England has now switched on the legal machinery for biodiversity gain in nationally significant infrastructure projects under section 99 and Schedule 15 of the Environment Act 2021. For Eco Current readers, the important point is simple: the country’s biggest schemes, from large renewable energy projects to airports, ports and major roads, are moving towards a planning test that measures nature outcomes rather than treating them as a side note. (legislation.gov.uk) The timing matters. Defra says the statutory instruments and biodiversity gain statements for all NSIP types are being laid in May 2026, but the mandatory biodiversity net gain requirement is set to apply to development consent order applications made on or after 2 November 2026. That gives developers, planners and communities a short preparation window rather than an overnight rule change. (gov.uk)

A biodiversity gain statement is not just another planning note. In law, it is a statement of government policy that sets the biodiversity gain objective, explains how gains are calculated and states what evidence applicants must provide. Where a relevant statement applies, the Secretary of State cannot grant consent unless satisfied that the project meets that objective. (legislation.gov.uk) For sectors with an existing National Policy Statement, the biodiversity gain statement must be added at the next review, and ministers can issue a separate statement in the meantime. Where no National Policy Statement exists, the Secretary of State can issue a standalone statement after consultation. Schedule 2A also sets a clear floor: the gain objective must be at least 10% above the pre-development biodiversity value of the on-site habitat. (legislation.gov.uk)

In practice, this should push biodiversity work much earlier into site selection, scheme design and pre-application discussions. Defra’s own summary says promoters should avoid or minimise habitat loss first, use the statutory biodiversity metric before an application is submitted, and file an Outline Biodiversity Gain Plan with the development consent order application. That is a more disciplined process than treating habitat compensation as a late-stage add-on. The final sentence is an inference from the process Defra has set out. (gov.uk) It also makes the evidence trail much more concrete. The current model text applies only to the parts of NSIPs in England, including intertidal areas up to the mean low-water mark. Before works start, applicants will need updated or phase biodiversity gain plans, evidence of units already secured, and a route to close any remaining shortfall. Off-site gains can be used, but they must be registered, statutory biodiversity credits sit at the back of the queue as a last resort, and habitats created or enhanced for gain must then be managed and monitored for at least 30 years. (gov.uk)

This is landing in a country that badly needs stronger habitat recovery. The State of Nature 2023 partnership found that around one in six species are at risk of extinction in Great Britain. Against that backdrop, tying major infrastructure consent to measurable habitat gain and long-term management is not a niche planning tweak; it is a concrete test of whether growth policy can also repair nature. (brc.ac.uk) Public pressure is already visible. Defra received 10,403 responses to its NSIP biodiversity net gain consultation, with 10,143 coming through an RSPB campaign. Many respondents argued that 10% should be a baseline, not the ceiling, because these schemes are large and long-lasting. (gov.uk)

The economic case in government papers is more balanced than the usual build-versus-nature caricature. Defra’s final impact assessment for the preferred NSIP approach estimates a best-estimate net benefit of about £3.7 billion over 30 years, alongside an annual net cost to business of £30.7 million. In other words, the rule is not cost-free, but ministers argue that the public value of better habitat and species recovery is materially bigger than the compliance bill. (assets.publishing.service.gov.uk) The same assessment says roughly 800 to 1,000 hectares of land are developed into NSIPs each year. Defra expects that avoiding biodiversity loss on those sites and securing at least 10% net gain could improve flood management, carbon sequestration, air and water quality, recreation and local amenity. For communities near major schemes, that is where this dry legal change becomes visible on the ground. (assets.publishing.service.gov.uk)

The next test is delivery. Defra says it will publish guidance, an updated metric user guide and biodiversity gain statements for all NSIP types, while working with the Planning Inspectorate and local planning authorities before the November 2026 go-live. If that guidance is clear, the new rule could make expectations firmer earlier in the consent process and cut some avoidable argument later on. That final point is an inference, not a government guarantee. (gov.uk) For now, the message is practical rather than dramatic. Big infrastructure in England is entering a phase where habitat value has to be counted, evidenced and maintained, not just acknowledged in principle. If ministers, developers and councils use the months before 2 November 2026 well, biodiversity gain statements have a real chance to make better development and better habitats pull in the same direction. (gov.uk)