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Biodiversity gain plans and satisfying the biodiversity gain objective

New standards mean developers must deliver a biodiversity net gain of at least 10% for projects to commence

"Meeting the biodiversity gain objective requires the development's biodiversity value to exceed the site's pre-development biodiversity value by at least 10%."

Amendments by the Environment Act 2021 (EA 2021) to the Town and Country Planning Act 1990 (TCPA) have introduced a deemed planning condition for most developments granted planning permission after the relevant provisions come into force (anticipated to be November 2023). The effect of this is that, before such development can commence, the developer must demonstrate that the scheme will deliver biodiversity net gain of at least 10% which will be maintained for 30 years or more.

How can the condition be met so that development can commence?

Submitting a biodiversity gain plan

Prior to the commencement of development, the developer must submit a "biodiversity gain plan" to the relevant planning authority. Development cannot commence until the planning authority has approved the plan.

The planning authority may only approve the biodiversity gain plan if it evidences that the "biodiversity gain objective" is met.

The biodiversity gain objective will only be met if the biodiversity value attributable to the development exceeds the pre-development biodiversity value of the onsite habitat by at least 10%.

What is a biodiversity gain plan?

A biodiversity gain plan is a plan relating to the development for which planning permission is granted which specifies:

  • Information about the steps taken / to be taken to minimise the adverse effect the development on the biodiversity of the onsite habitat and any other habitat; 
  • the pre-development biodiversity value of the onsite habitat;
  • the post-development biodiversity value of the onsite habitat;
  • any registered offsite biodiversity gain allocated to the development and the biodiversity value of that gain in relation to the development;
  • and any biodiversity credits purchased for the development; and
  • such other matters as the Secretary of State may by regulations specify.

What is the "pre-development biodiversity value of the onsite habitat"?

This is the biodiversity value of the onsite habitat on the date on which the application was made. This must be calculated in accordance with the biodiversity metric, which is a habitat based approach used to assess an area’s value to wildlife by using the habitat features to calculate biodiversity value. The current version of the biodiversity metric is Natural England's biodiversity metric 3.0.

To prevent a landowner purposefully reducing the pre-development biodiversity value, where activities on land are carried out on or after 30 January 2020 which have the effect of lowering the biodiversity value onsite otherwise than in accordance with a planning permission, the pre-development biodiversity value of the onsite habitat is the value prior to those activities being undertaken.

What is the "post-development biodiversity value of the onsite habitat"?

This is the projected value of the onsite habitat at the time the development is completed, also calculated in accordance with the biodiversity metric.

Where this is 10% or more than the pre-development biodiversity value of the onsite habitat, nothing further is required to satisfy the biodiversity gain objective and discharge the condition.

For proposed increases to the onsite biodiversity value to be taken into account when calculating the post development biodiversity value, any habitat enhancement must be required to be maintained for a period of at least 30 years after the development is completed. This may be secured via a condition of the planning permission, a planning obligation pursuant to section 106 of the TCPA 1990 or a conservation covenant. For more information please click here.

What are "registered offsite biodiversity gains allocated to the development"?

Where the biodiversity gain objective cannot be achieved through onsite habitat enhancements, any shortfall may be met through a "registered offsite biodiversity gain" which is allocated to the development. This is any habitat enhancement where:

  • the enhancement is required to be carried out under a conservation covenant or planning obligation (which will be the vehicle for allocating the gain to the development in question); and
  • it is recorded in the "biodiversity gain site register" which will be established by future regulations.

A "biodiversity gain site" is land where:

  • a person is required under a conservation covenant or planning obligation to carry out works for the purpose of habitat enhancement on that land;
  • that person, or another, is required to maintain the enhancement for at least 30 years after the completion of those works; and
  • the terms of the covenant or obligation make the enhancement available for allocation to one or more developments for which planning permission is granted. Ensuring that a biodiversity gain site can properly be allocated to a particular development may require forward planning.

In essence, a biodiversity gain site allows offsite enhancements to offset any onsite losses or to increase onsite gains. The government's intention is that a "biodiversity unit market" will develop, with landowners undertaking biodiversity enhancements on their land which can be "sold" to developers needing to achieve offsite enhancements to meet the biodiversity gain objective.

What are "biodiversity credits"?

These should not be confused with "biodiversity units".

Statutory biodiversity credits will be sold by the UK government to developers as a last resort should it not be possible for them to meet the biodiversity gain objective through habitat enhancements on site or the allocation of offsite registered biodiversity gains or the purchase of biodiversity units on the open market.

Developers will be able to purchase biodiversity credits at a set price, which is yet to be announced but is intended to achieve an appropriate balance between:

  • offering a cost-effective way to achieve net gain where this cannot be achieved otherwise;
  • driving growth in the biodiversity unit market; and
  • raising sufficient funds to cover administrative costs of the biodiversity credit scheme and to deliver the intended biodiversity outcomes, with at least one biodiversity unit being created for every credit sold. 

The UK government expects but cannot guarantee that a biodiversity market will meet demand for biodiversity units from day one. Therefore, the price of statutory biodiversity credits is to be intentionally uncompetitive as compared to the biodiversity unit market, and the government's intention is that biodiversity credits will only be made available in the early years following the mandatory biodiversity net gain provisions coming into effect.

Key contacts

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Martyn Jarvis

Senior Associate, London

Martyn Jarvis
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Fiona Sawyer

Professional Support Lawyer, London

Fiona Sawyer

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London Environment, Planning and Communities ESG Future Cities Martyn Jarvis Fiona Sawyer