What is Biodiversity Net Gain?

The natural environment is deteriorating, in order to address this decline the government has introduced  mandatory biodiversity net gain requirements through the planning system.

Biodiversity Net Gain (BNG) is an approach to development that aims to leave the natural environment in a measurably better state than it was beforehand. It is calculated using the statutory biodiversity metric.

The biodiversity gain condition (see below) requires developers of ”in scope” development  to deliver at least a 10% increase in relation to the pre-development biodiversity value of the development granted planning permission.

BNG can be delivered on site, off site (through registered offsite biodiversity gains) or through the purchase of statutory bio diversity credits. However, in accordance with the biodiversity gain hierarchy (see below) there is a clear preference for onsite delivery.  Any habitat enhancement delivered must be maintained for at least 30 years after the development is completed.

The government guidance encourages applicant’s to consider BNG early in the development process, and factor it into site selection and design, and to discuss the BNG requirements for their proposal with the local planning authority through its pre-application advice service (see below).

The Biodiversity Gain hierarchy

Developers are encouraged to follow the Biodiversity Gain Hierarchy from the earliest stage possible when selecting a site and considering development proposals. Local planning authorities must take into account the Biodiversity Gain Hierarchy when considering whether the biodiversity objective has been met and when determining whether to approve the Biodiversity Gain Plan (see below).

The Biodiversity Gain Hierarchy (which does not apply to irreplaceable habitats) sets out a list of priority actions:

  • first, in relation to onsite habitats which have a medium, high and very high distinctiveness (a score of four or more according to the statutory biodiversity metric), the avoidance of adverse effects from the development and, if they cannot be avoided, the mitigation of those effects; and
  • then, in relation to all onsite habitats which are adversely affected by the development, the adverse effect should be compensated by prioritising in order, where possible, (i) the enhancement of existing onsite habitats, (ii) creation of new onsite habitats, (iii) allocation of registered offsite gains and finally (iv) the purchase of biodiversity credits.

The Biodiversity Gain Hierarchy is set out in full within section 37A of the legislation and can be viewed here; https://www.legislation.gov.uk/uksi/2015/595/article/37A.

The Biodiversity Gain condition

From 12th February 2024 planning permissions for ‘in scope’ developments relating to applications made after that date are subject to a general pre-commencement biodiversity gain condition. The condition will require in scope development to deliver at least a10% increase in relation to the pre-development biodiversity value of the development granted planning permission. The general biodiversity condition will not appear on the decision notice as it is a national requirement, other than it will be referenced in an informative note.  It will be a pre-commencement condition which will need to be discharged along with any other pre-commencement conditions prior to the commencement of development through the submission and approval of a Biodiversity Gain Plan. Thereafter the Biodiversity Gain Plan will need to be implemented and maintained as approved.    

In England, the relevant primary legislation for the statutory framework for biodiversity net gain is principally set out under Section 90A and Schedule 7A (Biodiversity Gain in England) of the Town and Country Planning Act 1990. This legislation was inserted into the Act by Schedule 14 of the Environment Act 2021 and includes amendments made by the Levelling Up and Regeneration Act 2023 and the Biodiversity Gain (Town and Country Planning) (Consequential Amendments) Regulations [2024].

The relevant BNG regulations most directly relevant to planning are:

  • The Environment Act 2021 (Commencement No. 8 and Transitional Provisions) Regulations [2024] 
  •  The Biodiversity Gain Requirements (Exemptions) Regulations [2024] 
  •  The Biodiversity Gain (Town and Country Planning) (Modifications and Amendments) (England) Regulations  [2024] 
  •  The Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations [2024] 

In addition, there are regulations for the Biodiversity Gain Site register established under section 100 of the Environment Act 2021 for registered offsite biodiversity gains.

What development is ‘in scope’?

While every grant of planning permission in England is deemed to have been granted subject to the general biodiversity gain condition, commencement and transitional arrangements, as well as exemptions, mean that certain permissions are not subject to biodiversity net gain. 

