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Biodiversity Net Gain Now in Force – What Does It Mean for You?



The UK has significantly advanced by implementing Mandatory Biodiversity Net Gain (BNG) in the ongoing effort to balance development with conservation.

As this transformative policy and additional guidance emerge, it demonstrates a strong commitment to preserving and enhancing our natural heritage for future generations.

On February 12, 2024, the mandatory requirement for developers to provide BNG became effective.

All new developments must now deliver a net gain in biodiversity, ensuring that measurable improvements in habitat quality and quantity offset any ecological damage caused during construction.

What Does It Mean?

Developers must submit a biodiversity gain plan by the day after planning permission is granted. The local authority will only approve this plan if it outlines a strategy for achieving a 10% biodiversity gain objective.

This objective mandates a minimum 10% increase in post-development biodiversity value compared to the pre-development biodiversity value of the site for which planning permission is granted.

Which Planning Applications Will It Apply To?

BNG applies to planning permissions granted for applications submitted on or after February 12, 2024. Permissions granted for applications made before this date are not subject to the biodiversity net gain requirement.

The mandatory BNG provisions will apply to all planning applications for ‘major development,’ including:

  • The provision of more than ten dwelling houses or, if the number of dwellings is unknown, development on a site larger than 0.5 hectares.
  • The development involves the construction of a building or buildings with a total floor area of 1,000 square meters or more.
  • Development is carried out on a site of 1 hectare or more.

Starting April 1, 2024, the requirements will also apply to ‘small sites,’ using a different metric to ensure the BNG calculations are proportional to the development.

How Is BNG Secured?

The habitat enhancements must be secured through an appropriate mechanism and maintained for at least 30 years after the development.

The local planning authority must be satisfied that the BNG will be delivered. This can be secured via (i) a planning condition, (ii) a planning obligation, or (iii) a conservation covenant (a new statutory scheme under the Environment Act 2021).

The local planning authority is responsible for overseeing the delivery of the BNG and taking enforcement action if commitments are not fulfilled.

Biodiversity Gain Plan

The new BNG condition requires the local planning authority to submit and approve a biodiversity gain plan before any development can legally commence.

This plan should include assessing the value of the natural habitats onsite, both pre-development and post-development, ensuring at least a 10% BNG.

The biodiversity gain plan must include the following:

  • Information about minimising adverse effects of development on onsite and other habitats’ biodiversity;
  • The pre-development and post-development biodiversity value of the onsite habitat;
  • Any registered offsite biodiversity gain units allocated to the development and the biodiversity value of that gain to the development;
  • Any statutory biodiversity credits purchased for the development.

Developers are encouraged to follow a hierarchy of mitigation measures to avoid, minimise, restore, and offset impacts on biodiversity.

Avoiding or minimising impacts on biodiversity should be prioritised. In some cases, achieving BNG on the development site may be challenging.

Biodiversity offsetting allows developers to compensate for a site’s habitat value, provided they pay to restore another habitat site that has the potential to reach at least the same quality as the habitat that will be lost.

Developers can meet the biodiversity requirement by creating offsite biodiversity habitats by accessing additional land.

Finally, where BNG cannot be delivered onsite or offsite, the impacts on biodiversity can be offset through the purchase of biodiversity credits.

While implementing BNG may present challenges, including upfront costs and regulatory complexities, the long-term benefits far outweigh the initial investment.

BNG’s success relies on collaboration and engagement across various sectors.

Developers, planners, ecologists, and policymakers must work together to ensure that biodiversity gains are accurately quantified, monitored, and maintained over time.

By Emily Sutherland, Senior Associate in our Commercial Property Law Team

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