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The Environment Act 2021: Biodiversity Net Gain

What are the ‘Biodiversity Net Gain’ requirements for new developments introduced by the Environment Act 2021.

The introduction of the requirement to provide a 10% net gain of biodiversity for all new developments is as a response to the government’s goal to leave the environment in England in a better state than it is found over the next 25 years, as set out in their policy paper “A Green Future: Our 25 Year Plan to Improve the Environment”.

The consultation by DEFRA will consider how biodiversity net gain will work in practice and in particular cover:

  • the scope of the biodiversity net gain requirement for any new development;
  • the application of the biodiversity gain objective to different types of development; and
  • how the requirement will work for the current planning regime.

The consultation confirms that it is the government’s intention to apply the mandatory requirement for biodiversity net gain to be achieved for developments requiring planning permission under the Town and Country Planning 1990 will commence for new applications from November 2023.

What is Biodiversity Net Gain?

The new Environment Act 2021 introduced a requirement that any new planning application for development will be required to meet the objective that the “biodiversity value attributable to the development exceeds the pre-development biodiversity value of the on-site habitat by at least [10%]”.

The ‘biodiversity value’ is attributed by looking at the post-development on-site habitat, off-site biodiversity gain allocated to the development, and any biodiversity credits purchased for the development.  Developers will be required to demonstrate that they will deliver a minimum 10% net gain of biodiversity units for ‘area-based’ habitats and any relevant linear habitats, such as hedgerows, lines of trees, and watercourses.

The purpose of this new requirement is to counteract the loss or degradation of habitat caused by the proposed development.

The biodiversity value will need to be secured for a minimum duration of 30 years.

How will the net gain be achieved?

‘Biodiversity value’ can be achieved by:

  • the creation of post-development on-site habitat;
  • Having registered off-site biodiversity gain allocated to the development; and
  • Obtain statutory biodiversity credits from the Secretary of State to meet the biodiversity gain objective.

The Government will keep a register of off-site biodiversity gain sites.  Registered sites can be land where a conservation covenant or planning obligation to carry out works for the purpose of habitat enhancement and thereafter be maintained for at least 30 years after the completion of those works.  Please see our separate article on conservation covenants (below) for further details on those requirements also introduced by the Environment Act.

A developer may purchase statutory biodiversity credits from the Secretary of State to meet the biodiversity gain objective.  Credits are intended to be sold at a value over market value to encourage local biodiversity schemes.  The Secretary of State must apply payments received for the purpose of habitat enhancement only, which will include purchasing interests in land, carry out works, and associated operational and administration costs.

What is required when making an application for planning?

A plan for how the development will achieve the creation of a 10% increase in biodiversity value will need to be submitted to the planning authority for approval prior to commencement of the development.  The plan will need to include information on the steps to be taken to minimise the impact of the development on biodiversity, providing details of the existing pre-development and intended post-development biodiversity value of the on-site habitat, any registered off-site biodiversity gain allocated to the development and the gain in biodiversity value that provides, and any biodiversity credits purchased for the development from the Government.

The biodiversity value will be calculated used a ‘biodiversity metric’ produced by the Secretary of State measuring the biodiversity value or relative biodiversity value of habitat or habitat enhancement.  The biodiversity metric has not been produced yet but will be measured in ‘biodiversity units’ by taking account of the type, extent and condition of habitats allocated to the development site.

The intention is that the delivery of the biodiversity net gain will follow a hierarchy whereby the aim will be to, first, avoid or reduce biodiversity impacts through site selection and layout; second, enhance and restore biodiversity on-site; third, create or enhance off-site habitats either on their own land or by purchasing biodiversity units on the market; and finally, as a last resort, purchase statutory biodiversity credits only where it can be demonstrated that biodiversity net gain would not be achieved through the available on-site and off-site options.

The legislation confirms that anyone applying for planning permission will need to measure the pre-development biodiversity value of any on-site habitat, which will be taken at the date of the relevant application, or otherwise at the date of grant of a planning permission.  A different date can be agreed between the applicant and the planning authority, if required.

The post-development biodiversity value of the on-site habitat will be calculated as the projected value of the on-site habitat as at the time the development is completed.  This is assessed by calculating the increase (or decrease) between the pre- and post- development biodiversity values.

The biodiversity gain objective will only be met if the biodiversity value attributable to the development exceeds the pre-development biodiversity value by at least 10%. The 10% requirement can be amended by regulations in the future.

It is also worth noting that where a development would result in the loss of irreplaceable habitat then this will fall outside of the biodiversity metric calculation for the development, and it will have its own bespoke compensation agreed with the planning authority for the irreplaceable area.  The government will set out a list of irreplaceable habitats in secondary legislation, which is yet to be confirmed.

Will all developments caught by the requirement?

The requirement to show how 10% biodiversity gain is to be achieved will be a condition which is to be for planning permissions granted in England and also planning consents for nationally significant infrastructure projects.

However, the requirement will not apply to planning permissions granted by a development order including under the General Permitted Development Order and in respect of any urgent Crown development.

The consultation also proposes that an exemption from the requirement to provide the biodiversity net gain for:

  • development proposals which result in negligible impacts or minimal impacts to low or medium ‘distinctiveness’ habitats such as agriculturally productive land;
  • householder applications; and
  • change of use applications.

The consultation is considering if exemptions should also be made for the creation of biodiversity gain sites, self-builds and custom housebuilding.

Under the consultation, brownfield sites, temporary permissions and permitted developments will be caught by the biodiversity gain requirement.

If you want to respond to the consultation please following this link:

FSP’s expertise

The Agricultural & Rural Property team has a wealth of experience in dealing with all issues relating to development of land and so if you are considering selling or buying land for development, please contact Hazel Eccles for further information on what help we can offer you.