Illustrating flexible BNG for NSIPs: Interactive graphic, comparison and glossary

Alice Wibberley & Nancy Stuart 02 Nov 2026

Today marks the formal introduction of Biodiversity Net Gain (BNG) for Nationally Significant Infrastructure Projects (NSIPs) in England. All applicable applications for Development Consent Orders (DCO) made from today will need to demonstrate how the Biodiversity Objective will be met, with various information required at each stage of the consenting process.

Our previous blog reviewed the Government’s April 2026 response to consultation on how BNG should function for NSIPs. Since then: in June, Biodiversity Gain Statements were published for NSIPs both with and without a relevant national policy statement; and in August, DEFRA also published its guidance on the subject.

There has been some nervousness about how BNG requirements can be effectively brought forward as part of complex major infrastructure projects. Whilst there will be much to learn as the process embeds, there is now a wealth of guidance to facilitate the integration of BNG into the DCO regime, including important information on how flexibility can be preserved as complex NSIPs are brought forward. To unpack this further, we have produced an interactive graphic, comparison between the TCPA and NSIP processes, and a Glossary of key terms.

Addressing BNG in the consenting process

Our interactive graphic uses a hypothetical energy development at three key stages of the NSIP consenting process to illustrate how BNG may work in practice. It includes information requirements and where decisions need to be made in relation to BNG; and how the BNG Boundary could change over time with increasing design certainty.

Hover over each point in the graphic for more information, and see the Glossary for key terms.

Illustration by Deirdre van der Bank, interactive graphic by Mark Kilgallon

BNG in practice

To preserve flexibility, the BNG metric and strategy for delivering BNG is likely to be revised several times as a project is brought forward, but each development will be different. What is common is that the Biodiversity Objective must be met prior to the NSIP becoming operational, and several Updated Biodiversity Gain Plans may be required to verify final impacts and evidence the delivery of BNG.

BNG is only one part of the wider consenting process, but it is one that will require a coordinated and often strategic approach to prepare and submit the necessary information at each stage. There are significant opportunities to make use of the flexibility preserved in the process, but uncertainty regarding ecological impacts will need to be justified, and iterative results will need to be evidenced. Effective BNG will therefore rely on early alignment across the project team, with benefits from strategic oversight to understand interdependencies, manage uncertainty, and identify positive outcomes to support broader project success.

Comparison between TCPA and NSIPs

With the introduction of BNG for NSIPs now live, we have also put together a comparison of the key differences to be aware of from the TCPA BNG process and requirements.

	TCPA	NSIP
Legal Framework	BNG is required in England under a statutory framework introduced by Schedule 7A of the Town and Country Planning Act 1990 (inserted by the Environment Act 2021).	The statutory framework for mandatory BNG for NSIPs is introduced by Schedule 15 to the Environment Act 2021, which inserts Schedule 2A into the Planning Act 2008.
Applicable Guidance	The BNG Planning Practice Guidance, published by MHCLG, covers how BNG is applied through the planning process. This sits alongside a suite of BNG guidance published by Defra for developers, land managers and authorities.	The Defra BNG Guidance portal has been updated to include links for all NSIP related BNG Guidance. This includes: The BNG NSIP Guidance; The applicable Biodiversity Gain Statement for the relevant project/sector, which corresponds to the National Policy Statement of that project/sector; and Relisting links to guidance that applies to both TCPA and DCO applications. (such as on entering a legal agreement for BNG).
Application of the Biodiversity Gain Hierarchy	For planning applications the applicant must demonstrate how the Hierarchy has been followed, which for major applications prioritises first avoiding/mitigating impacts to onsite habitats; then onsite enhancements; new onsite habitats; offsite gains; and lastly purchase of credits.	For NSIP projects the use of onsite and offsite gains are treated equally, when the offsite gains are in the same LPA, National Character Area (NCA) or Marine Plan Area (MPA) boundary - for intertidal units.
Tools to use	The Statutory Metric or Small Sites Metric is to be used. The Defra Biodiversity Gain Site Register is used for Biodiversity Gains Sites and any offsite gains allocated to developments.	The same Statutory Metric and Gains Site Register is to be used for NSIPs. The small site metric will not be applicable.
Information requirements at application stage	Planning applications subject to the BNG condition must submit the following minimum information requirements: The completed metric for baseline and post-development; Description of any irreplaceable habitat within the application site boundary; Plan showing the location of any onsite habitat included in the biodiversity calculations and the location of any irreplaceable habitat.	DCO applicants must additionally submit: Statement of the ecologist’s role in the BNG strategy and documents; A BNG boundary plan; An Outline BGP (containing details stipulated within the relevant Biodiversity Gain Statement); Draft requirements to secure the BNG objective within the draft DCO; A draft HMMP for any significant onsite gains, along with a description of maintenance and monitoring of these; Description of any remaining uncertainty on the detailed design of the proposed development; Confirmation of the intended use of any excess onsite gains.
The consent and implementation	The Biodiversity Condition is deemed to apply to every planning permission granted for development of land in England (unless exemptions/transitional arrangements apply). Development cannot begin before a Biodiversity Gain Plan (BGP) has been submitted to and approved by the LPA. In the case of phased developments, an Overall BGP must first be approved and a Phase BGP must be approved prior to commencement of each phase.	The Secretary of State will not grant an application for development consent unless satisfied that the proposed development meets the biodiversity gain objective. Requirements must secure either an updated BGP or a phased BGP to be submitted and approved prior to commencement of (each phase of) development.
Discharging Authority	The LPA must state who the planning authority is for the purposes of the BGP within the decision notice.	The relevant discharging authority for the BNG Requirements must be stated in the draft DCO requirements. This could be the host LPA, a Lead LPA (for cross boundary projects), or the SoS. This should be discussed with PINS and the relevant LPAs prior to submission.
Size considerations	The main considerations of project scale within the TCPA BNG regime relate to small planning applications: Use of the small sites metric for non-major developments; The de minimis exemption to BNG; Exemption for sites with an area of 0.2 hectares or less.	Due to the typical large scale of NSIPs, the Guidance gives consideration to possible implications of scale and uncertainty in the following key ways: Use of a BNG boundary, which can be different to the Order Limits, and unaffected land can be excluded from the BNG boundary; Affecting land that is already secured for BNG for other developments; Considers addressing development that goes above or underneath habitats; Allows submissions with descriptions of remaining uncertainty.

Glossary

Click for our Glossary of key terms.

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