The Government’s BNG consultations explained (and why you should care)

Anna Maw 12 Jun 2025

The BNG system has an important role to play in improving and enhancing natural habitats, and ensuring development has a measurably positive impact.[1] The statutory Biodiversity Net Gain (‘BNG’) requirement came into force in the English planning system in February 2024, seeking to ensure that habitats for wildlife are left in a measurably better state than they were before development took place. As a result, it is now mandatory under Schedule 7a of the Town and Country Planning Act 1990 for relevant developments to deliver a 10% BNG on the value of all habitats within their redline boundary (known as the ‘biodiversity baseline’).

16 months on from the introduction of the mandatory BNG requirement and we’ve learned how to navigate the statutory biodiversity metric, appreciated the delivery of on- and off-site compensation, and rolled with the punches of varying validation requirements. We’re also starting to see the discharge of BNG planning conditions from the first wave of mandatory BNG developments.[2]

On 28 May 2025, the government launched two consultations relating to BNG, giving stakeholders the opportunity to suggest how the existing system could be improved, and how BNG could apply to major infrastructure schemes:

Improving the implementation of biodiversity net gain for minor, medium and brownfield development; and
Biodiversity Net Gain for Nationally Significant Infrastructure Projects (‘NSIPs’) (which have to date been exempt).

A comprehensive understanding of the proposed changes, and proactive engagement with the consultation is vital, as feedback will contribute towards improving the overall BNG approach, streamlining the delivery of development in turn.

To assist, we have summarised the key proposals and provided our initial thoughts on the two consultations.

Whistle-Stop Guide to the BNG Consultations

Consultation 1 - Improving the implementation of biodiversity of net gain for minor, medium and brownfield development[3]

This consultation seeks views on options to improve the implementation of BNG for relevant developments including extending exemptions, simplifying the small sites metric and easing access to the off-site market.

The key proposals upon which views are sought are outlined below under topic headings.

Exemptions:

Replacing the custom build/self-build exemption with a single-dwelling exemption;
Increasing the de minimis exemption from 25 sqm of affected habitat to 50, 100, 200 (or some other figure);
Exempting all but major development (i.e. the pre-2 April 2024 situation); and
Introducing a new exemption for temporary development granted for up to 5 years.

Minor developments:

Relaxation of the biodiversity gain hierarchy so that offsite and onsite biodiversity gains are treated equally;
Removing the distance penalty for offsite compensation (the spatial risk multiplier);
Relaxation of the trading rules for some minor development;
Giving local authorities discretion to disapply the requirement to deliver BNG for watercourses under specified circumstances.

Other:

Updated definition of Open Mosaic Habitats and ability to use alternative compensation arrangements;
Several proposed changes to the Small Sites Metric; and
Increasing the distance whereby no penalty is applied to offsite compensation.

Consultation 2 - Biodiversity Net Gain for Nationally Significant Infrastructure Projects[4]

This consultation seeks views on the implementation of BNG for NSIPs.

The Government propose that NSIP schemes deliver a 10% BNG from May 2025, and the consultation provides draft model text for core ‘biodiversity gains statements’ that will be applied to each NSIP sector. Biodiversity gain statements will set out the biodiversity gain objectives for each NSIP type, and eventually be incorporated into the relevant National Policy Statements (‘NPS’).

To ensure proportionality and consistency, BNG will be implemented for all onshore NSIP sectors, and will apply to any temporary, permanent and associated development included within the DCO site boundary (‘order limits’). Marine NSIPs beyond the intertidal zone are not currently included within the scope of the mandatory requirements for BNG.

The consultation suggests the following:

Evidence required for submission and decision making:

Under the proposed NSIP scheme, a Biodiversity Gain Plan (BGP) demonstrating how BNG will be delivered and a completed biodiversity metric calculation must be submitted with the application, rather than at the post-consent stage, although there will be an ability to update and finalise BGPs post consent.

Calculating BNG:

NSIPs must use the statutory biodiversity metric to calculate biodiversity value for the purposes of biodiversity net gain.
The statutory biodiversity metric user guide will be updated ahead of BNG becoming mandatory for NSIPs, to provide additional details on how the metric can be applied for NSIPs.

Delivering BNG:

Delivering BNG for NSIPs will differ from BNG for development granted permission under the TCPA 1990. Applicants will be able to deliver BNG on-site or off-site in the first instance, and by purchasing statutory biodiversity credits as a last resort.

Reflection on the consultation

Lichfields welcome the consultations, which demonstrate the government’s commitment to finding a pragmatic way forwards to striking an appropriate balance between delivering development and enhancing biodiversity. The introduction of the statutory BNG requirement has been a big change for the planning system and has, inevitably led to some significant challenges, particularly on smaller projects and on some brownfield sites. We believe the consultation represents a positive step forwards in addressing some of these challenges whilst not losing focus of the need to deliver meaningful gains in biodiversity.

We are pleased to see the BNG for NSIP consultation, having waited some time for this guidance to be released. It provides some clarity on how BNG will work in relation to NSIP development, with some key differences to the system operating for developments subject to planning permission.

How we can help

Lichfields’ specialist in-house BNG team have been busy scrutinising the consultations and are able to assist with making representations.

If you have any queries regarding the new government consultations, or navigating the BNG system more generally, please get in touch. We look forward to working with our clients at this stage in the process and hearing your thoughts on the consultations.

Both consultations close at 11:59pm on 24 July 2025.

Footnotes

[1] Department for Environment, Food & Rural Affairs (2025) Biodiversity net gain for nationally significant infrastructure projects. Available at: https://www.gov.uk/government/consultations/biodiversity-net-gain-for-nationally-significant-infrastructure-projects

[2] Overhead, H (2025) As BNG turns 1 is the system toddling forwards or still giving us sleepless nights? Available at: https://lichfields.uk/blog/2025/february/12/as-bng-turns-1-is-the-system-toddling-forwards-or-still-giving-us-sleepless-nights

[3] Department for Environment, Food & Rural Affairs (2025) Improving the implementation of biodiversity net gain for minor, medium and brownfield development. Available at: https://www.gov.uk/government/consultations/improving-the-implementation-of-biodiversity-net-gain-for-minor-medium-and-brownfield-development

[4] Department for Environment, Food & Rural Affairs (2025) Biodiversity net gain for nationally significant infrastructure projects. Available at: https://www.gov.uk/government/consultations/biodiversity-net-gain-for-nationally-significant-infrastructure-projects

Planning matters