What is BNG?
BNG (Biodiversity Net Gain) is a government strategy to ensure that natural habitats are protected and left in a measurably better condition after development takes place. In England, BNG is mandatory for new developments under Schedule 7A of the Town and Country Planning Act 1990 (as inserted by Schedule 14 of the Environment Act 2021) Under this Schedule, developers must deliver a BNG of at least 10% meaning that the development will result in more or better quality natural habitats than were present prior to the development.
How is BNG measured?
BNG is measured by establishing biodiversity units of a site pre-development based on the size, quality, location and type using a statutory biodiversity metric. These units can be lost or generated through development and work to the site in question and developers are required to calculate how many additional units are required in order to replace any units of habitat lost and to achieve the required 10% BNG.
Who is impacted by BNG?
BNG affects developers of both major developments and smaller sites and also, local planning authorities and land owners/land managers looking to sell land for development or take advantage of off-site BNG options.
From November 2025, nationally significant infrastructure developments will also be caught by the legislation.
Are there any exemptions to the BNG obligations?
In some circumstances developments are exempt from BNG including:
- Developments where planning applications were made before 12 February 2024;
- Development which decrease the biodiversity value by less than: 25 square metres for on-site or5 metres for on-site linear habitats such as hedgerows.
- Some householder applications;
- Some self-build or custom build applications;
- Developments forming part or ancillary to the High Speed Rail Transport Network.
How does BNG impact developers?
As BNG is a statutory requirement, developers must deliver 10% BNG on all new developments therefore, it is now a key consideration when assessing the viability of a site, arranging site set-up and costing proposed developments. It is important to consider how best to achieve BNG on or off-site and the best approach to documenting BNG provisions into all land sale or lease agreements and obligations into planning agreements to ensure the parties are adequately protected and able to fulfil their BNG obligations.
Developers must also consider that for significant on-site or off-site gains, the new or enhanced habitats must be maintained for a minimum of 30 years and this is likely to form part of a planning agreement with the LPA.
How can BNG be achieved?
BNG can be achieved by either:
- creating biodiversity onsite;
- through a mixture of on-site and off-site BNG, by either making off-site biodiversity gains on land they already own or by buying biodiversity units from third party land owners; or
- as a last resort, if BNG cannot be achieved through on-site or off-site gains, developers must buy statutory biodiversity credits from the government.
What should land owners be aware of when selling on the BNG market?
Selling land on the BNG market in a potential source of revenue for land owners (the government estimated that this market is expected to be worth £135m-£274m annually) but they would need to register the land on the national biodiversity gain sites register and record the units with a responsible body or LPA and your obligations relating to the BNG through a legal agreement, before selling the units.
The agreement would set out how the land owner/manager will create and nurture the biodiversity of their units and monitor the same and must last for a minimum of 30 years.
Once BNG units are sold, the parties need to apply to record this allocation on the register. The land owner should consider who should be responsible for registering the allocation and whether they should be passing on the obligations they have signed up to when registering the BNG units and document this accordingly.
DWF is hosting a BNG dinner and discussion on Monday 19th May 2025, in Leeds as part of our UKREiiF programme. We will be addressing various practical challenges, approaches and solutions that have been adopted, as well as identifying where simplification and improvement may be achieved.
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