Government confirms Biodiversity Net Gain for major infrastructure from November 2026

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The UK Government has confirmed that Biodiversity Net Gain (BNG) will apply to Nationally Significant Infrastructure Projects (NSIPs) from November 2026, following publication of its response to the Biodiversity net gain for nationally significant infrastructure projects: summary of responses and government response consultation.

This marks an important step forward for the integration of nature into major infrastructure planning and provides much-needed clarity after a period of uncertainty. The confirmed implementation date gives developers, local authorities and ecologists time to prepare for the extension of BNG into the NSIP regime.

A consistent national approach

The Government has confirmed that a mandatory 10% BNG requirement will apply across all NSIP types, with no exemptions or voluntary approaches. This aligns with the existing regime under the Town and Country Planning Act 1990 biodiversity net gain provisions, helping to ensure consistency, simplicity and fairness across sectors while supporting a coherent national framework for nature recovery.

Defining the BNG boundary

A key clarification relates to how the BNG baseline will be defined. Following stakeholder feedback, Defra has decided that unimpacted habitats within the Order limits will not need to be included in the baseline. Instead, the 10% requirement will apply to a defined “BNG boundary”, which includes habitats that are:

  • negatively impacted by the development (temporarily or permanently), and/or
  • used to deliver biodiversity gains.

Applicants will be required to submit a BNG boundary plan as part of their outline biodiversity gain plan, improving transparency and consistency in how projects assess impacts and deliver gains.

Temporary impacts and delivery flexibility

The Government has confirmed that the 10% BNG requirement will also apply to land that is only temporarily affected by development. As with other BNG developments, gains can be delivered on-site, off-site, or via statutory biodiversity credits as a last resort.

The existing biodiversity metric will continue to allow flexibility in exceptional ecological circumstances (including use of “habitat created in advance”), with Defra reviewing guidance to ensure these provisions are clear and workable for NSIPs.

Guidance, monitoring and local authority support

Defra has acknowledged the strong demand for clear and practical guidance and has committed to publishing priority guidance in 2026, with further material to follow. This will cover key areas such as:

  • preparation of biodiversity gain plans
  • monitoring and enforcement
  • adaptive management over the required 30-year period

The Government has also reiterated the importance of robust monitoring, with all significant on-site and off-site gains required to be secured and maintained for at least 30 years.

Local Planning Authorities will continue to receive new burdens funding (currently allocated through to 2026-27), with further review allowed for to ensure that they are adequately resourced for their role in NSIPs.

Interaction with other frameworks

Defra recognises the need for clarity on how BNG will interact with other policy frameworks, including the emerging Nature Restoration Fund (NRF). Further information will be provided as these policies develop to support joined-up delivery.

A positive step for nature and practice

The above confirmation of BNG for NSIPs provides much needed clarity and certainty and should help to stabilise and strengthen the regime moving forward and delivery nature recovery at scale.