BNG for NSIPs: A quick overview

The government has published its response to its 2025 consultation on the implementation of mandatory Biodiversity Net Gain (BNG) for Nationally Significant Infrastructure Projects (NSIPs).

BNG for NSIPs: Essentials and resources

BNG is now scheduled to apply to NSIP applications from 2 November 2026. Promoters and other stakeholders involved in infrastructure projects [1] now have a defined pathway to prepare.

From 2 November this year, NSIPs will be subject to a biodiversity gain statement, which will play a central role in both the examination of applications and the Secretary of State’s decision‑making. The statement will be incorporated into the relevant National Policy Statement or will form a standalone statement where there is no applicable NPS. The statement will:

• define the biodiversity gain objective (at least 10% net gain)
• set out how biodiversity value must be calculated
• explain how gains are demonstrated and verified.

The biodiversity gain objective:

• applies only to NSIPs, or components of NSIPs, in England;
• applies up to the mean low‑water mark, including the intertidal zone; and
• doesn’t apply to works in the marine environment beyond the intertidal zone.

The DCO application must then meet the biodiversity gain objective set out in the relevant biodiversity gain statement. In practice, this introduces a new mandatory hurdle within the Development Consent Order (DCO) process.

For cross‑border projects, this means that BNG calculations and delivery will need to be aligned specifically to English components of the scheme.

Under the new approach, BNG will be calculated in relation only to the land that will be negatively impacted by the development through the temporary or permanent deterioration or loss of habitats. That means land not subject to any proposed works won’t need to be included in the BNG baseline calculation. This will be particularly helpful for projects where a wider area is included within the DCO application than is actually required for works.

Unlike the more general BNG regime (for applications under the Town and Country Planning Act 1990) which favours on-site BNG provision, the NSIP regime allows on-site or off-site BNG delivery without a policy weighting in favour of either (subject to application of the spatial risk multiplier for NSIPs).

It’s worth noting, BNG for NSIPs won’t apply retrospectively. Post-consent changes to DCOs won’t trigger mandatory BNG where the original DCO application was made before 2 November 2026.

Biodiversity gain statements for NSIPs

On 2 June 2026, Defra published a suite of biodiversity gain statements (BGS) for NSIPs across the infrastructure and energy sector, including developments where no national policy statement has effect. The statements act as interim, cross-sector policy guidance ensuring that all NSIPs consistently deliver measurable biodiversity net gain, especially where national policy statements are silent, outdated, or absent.

Each BGS tailors its emphasis to the characteristics of different infrastructure types. For example (non-exhaustively):

• The energy infrastructure (e.g. solar, wind, generating stations) BGS addresses large land-take and habitat change, often in rural areas. It recognises opportunities for dual-use land (e.g. solar farms with habitat creation) and encourages on-site habitat enhancement. It acknowledges temporary vs permanent impacts (such as construction vs operation) and seeks to balance biodiversity with energy security and net zero objectives.
• The national networks (roads, rail, pipelines, cables) BGS deals with fragmentation of habitats over long corridors. It emphasises connectivity and ecological corridors, avoiding severance of habitats. It recognises practical difficulty of delivering all gains on-site, so places greater reliance on strategic off-site compensation. It also encourages landscape-scale planning.
• The water and waste infrastructure BGSs address projects with direct impacts on aquatic ecosystems. They focus on rivers, wetlands, and water quality.
• The data centre BGS follows the government’s model text for NSIPs, but its application is tailored to large, often campus‑style digital infrastructure schemes, ensuring data centre development contributes to nature recovery alongside economic/digital infrastructure delivery.

BNG for NSIPs: Requirements and early action

Applicants will be required to submit an outline biodiversity gain plan as part of their DCO application to the Planning Inspectorate. A BNG Boundary Plan must be provided alongside the outline biodiversity gain plan. It should show the entire DCO limits, overlay the BNG boundary within it, and delineate areas that will be negatively impacted, areas that provide BNG, and unimpacted habitat that’s both included in the BNG boundary and excluded from the BNG boundary and baseline. The outline plan must set out the applicant’s strategy for achieving BNG of at least 10%, and how gains will be calculated, secured and managed over the long term. Significant on-site habitat and offsite gains are to be maintained for a period of 30 years and there should be basic maintenance of on-site habitat for the lifetime of the NSIP.

An updated or phased Biodiversity Gain Plan will be required for approval prior to the commencement of development (or each phase of development).

While detailed delivery mechanisms may be finalised post‑consent, the required outline biodiversity gain plan means that BNG will need to be embedded early in project design, land referencing and environmental assessment work.

For developers, early engagement with ecological advisors, landowners and supply chains for off‑site biodiversity gain units will be essential to avoid later delays or constraints at examination.

For landowners, the NSIP BNG regime may present opportunities to host on- or off‑site habitat creation linked to major projects. The long‑term management and legal securing of habitats will, however, require careful structuring through appropriate agreements and governance arrangements.

Any business involved in NSIPs should use the period between now and November to review project pipelines and ensure that BNG is factored into commercial, land and consenting strategies.

How we can help

Our cross-discipline Planning and Infrastructure & Energy specialists are experienced and expert in advising clients in relation to the NSIP BNG regime. Please contact Lee for further information.

[1] including in-scope nuclear projects. Nuclear power projects in England and Wales with a capacity over 50MW (or 350MW in Wales) are classified as NSIPs and the Nuclear Regulatory Taskforce’s recommendation 18 relates to BNG reform.