BNG has only been commenced for planning permissions granted in respect to an application made on or after 12 February 2024. Permissions granted for applications made before this date are not subject to biodiversity net gain.    

BNG does not apply to:

  • retrospective planning permissions made under section 73A; and
  • section 73 permissions where the original permission which the section 73 relates to was either granted before 12 February 2024 or the application for the original permission was made before 12 February 2024.

BNG has not been commenced yet for planning permissions which have been granted through other routes to permissions. These include:

  • Local development orders;
  • Simplified Planning Zones;
  • Neighbourhood development orders;
  • Successful enforcement appeals; and
  • Deemed planning permission.

The grant of permission in principle is not within the scope of BNG (as it is not a grant of planning permission), but the subsequent technical details consent (as a grant of planning permission) would be subject to the biodiversity gain condition.   

The approval of reserved matters for outline planning permissions is not subject to the BNG (as it is not a grant of planning permission).

There are specific exemptions from biodiversity net gain for certain types of development. The exemptions are set out in paragraph 17 of Schedule 7A of the Town and Country Planning Act 1990 and the Biodiversity Gain Requirements (Exemptions) Regulations 2024.

The BNG does not apply to the following types of development: 

  • Temporary exemption for non-major development (until April 2024). Development which is not defined as major development under Article 2 Town and Country Planning (Development Management Procedure) (England) Order 2015 is exempt until 2 April 2024. The exemption will continue to apply to section 73 permissions where the original permission which the section 73 relates to was subject to this temporary exemption.
  • Householder development. Development which is subject of a householder application as defined within Article 2(1) of the Town and Country Planning (Development Management Procedure) (England) Order 2015.
  • Development granted planning permission by a development order under section 59. This includes permitted development rights.
  • Development subject to the de minimis exemption. Development that does not impact a priority habitat and impacts less than 25 square metres (e.g. 5m by 5m) of onsite habitat, and 5 metres of linear habitats such as hedgerows.
  • Self-build and custom build development. Development which
  • Urgent Crown development granted permission under section 293A of the Town and Country Planning Act 1990.
  • 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 condition which applies in relation to another development.
  • Development related to the high speed railway transport network. Development forming part of, or ancillary to, the high speed railway transport network comprising connections between all or any of the places or parts of the transport network specified in section 1(2) of the High Speed Rail (Preparation) Act 2013.

How is the Biodiversity Gain objective of 10% gain calculated? 

The biodiversity gain objective of at least a 10% gain is measured against the pre-development biodiversity value of the onsite habitat for the development. The objective is met if the post-development biodiversity value is exceeded by at least 10%. This 10% gain is calculated in reference to:

  • the projected biodiversity value of the onsite habitat at the time the development is completed (“the post development biodiversity value of the onsite habitat”);
  • the biodiversity value in relation to the development of any registered offsite biodiversity gain allocated to the development; and
  • the biodiversity value of any biodiversity credits purchased for the development.

The statutory biodiversity metric is used to calculate the pre-development and post-development biodiversity value of the development’s onsite habitat, as well as the biodiversity value for offsite biodiversity gains and biodiversity credits. It uses habitat information to generate “biodiversity units”, a proxy measure for biodiversity value. The statutory biodiversity metric data value inputs include habitat type, size, distinctiveness, condition, and its location in the local area.

The statutory biodiversity metric calculation tools must be submitted as part of the Biodiversity Gain Plan to demonstrate the statutory biodiversity metric formula has been accurately applied.

The Department for Environment, Food and Rural Affairs have published guidance on the statutory biodiversity metric and information on how it is used.

Submitting an application (validation)

The BNG regulations impose additional national and local validation requirements these are reflected in  updates to our validation requirements and can be viewed here: https://www.hartlepool.gov.uk/info/20222/planning/381/planning_application_validation.


