Yes. Since February 2024, biodiversity net gain has been a statutory requirement for most developments in England. This isn't a planning policy that authorities can choose to apply or that applicants can negotiate around—it's embedded in primary legislation through Schedule 7A of the Town and Country Planning Act 1990, inserted by the Environment Act 2021.
The practical effect is that planning permissions now automatically include a biodiversity gain condition. Applicants must demonstrate at least 10% net gain in biodiversity value, calculated using the Defra Metric, and that gain must be secured and maintained for 30 years.
The requirement was phased in over 2024:
Major developments (larger housing schemes, significant commercial projects, and similar) became subject to mandatory BNG from 12 February 2024. Any planning application submitted from that date onwards attracts the biodiversity gain condition.
Minor developments followed on 2 April 2024. This brought smaller projects—including most residential developments below the major threshold—into the regime.
Nationally Significant Infrastructure Projects have a later start date of November 2025. These are the largest infrastructure schemes (power stations, major transport projects, large-scale utilities) that go through the Development Consent Order process rather than standard planning. The delay recognises their longer lead times, but mandatory BNG is coming for them too.
For applications submitted before these dates, BNG isn't legally required—though many authorities encouraged it through local policy, and the Weston Homes case confirmed that decision-makers shouldn't penalise older applications for not meeting the 10% standard that didn't yet apply to them.
The requirement has teeth in ways that matter practically.
You can't lawfully start development until your Biodiversity Gain Plan is approved. The biodiversity gain condition is a pre-commencement condition. Holding a valid planning permission isn't enough—if the LPA hasn't signed off your Gain Plan, breaking ground is a breach of planning control.
You can't opt out or buy your way around it (cheaply, anyway). The 10% requirement applies regardless of site constraints, project economics, or how inconvenient it is. Developers who can't achieve gains on-site must secure off-site units or, as a last resort, purchase statutory credits from the government at deliberately punitive prices (currently around £42,000 per credit, with two credits required per unit—far above market rates for habitat bank units).
The obligation runs for 30 years. Habitat creation or enhancement isn't a one-off cost at planning stage. The legal agreements securing BNG—whether section 106 obligations or conservation covenants—bind the land for three decades. Management, monitoring, and maintenance continue long after the development is complete.
LPAs are expected to enforce. Government guidance confirms that local planning authorities should monitor BNG delivery and take enforcement action where commitments aren't met. The same tools used for other planning breaches—breach of condition notices, injunctions, court action—apply to BNG failures.
The mandatory requirement has exemptions. Householder development (extensions, outbuildings within a dwelling's curtilage), development below de minimis thresholds (less than 25 square metres of habitat or 5 metres of hedgerow affected), self-build housing, and certain permitted development are outside the regime.
Importantly, the requirement only applies in England. Scotland, Wales, and Northern Ireland are considering similar measures but haven't yet implemented equivalent legislation. Cross-border developers need to track which regime applies to which site.
And irreplaceable habitats—ancient woodland, veteran trees, limestone pavements—sit outside the standard BNG framework entirely, but because they receive stronger protection rather than weaker. Impacts on irreplaceable habitat can't be offset through the unit trading system.
BNG represents a genuine shift in how English planning treats ecology. Before 2024, biodiversity was a material consideration—something planners weighed in the balance—but there was no consistent national standard for what "acceptable" looked like. Developments could proceed with mitigation that reduced harm without necessarily producing any net benefit.
The 10% mandatory requirement changes that calculation. Every covered development must leave biodiversity measurably better than before, using a standardised metric that allows comparison and verification. The intent is systemic: if every development contributes positively, the cumulative effect should be meaningful habitat creation and restoration across the country.
Whether that intent translates into genuine ecological outcomes depends on implementation—on the quality of habitat created, the rigour of 30-year management, and the willingness of authorities to enforce. But the legal framework is now in place, and developers who treat BNG as optional will find their projects unable to proceed.
EcoCapital supplies off-site BNG units through a nationwide habitat bank network, all registered with Natural England. For developers navigating mandatory BNG for the first time, the team provides a free initial consultation to review baseline surveys, planning conditions, and the most cost-effective route to compliance.
Units can be reserved pre-planning, locking in supply before the Biodiversity Gain Plan deadline. Eco Capital handles the registration paperwork and long-term habitat management, so the 30-year obligation is met without ongoing burden on the developer.
