BNG: Changes on the horizon

In a flurry of activity, Defra has published the Government’s response to two consultations on Biodiversity Net Gain (“BNG”) as well as launching a further consultation on proposals for a targeted exemption for residential development on brownfield land.

Proposals for reform to the BNG system form part of the Government’s wider ambitions for reform of the development management system to unlock residential development across the country.

Smaller scale development

In responding to the consultation on improving the implementation of biodiversity net gain for minor, medium and brownfield development, the Government has proposed a raft of changes to the system including:

• a new exemption for all development with a site area of 0.2 hectares or less;

• the removal of the existing exemption for self-build and custom build development; and

• the creation of further new exemptions for development whose primary objective is to conserve or enhance biodiversity; temporary planning permissions covering permissions granted for a maximum of five years; and development enhancing parks, playing fields and public gardens.

Consideration is also being given to changes to the statutory biodiversity metric and for minor development. Changes will be made to the biodiversity gain hierarchy to put onsite and offsite gains on an equal footing, preventing developers of minor developments being forced into delivering inappropriate onsite gains or becoming locked into disagreements with local planning authorities as to the application of the hierarchy.

The connection between the spatial multiplier and LPA boundaries and National Character Area boundaries is also being removed, with the spatial multiplier instead aligning with local nature recovery area strategies. One impact of this will be to allow developers to seek off-site units from a wider area, without being penalised by the spatial multiplier.

There is a staggered implementation timetable planned with some changes to potentially come into effect as early as 31 July 2026.

NSIPs and BNG requirements

In its consultation response, the Government has confirmed that the requirement to deliver BNG in connection with development of NSIPs will be implemented in November 2026.

In responding on the practical aspects of delivering BNG alongside these schemes, it has been confirmed, amongst other things, that:

• a consistent BNG requirement will be applied across all NSIP types without exemptions or voluntary approaches;

• NSIPs must use the statutory biodiversity metric;

• the requirements will differentiate between the limits of an Order and a “BNG boundary”, with anything included within the BNG boundary forming the “on-site” habitat;

• significant on-site gains will be required to be maintained for at least 30-yerars from the completion of the habitat creation or enhancement works (to be secured by the DCO, a planning obligation or conservation covenant), with an expectation that where the lifespan of the project is greater than 30 years, the habitat should be maintained for the lifespan of the project;

• off-site gains can be allocated to NSIP development from within any local planning authority (LPA), National Character Area (NCA) or Marine Plan Areas the NSIP BNG boundary is located within, which will give provide significant flexibility, particularly in the case of substantial linear schemes; and

• there will be special provisions within the metric allowing for the assessment of temporary impacts, with an extended restoration period of five years for habitats of low and very low distinctiveness.

There remains a significant amount of further detail to be resolved before the “go live” date in November 2026 and Defra has committed to work with stakeholders to ensure that the requirements are clear. It has also committed to work with the Planning Inspectorate and LPAs to support preparations for the mandatory BNG for NSIPs regime.

A target exemption for residential development on brownfield sites?

To support its view that brownfield land should be the first port of call for development, the Government has launched a consultation on proposals to exempt residential development on brownfield sites from BNG requirements.

The consultation explores a number of key principles including:

• the appropriate definition of “brownfield development”;

• the appropriate site size below which a brownfield development site would be exempt from delivering BNG; and

• whether any additional measures are needed to ensure the exemption is appropriately targeted in relation to potential ecological impacts.

The consultation runs until 10 June, with respondents free to provide responses to all or some of the questions raised, as they feel appropriate.

In conclusion…

It is clear that 2026 will see the most significant changes to the BNG system since it was introduced. Stakeholders will need to keep a close eye on announcements and new legislation as they come forward. Should you require any advice on any aspect of BNG, please contact Edward Long, Alistair Taylor, Nicola Gooch or another member of the  Planning and Environmental Team.