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Biodiversity Net Gain

The biodiversity net gain requirement

The Government first announced its intention to introduce biodiversity net gain requirements in 2019.

All planning applications which are not exempt and are submitted on or after 2 April 2024 are subject to the statutory requirements of Biodiversity Net Gain (BNG).

The law requires that all non-exempt applications must deliver a minimum 10% increase in Biodiversity Net Gain.

The Biodiversity Supplementary Planning Document, adopted in December 2024, provides advice and guidance about how biodiversity can be protected and enhanced. The SPD guides developers, planners, and consultants about how biodiversity net gain will be integrated into the development process to ensure that legislation, policy, and best practice standards are met.

Exemptions

The legal biodiversity net gain requirement does not apply to:

  1. Householder development
  2. Section 73 applications to vary a condition – but only where the original permission was not subject to BNG provisions.
  3. Development granted permission by a development order (e.g. permitted developments, such as notification of intent applications for agricultural/forestry buildings).
  4. Development where the application site has no current biodiversity value – for example applications where the entire site is covered in hard surfaces either buildings or sealed hardstanding.
  5. Development which does not impact a priority habitat and impacts less than 25 square metres of habitat or 5 metres of linear habitats.
  6. Self-build and custom build developments which:
    1. consists of no more than 9 dwellings, and
    2. is carried out on a site which has an area no larger than 0.5 hectares, and
    3. consists exclusively of dwellings which are self-build or custom housebuilding as defined in section 1(A1) of the Self-build and Custom Housebuilding Act 2015.
  7. Development of a biodiversity gain site (development which is undertaken solely or mainly for the purpose of fulfilling, in whole or in part, the biodiversity gain planning condition which applies in relation to another development).

Validation requirements

Information required to validate applications which are not exempt from biodiversity net gain requirements
  1. A statement confirming the pre-development biodiversity value of the onsite habitat on the date of application (or an earlier date), including:
    1. The completed metric calculation tool showing the calculations
    2. The publication date and version of the biodiversity metric used to calculate that value
    3. The ecological competence and qualifications of the person completing the metric
  2. A statement confirming how the proposed development is intended to achieve a minimum of 10% biodiversity net gain including an indication of whether BNG will be delivered through:
    1. on-site provision, or
    2. off-site provision, or
    3. purchase of off-site biodiversity units, or
    4. purchase of statutory credits, or
    5. a combination of two or more of the above.
  3. A statement confirming how the proposals comply with the Biodiversity Net Gain Hierarchy and trading rules.
  4. A statement confirming whether the biodiversity value of the on-site habitat is lower on the date of application (or an earlier date) because of the carrying on of activities (‘degradation’) - in such instances the biodiversity value is taken as immediately before the carrying on of the activities, and if degradation has taken place supporting evidence of this.
  5. If it is proposed to use a pre-development biodiversity value of the on-site habitat for a date earlier than the date of application, a statement confirming the proposed earlier date and the reasons for proposing that date.
  6. If the land contains any irreplaceable habitat (as set out in column 1 of the Schedule to the Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations 2024), a statement providing:
    1. A description of the irreplaceable habitat that exists on the land on the date of application, (or an earlier date); and
    2. A plan, drawn to an identified scale which must show the direction of North, showing onsite habitat existing on the date of application (or and earlier date), including any irreplaceable habitat.

If this information is not provided your application will not be valid.

Validation requirements

Information required to validate applications which an applicant considers are exempt from biodiversity net gain requirements
  1. A statement detailing why, if planning permission was granted, legal biodiversity net gain requirements would not apply; or
  2. An application form detailing why, if planning permission was granted, legal biodiversity net gain requirements would not apply

If this information is not provided your application will not be valid.

This requirement does not apply to Householder applications.

Validation requirements

Information required to validate retrospective applications where, if the application had been made in advance of development occurring, the development would have been subject to biodiversity net gain requirements
  1. A statement detailing why, if the application had not been retrospective, legal biodiversity net gain requirements would not have applied; or all of the information below.
  2. A statement confirming the pre-development biodiversity value of the onsite habitat on the date development began (or an earlier date), including:
    1. The completed metric calculation tool showing the calculations
    2. The publication date and version of the biodiversity metric used to calculate that value
    3. The ecological competence and qualifications of the person completing the metric
  3. A statement confirming the post-development biodiversity value of the onsite habitat, including:
    1. The completed metric calculation tool showing the calculations
    2. The publication date and version of the biodiversity metric used to calculate that value
  4. A statement how the development has achieved a minimum of 10% biodiversity net gain through:
    1. on-site provision, or
    2. off-site provision, or
    3. purchase of off-site biodiversity units, or
    4. purchase of statutory credits, or
    5. a combination of two or more of the above.
  5. Where the development has not already achieved a minimum of 10% biodiversity net gain, a compensation strategy showing how a minimum of 10% biodiversity net gain will be achieved (including the timetable for delivery and the mechanism by which compensation will be secured) through:
    1. on-site provision, or
    2. off-site provision, or
    3. purchase of off-site biodiversity units, or
    4. purchase of statutory credits, or
    5. a combination of two or more of the above.
  6. A statement confirming how the development complied or will comply with the Biodiversity Net Gain Hierarchy and trading rules.
  7. If it is proposed to use a pre-development biodiversity value of the on-site habitat for a date earlier than the date development occurred, a statement confirming the proposed earlier date and the reasons for proposing that date.
  8. If the land contains or contained any irreplaceable habitat (as set out in column 1 of the Schedule to the Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations 2024), a statement providing:
    1. A description of the irreplaceable habitat that exists on the land on the date of application, (or an earlier date); and
    2. A plan, drawn to an identified scale which must show the direction of North, showing onsite habitat existing on the date of application (or and earlier date), including any irreplaceable habitat.

If this information is not provided your application will not be valid.

What happens if planning permission is granted?

The law, through Schedule 7A of the Town and Country Planning Act 1990 (as inserted by Schedule 14 of the Environment Act 2021) makes it a condition of any relevant planning permission that:

"the development may not be begun unless:

(a) a biodiversity gain plan has been submitted to the planning authority, and

(b) the planning authority has approved the plan."

You will need to submit your final biodiversity gain plan for approval, and receive that approval, before you commence works. If works proceed in breach of this condition your whole development may be unauthorised. You will then be at risk of formal enforcement action and/or need to make a further full planning application.

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