Mandatory NSIP biodiversity gain now applies to development consent order applications made in England from Monday 2 November 2026. The change extends the requirement for at least 10% biodiversity net gain to nationally significant infrastructure projects, from major electricity works to roads and water infrastructure. For promoters preparing to submit, the relevant date is when the application is made, not when design work began.
The legal framework did not first appear this morning. The Environment Act 2021 (Commencement No. 11) Regulations 2026 brought the relevant Planning Act 2008 provisions into force on 7 May. The biodiversity gain statements specify 2 November as the point from which the new obligation applies to DCO applications. That distinction matters for projects already travelling through the national consent process.
This is a practical change to what applicants must demonstrate, not a new consultation or a ministerial promise. Ecological surveys, the statutory metric, construction footprints, proposed gain land and legally enforceable management arrangements now need to be considered as part of the consent case. For complex projects, the choice of temporary working areas can affect the result as much as the permanent infrastructure.
What NSIP biodiversity gain requires from today
Under Schedule 2A to the Planning Act 2008, the biodiversity gain objective must be at least 10%. Defra’s current NSIP guidance confirms that development consent order (DCO) applications made from today must demonstrate how they will achieve that gain. This is measured in biodiversity units using the statutory biodiversity metric, rather than by simply adding a percentage of extra landscaped land.
The relevant biodiversity gain statement is essential. Defra published statements for different infrastructure sectors in June, and they have the same effect as if included in the relevant National Policy Statement. The Secretary of State must consider the applicable statement when deciding a DCO. Our guide to National Policy Statements explains that broader decision-making framework.
NSIP biodiversity gain does not replace the normal mitigation hierarchy. Avoiding and reducing ecological harm still comes first, and the habitat calculation sits alongside environmental impact assessment, protected-sites duties and other planning considerations. The new regime should therefore change design choices early, rather than become a calculation added after the chosen route or site is fixed.
The application date is the dividing line
The 2 November 2026 trigger is the date a DCO application is made. An application submitted before today is not pulled into mandatory NSIP biodiversity gain merely because its examination, recommendation or ministerial decision takes place afterwards. Equally, substantial pre-application work before today does not exempt a new application lodged from today onwards.
The statutory machinery was introduced by SI 2026/492, with effect from 7 May, rather than by a newly made instrument on 2 November. What changes today is the practical application of the biodiversity gain statements to new DCO applications. Describing today as the first commencement of the Environment Act provisions would get that chronology wrong.
Defra also distinguishes projects consented through other legislative routes, including hybrid Bills. Developers should establish the actual consenting route before assuming the DCO regime applies. This is not a second commencement of biodiversity net gain for ordinary Town and Country Planning Act applications, most of which have had separate BNG requirements since 2024.
What must be ready when a DCO is submitted?
Applicants need an outline biodiversity gain plan, a statutory metric calculation and evidence explaining the baseline, the habitats affected and the proposed delivery of gains. Defra expects a single metric calculation for the project even where associated works are physically separate or cross several English local planning authority boundaries. Dividing a scheme into disconnected compounds does not automatically divide its biodiversity accounting.
NSIP biodiversity gain has its own boundary plan. Not every hectare inside the DCO order limits necessarily counts: land that will be unaffected can be identified separately, with evidence from an ecologist. Habitats affected by permanent or temporary works, and land used to deliver gains, must be dealt with properly. An attractive-looking site plan is not a substitute for that analysis.
Temporary working areas deserve particular attention. For qualifying low or very low distinctiveness habitats, reinstatement to the original type and condition within five years can avoid recording a permanent loss; for medium distinctiveness habitats the period is two years. Those affected habitats still belong in the baseline and boundary. This can materially influence cable routes, access tracks, compounds and the construction programme.
What happens to off-site land and long-term management?
Projects can provide biodiversity gains on site or through secured off-site habitat, with statutory biodiversity credits as a last-resort option. The off-site route creates a real land requirement, not simply a financial allowance. Habitat units must be appropriately allocated and recorded, and location can change their effective value through the metric’s spatial risk rules.
For landowners, NSIP biodiversity gain could create opportunities to provide long-term habitat, but obligations need careful scrutiny. Significant on-site gains or off-site gains must be secured and maintained for at least 30 years, through mechanisms such as a DCO requirement, conservation covenant or a section 106 obligation where appropriate. Management, monitoring, access and funding cannot safely be left unresolved.
Defra advises that where an NSIP operates beyond the 30-year minimum, habitat should continue to be maintained for at least the project’s operational life. The habitat management and monitoring plan must identify what happens, who is responsible and how compliance will be checked. An enforceable obligation today can therefore create practical responsibilities long after the construction team has left.
England’s boundary and the marine position
The mandatory regime applies to the English part of relevant infrastructure projects, including the intertidal area down to mean low water. It does not automatically extend to offshore marine habitat beyond that boundary. For cross-border schemes, Defra says the English baseline and statutory metric must use habitats in England, and gains counted towards the mandatory target must be delivered in England.
NSIP biodiversity gain therefore needs careful geographical treatment for electricity connections, ports and coastal infrastructure. A project may be subject to other marine, habitats or environmental assessment requirements outside the statutory BNG calculation. It would be misleading to suggest either that all offshore impacts are covered by this 10% requirement or that intertidal habitats are automatically outside it.
Defra described the objective in its August guidance announcement as protecting and restoring nature at scale
. That is a policy aspiration; the test for each application will be its evidenced habitat value, the deliverability of the gains and the legal arrangements by which those gains are secured.
What should planning professionals take from the change?
The immediate task is to check whether the project is caught by today’s application threshold, identify the correct biodiversity gain statement and test the actual working footprint against the statutory metric. That includes temporary land, off-site units, draft requirements and management responsibilities. The earlier these points affect design, the fewer expensive surprises should emerge at examination.
Planning Geek reported the forthcoming NSIP requirements in August, including the metric, spatial multipliers and securing mechanisms. Today’s development is that the previously announced date has arrived. Readers seeking the wider background can also consult our biodiversity net gain guide, while using the live Defra guidance for the specific DCO process.
NSIP biodiversity gain is now part of the application baseline for qualifying new projects in England. It does not constitute a grant of consent, a blanket exemption for infrastructure or proof that an individual scheme has achieved the required gain. Whether the project proceeds still depends on its full DCO case and the decision made under the applicable national infrastructure planning framework.
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