Government publishes BNG framework for NSIPs
Defra has this week published a suite of guidance and policy documents setting out how Biodiversity Net Gain (BNG) will be implemented for Nationally Significant Infrastructure Projects (NSIPs) in England from 2 November 2026.
The publications provide long-awaited detail on how the mandatory 10% BNG requirement will apply to major infrastructure projects requiring Development Consent Orders (DCOs), including energy infrastructure, airports, ports, water resources, wastewater projects, national networks, data centres, geological disposal facilities and projects where no National Policy Statement applies.
The new framework follows the Government’s response to last year’s consultation on NSIP BNG and marks a significant step towards extending biodiversity net gain requirements beyond the town and country planning regime introduced in 2024.
The package includes:
- Biodiversity Gain Statements for each NSIP sector, setting out how projects must calculate, deliver and report biodiversity net gain.
- New guidance on establishing BNG baselines for NSIPs.
- Updated guidance on what measures can count towards BNG delivery.
- Supporting guidance on legal agreements, habitat management and monitoring plans, biodiversity gain sites and statutory biodiversity credits.
Together, these documents provide the operational framework that developers, ecological consultants, competent authorities and infrastructure promoters will need to follow ahead of implementation in November.
A central element of the new guidance is clarification on how NSIP baseline biodiversity value should be calculated. The guidance confirms that baseline calculations must include habitats within the development boundary that will be negatively affected by the project, whether impacts are temporary or permanent, as well as habitats that will contribute towards achieving biodiversity net gain.
The guidance also recognises the complexities associated with large infrastructure schemes where final construction footprints may not yet be fully defined at the point of application, providing additional direction on how baseline assessments should be undertaken where project design details remain uncertain.
As with other forms of development subject to mandatory BNG, NSIPs will be expected to follow the mitigation hierarchy, secure gains through on-site and off-site habitat creation and enhancement where possible, and use statutory biodiversity credits only as a last resort.