Understanding how Biodiversity Net Gain (BNG) applies to Nationally Significant Infrastructure Projects (NSIPs) is becoming increasingly important for developers, consultants, and authorities shaping the UK’s future infrastructure. NSIPs include large-scale developments of national importance – such as energy, transport, water, and waste projects – that follow a different planning process to standard applications.
While BNG is already a legal requirement for most planning consents, it is set to apply to NSIPs from May 2026. This change means those delivering major infrastructure projects must begin planning now to integrate BNG principles into project design, land acquisition, and long-term management.
The Recent Consultation on BNG and NSIPs
In May 2025, the UK government launched a consultation on how BNG will apply to NSIPs. This consultation sets out the proposed approach and invites feedback from developers, local authorities, and others with an interest in major infrastructure. The consultation documents can be viewed here.
The government proposes that applicants will be required to submit a biodiversity gain plan and a completed biodiversity metric calculation to the Examining Authority as part of their Development Consent Order (DCO) application. These plans will need to meet minimum information requirements, but in many cases final details — such as the allocation of off-site gains or confirmation of credit purchases — may only be available after consent is granted. The consultation also recognises that design changes post-consent may affect BNG calculations, so plans must allow for a degree of flexibility.
How BNG Will Be Integrated into NSIPs
The government intends to align NSIPs with the biodiversity gain hierarchy, which prioritises on-site habitat creation and enhancement before off-site compensation or, as a last resort, the purchase of statutory biodiversity credits. However, developers will be able to deliver BNG on-site or off-site in the first instance, offering flexibility where large-scale developments make on-site delivery challenging.
Updates to the statutory biodiversity metric user guide are also proposed. These will clarify how the metric should be applied to NSIPs, including for projects that cross multiple local planning authority boundaries. Importantly, the consultation suggests that schemes spanning several authorities will be able to deliver off-site gains in any of the relevant areas without incurring additional spatial risk penalties.
The Legal and Planning Framework for NSIPs and BNG
NSIPs are governed by the Planning Act and require a DCO rather than standard planning permission. This process is overseen by the Planning Inspectorate and the relevant Secretary of State for the infrastructure sector involved. By integrating BNG into the DCO framework, the government aims to ensure that major infrastructure projects deliver measurable environmental benefits alongside essential services.
Challenges and Considerations for Developers
Applying BNG to NSIPs brings unique challenges due to the size and complexity of these projects. Many schemes cross multiple administrative boundaries, requiring coordination between different local authorities, statutory consultees, and landowners. Achieving a consistent approach to BNG delivery across these areas demands early engagement, clear ecological assessments, and carefully drafted legal agreements.
Additionally, irreplaceable habitats or complex ecosystems may require bespoke mitigation strategies beyond what the standard biodiversity metric can capture. The consultation acknowledges this and invites further input on how such challenges should be managed within the BNG framework for NSIPs.
Why Expert Support Matters
As the consultation process continues and guidance evolves, developers should seek expert advice early in the project lifecycle. At Civity, we help navigate the complexities of off-site BNG, from working with landowners to secure biodiversity units to ensuring compliance with the latest legal and planning requirements.
By engaging with the process now, developers can stay ahead of policy changes, minimise risk, and deliver infrastructure projects that contribute meaningfully to the UK’s environmental and sustainability goals.
Get in Touch
If you are involved in a nationally significant infrastructure project and want to understand how best to approach off-site BNG, contact Civity today at https://civitynge.com/ for expert advice and support tailored to your needs.
** The information in this blog is provided by Civity for general guidance and awareness around Biodiversity Net Gain (BNG) policy and practice in England. While we aim to ensure content is accurate and up to date at the time of publication, it should not be relied upon as legal advice or as a substitute for detailed planning or ecological consultancy input.
Civity does not provide legal services and cannot offer guarantees on planning decisions, BNG unit sales, or outcomes determined by Local Planning Authorities, Natural England, or Responsible Bodies.
Readers are encouraged to seek professional advice relevant to their specific circumstances, particularly in relation to legal agreements, land use planning, or habitat surveys.