The Biodiversity Gain Plan – Post Permission Requirements for In Scope Development

The regulations apply a pre-commencement condition to all in scope development this will require a Biodiversity Gain Plan to be submitted and approved by the Local Planning Authority prior to the commencement of development.  It is treated as a discharge of condition application and attracts the same fee.  A discharge of conditions application form should be used. It is anticipated that robust proposals will have been discussed and agreed at the application stage to assist in the timely discharge of this condition.    

The following content of a Biodiversity Gain Plan is required for standard development which is not to proceed in phases. Where planning permission is granted that has the effect of permitting development in phases, there are different requirements for the Biodiversity Gain Plan (please see Planning Practice Guidance link below).

Under paragraph 14(2) of Schedule 7A a Biodiversity Gain Plan must include the following matters:

  • information about the steps taken or to be taken to minimise the adverse effect of the development on the biodiversity of the on-site habitat and any other habitat
  • the pre-development biodiversity value of the on-site habitat
  • the post-development biodiversity value of the on-site habitat
  • any registered off-site 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

In addition, under Articles 37C(2) and 37C(4) of The Town and Country Planning (Development Management Procedure) (England) Order 2015 the following specified matters are required, where development is not to proceed in phases:

  • name and address of the person completing the Plan, and (if different) the person submitting the Plan;
  • a description of the development and planning permission reference number (to which the plan relates);
  • the relevant date, for the purposes of calculating the pre-development biodiversity value of onsite habitats and if proposing an earlier date, the reasons for using this earlier date;
  • the completed biodiversity metric calculation tool(s), stating the publication date of the tool(s), and showing the calculation of the pre-development onsite value on the relevant date, and post-development biodiversity value;
  • a description of arrangements for maintenance and monitoring of habitat enhancement to which paragraph 9(3) of Schedule 7A to the 1990 Act applies (habitat enhancement which must be maintained for at least 30 years after the development is completed);
  • (except for onsite irreplaceable habitats) a description of how the biodiversity gain hierarchy will be followed and where to the extent any actions (in order of priority) in that hierarchy are not followed and the reason for that;
  • pre-development and post-development plans showing the location of onsite habitat (including any irreplaceable habitat) on the relevant date, and drawn to an identified scale and showing the direction of North;
  • a description of any irreplaceable habitat on the land to which the plan relates which exist on the relevant date, and any part of the development for which planning permission is granted where the onsite habitat of that part is irreplaceable habitat arrangements for compensation for any impact the development has on the biodiversity of the irreplaceable habitat; and
  • if habitat degradation has taken place:
    • a statement to this effect,
    • the date immediately before the degradation activity,
    • the completed biodiversity tool showing the calculation of the biodiversity value of the onsite habitat on that date, and
    • any available supporting evidence for the value.

There is a standard Biodiversity Gain Plan template link below available to complete which brings together many of these matters into one document:

Biodiversity Gain Plan - GOV.UK (www.gov.uk)

A Biodiversity Gain Plan must be submitted no earlier than the day after the relevant planning permission has been granted.  Once approved it cannot be amended however  a new Biodiversity Gain Plan can be submitted to the planning authority for approval before the commencement of development. When submitting this it should be made clear that the intention is that the new plan will supersede any previously approved plan.

How can I obtain further advice?

See the Detailed Planning Practice Guidance on BNG:

https://www.gov.uk/guidance/draft-biodiversity-net-gain-planning-practice-guidance

The government guidance emphasis the importance of pre-application discussions.  The council operates a fee-based One Stop Shop service which can be utilised for pre-application advice in relation to proposed developments. If you wish to obtain specific advice on BNG you should state this.  The advice will be most useful if you have considered your proposals in advance including completing the relevant pre and post development biodiversity metric tools where possible. There may be an additional charge for this service. Details of the One Stop Shop Service can be found in the link below:

One Stop Shop | Planning Advisory Service | Hartlepool Borough Council

Disclaimer

This page provides a brief overview of the topic at the time of publication.  It does not provide comprehensive advice and guidance on all aspects of BNG.  In all cases reference should be made to the most up to date guidance. 

Last Updated 25/06/82025