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Biodiversity Net Gain (BNG) is here: Why it’s important

The Topline

“Biodiversity Net Gain (BNG) is a new compulsory condition on planning permissions. Put plainly, BNG is one of the biggest changes to planning in over 30 years. It’s likely to affect over 100,000 planning applications every year. It’s an issue for all developers to grapple with.”

Josh Kitson, Director, Planning & Environment


An image of a calm pond under a blue sky, with reeds and trees. A visual metaphor for the topic of this post Biodiversity Net Gain (BNG).

Biodiversity Net Gain (BNG): What developers need to know

BNG seeks to ensure development has a positive impact on biodiversity – delivering a net gain when compared to the pre-development position. For applications from 12 February 2024, developers will be required to deliver a gain of 10%. [1]

Development sites will be scored according to a biodiversity metric.

Gains can be delivered: (i) on-site; (ii) off-site – on either land controlled by a developer or through the purchase of biodiversity units; or (iii) through the purchase of statutory credits.

It’s possible to combine all three options; however, developers are instructed to prioritise on-site, then off-site, with credits being the option of last resort.

The government is keen for the creation of a commercial market for biodiversity units. Land available for BNG should be placed on the biodiversity gain register.

The Biodiversity Unit Finder is a service for landowners and land managers with off-site biodiversity units, to link up with potential buyers.

The location of any off-site BNG will impact the calculation. Off-site gains in a neighbouring local planning authority (LPA) will be worth fewer biodiversity units than off-site gains in the same LPA as the development. Off-site gains beyond the neighbouring LPA will be worth even fewer.

The price for statutory credits has been set at a level which is intended to be unattractive. DEFRA has published indicative prices, ranging from £42,000 to £650,000. The range in prices is based on habitat type and distinctiveness.

Developers and planners should familiarise themselves with the draft biodiversity gain template and guidance for developers and local planning authorities.

A biodiversity gain plan will need to be approved by the LPA before commencing development. This will address how BNG will be delivered. Off-site land is likely to be bound by either a s106 agreement or a conservation covenant.

Careful thought will be needed when drafting these documents.

The government has recently published an amended version of the draft statutory instrument which outlines and expands how BNG will apply to different types of habitats.

Biodiversity Net Gain (BNG): How we can support you

Walker Morris’ Planning & Environment Team is a multi-disciplinary group of specialist lawyers experienced in all aspects of the environment and development agenda.

In relation to planning and project work, we guide clients from the purchase of land to the submission of planning applications, including advising on BNG requirements.

We also advise on environmental reports, prepare and co-ordinate environmental impact assessments, and help to manage teams of experts with different technical competences.

Please contact Josh Kitson or any member of the Planning & Environment Team for tailored advice, assistance or training on BNG, or development issues generally.

For more information, see our recent Habitat and Biodiversity Management video and watch out for our panel session at UKREiif 2024, which will focus on BNG.

Our team at UKREiiF

Are you navigating the complexities of Biodiversity Net Gain (BNG) in your development projects? We will be hosting a panel at UKREiiF which will focus, in particular, on biodiversity net gain (BNG) and its impact on developers.

This panel discussion offers practical insights and strategies to help you effectively address the new BNG requirements without compromising on the scale or quality of the development.

The panel will explore cost-effective approaches, proactive planning strategies, plus how to incorporate sustainability goals, environmental requirements, and sustainable value engineering into construction and supply chain contracts as well as discussion over how this issue is impacting land values.

Find out more about UKREiiF and our panel session here.


[1] BNG will be mandatory for major developments from 12 February 2024 and for minor sites from 2 April 2024. It’s expected to extend to Nationally Significant Infrastructure Projects from November 2025.

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