A Quick Guide to the New Biodiversity Net Gain Requirements for Developers

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New environment rules are now in place for property developers in England meaning planning permission will be conditional on improving a site’s biodiversity in almost all cases. Developers will need to be aware of the new biodiversity net gain (BNG) rules and make sure they have the right support to ensure they are following those rules correctly.

In this article, we cover the new rules and who they apply to, what approaches developers can take to meet biodiversity requirements and what may happen if developers fail to do so.

Need help with the legal aspects of a property development? Please contact Rachael Spalton who will be happy to advise.

Key points for developers to know

  • From 12 February 2024 (2 April 2024 for small sites) developers will normally need to deliver at least 10% biodiversity net gain in order to be granted planning permission
  • There are some exceptions including for developments below the threshold, some small housebuilder projects and qualifying self-build and custom build projects
  • Developers will need to have a BNG plan approved by the relevant planning authority and enter a legal agreement with the authority committing them to follow that plan
  • Developers must use the government’s statutory biodiversity metric tool to prove that they have met the requirement
  • BNG targets can be met through enhancing biodiversity on-site or at an off-site location
  • As a last resort, developers can meet BNG requirements through buying statutory biodiversity credits from the government
  • Developers must also strive to avoid loss of biodiverse habitat through their projects
  • If developers fail to meet their BNG requirements after planning is granted, they might be subject to enforcement action from their Local Planning Authority (LPA)

What is biodiversity net gain?

Biodiversity net gain (BNG) is an environmental concept that means biodiversity should be increased by a development project rather than decreased. This increase can be achieved in various ways, including by increasing biodiverse habitat at the development site or at a different, off-site location.

What are the new biodiversity net gain rules for developers?

Developers in England will need to deliver a measurable biodiversity net gain of 10% for all new development projects. This requirement is set out in the Environment Act 2021 and applies to most developments in England from 12 February 2024 and all developments from 2 April 2024 (with some limited exceptions).

While developers can achieve BNG by making improvements either on-site or off-site (or, as a last resort, by buying government BNG credits), a key point is that they must avoid loss of existing biodiverse habitat on a site wherever possible.

BNG habitats must be maintained for a minimum of 30 years. This requirement also applies to all on-site and off-site gains.  It should also be noted that local planning authorities could introduce policies which require BNG of more than 10%.

What types of developments do BNG rules apply to?

The new biodiversity net gain rules will apply to all new developments seeking planning permission, except for those that are exempt for one of the reasons set out below.

Small sites are exempt from the new rules until 2 April 2024. For residential developments, a small site is defined as one consisting of nine units or less, while for non-residential developments, a small site is one where the floor area being created is under 1000m² or where the site is less than one hectare.

There will be an ongoing exemption for ‘developments below the threshold’ which are defined as those that do not impact a priority habitat and that impact less than 25 square metres of habitat and less than 5 metres of ‘linear habitats’ (e.g. hedgerows).

There will also be an ongoing exemption for self-build and custom build projects comprising a maximum of nine dwellings on sites no larger than 0.5 hectares where all of the properties are self-build or custom build.

Finally, there will be exemptions available for small housebuilder projects, such as home extensions and loft conversions.

How can developers meet biodiversity net gain targets?

There are four key steps developers can take to achieve BNG requirements:

  1. Avoid or minimise any loss of existing biodiverse habitats on a development site.
  2. Add to or improve the biodiverse habitats on the development site.
  3. Enter an agreement with an off-site habitat gain provider to boost biodiversity elsewhere, creating a net gain of 10% across the two (or more) sites.
  4. Buy government BNG credits (this is intended as an option of last resort, with the credits priced at a level to discourage this approach as much as possible)

Developers will need to work with an appropriate ecologist to assess the existing biodiversity value of a site and to advise on suitable steps to boost the sites biodiversity. Based on this, the developers will need to provide a Biodiversity Net Gain (BNG) Plan showing how they will meet the requirements.

The Local Planning Authority (LPA) will then need to sign off on this plan in order for planning to be granted. The developer will sign a legal agreement with the authority detailing how this plan will be delivered, making the terms binding on the developer.

The government has provided a statutory biodiversity metric tool which must be used to assess the biodiversity of a site before and after a development in order to demonstrate the required 10% improvement has been achieved.

What happens if developers fail to meet their BNG obligations?

In the first instance, if a developer’s biodiversity net gain plan is not accepted by their Local Planning Authority, then planning permission is unlikely to be granted.

Where a developer has a BNG plan accepted and planning permission is granted, but the LPA considers that the finished development does not meet the BNG requirements, then enforcement action could be taken.

Enforcement action could include requiring the developer to undertake remediation work, making them buy costly government BNG credits or, in the most extreme cases, forcing a developer to modify or remove a development. Developers could also face fines for not correctly following an approved BNG plan.

How Longmores can help with biodiversity net gain planning requirements

With so many different issues to consider and an ever-changing regulatory landscape, having the right expert support can be critical for any development project.

At Longmores, our Commercial Property team are very experienced in dealing with both large and small scale property developments.

To discuss how we can help with the legal aspects of property development, please contact Rachael Spalton who will be happy to advise.

Please note the contents of this article are given for information only and must not be relied upon. Legal advice should always be sought in relation to specific circumstances.