habitat front of mind: it’s the condition that switches every one of these exemptions off.
Working on the environmental side of a stalled or marginal site? Our nature and nutrient tools can help you scope obligations before you commit spend — take a look here.