Biodiversity Net Gain

Planning permissions for ‘in scope’ developments will be subject to a general pre-commencement biodiversity gain condition. The condition will require in-scope development to deliver at least a 10% increase in relation to the pre-development biodiversity value of the development which is granted planning permission, hereafter referred to as BNG.

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 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.

Achieving at least a 10% increase in BNG will become mandatory for applications for major development submitted on or after 12th February 2024 and for applications for minor development submitted on or after 2nd April 2024.

Applications for major development which have been submitted prior to the 12^th February and applications for minor development submitted prior to the 2^nd April 2024 will not be required by legislation to provide at least a 10% increase in BNG. However, planning policy does seek to achieve no net loss in biodiversity.

Major developments are subject to BNG as of 12^th February and are defined as:

(a) the winning and working of minerals or the use of land for mineral-working deposits;

(b) waste development;

(c) the provision of dwellinghouses where —

(i) the number of dwellinghouses to be provided is 10 or more; or

(ii) the development is to be carried out on a site having an area of 0.5 hectares or more and it is not known whether the development falls within sub-paragraph (c)(i);

(d) the provision of a building or buildings where the floor space to be created by the development is 1,000 square metres or more; or

(e) development carried out on a site having an area of 1 hectare or more;

Minor developments are subject to BNG as of 2^nd April 2024 and are defined as residential sites of no more than 9 dwellings or sites of less than 0.5ha where number of dwellings is unknown; and non-residential schemes where the floorspace is less than 1000 m or the site is less than 1ha in size.

The following types of development are exempt from the BNG requirement:

• Householder applications;
• Permitted development;
• Minor developments where an application has been made or granted prior to the 2nd April 2024;
• Applications subject to the de minimis exemption where the development does not impact a priority habitat (as listed within Section 41 of the Natural Environment and Rural Communities Act 2006) and impacts less than 25m2 of habitat that has a biodiversity value of greater than 0; and less than 5m of a linear habitat (e.g. hedgerow or watercourse);
• Biodiversity Gain sites – developments which fulfil the BNG requirement arising from another development;
• Self-build and custom build applications where the development:
  • Consists of no more than 9 dwellings
  • Is carried out on a site which has an area of no less than 0.5 Ha; and
  • Consists exclusively of dwellings which are self-build or custom housebuilding.

BNG also does not apply to retrospective planning permissions made under Section 73A, Section 73 permissions where the original permission which the Section 73 relates to was either granted before 12th February 2024 or the application for the original permission was made before 12^th February 2024.

BNG has not yet been commenced for local development orders, neighbourhood development orders, successful enforcement appeals, or deemed planning permissions. It will not apply to permissions in principle (though it will apply to the subsequent technical details consent) or applications for approval of reserved matters (as they are not a grant of planning permission).

The pre-development biodiversity value of the on-site habitat is taken at the date on which the planning application is submitted, or in any other case, the date on which planning permission is granted.

There are special provisions for the calculation of the pre-development biodiversity value of onsite habitat when loss or impact to habitats (or ‘degradation’) has occurred prior to the submission of a planning application in order to discourage the deliberate degradation of existing onsite habitats to reduce the pre-development biodiversity value.

Where unauthorised degradation of the onsite habitat has taken place on the land between 30 January 2020 and the date of the planning application/permission, the biodiversity pre-development value of the onsite habitat should be calculated as the biodiversity value of the habitat on the date immediately before the carrying out of these degradation activities. The relevant date should therefore be set as a date immediately before these activities.  Unauthorised degradation of onsite habitat is any degradation which is not in accordance with a previous planning permission.

If activities to implement or in connection with a planning permission are carried out after 25 August 2023 that lower the biodiversity value of the onsite habitat, the pre-development biodiversity value of the onsite habitat is taken to be the biodiversity value immediately before the carrying out of the activities. The relevant date should therefore be set as a date immediately before these activities.

If there has been degradation and there is insufficient evidence about the biodiversity value of the onsite habitat immediately before the degradation, the pre-development biodiversity value of the onsite habitat must be taken to be the highest biodiversity value of the habitat which is reasonably supported by any available evidence relating to it. This requirement must be applied to the calculation of pre-development biodiversity value in the metric tool, and the Biodiversity Gain Plan template asks for information regarding whether there has been prior habitat degradation.

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 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;
• area;
• distinctiveness;
• condition; and
• its location in respect to areas covered by natural environment policies.

Biodiversity units are divided into habitat units, hedgerow units and river units, all of which must be increased by at least 10%. For example, if habitat units are increased by more than 10%, the surplus in habitat units over 10% cannot be used to make up a shortfall in river units. These are referred to as the ‘trading rules’.

For clarity, the trading rules are:

1. The trading rules of this biodiversity metric must be followed.
2. Biodiversity unit outputs, for each type of unit, must not be summed, traded, or converted between types. The requirement to deliver at least a 10% net gain applies to each type of unit.
3. To accurately apply the biodiversity metric formula, you must use the statutory biodiversity metric calculation tool or small sites biodiversity metric tool (SSM) for small sites. The tools remove the need for a user to manually calculate the change in biodiversity value. The tool will summarise the results of the calculation and inform a user whether the biodiversity net gain objective has been met.
4. 4 In exceptional ecological circumstances, deviation from this biodiversity metric methodology may be permitted by the relevant planning authority.

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

The statutory biodiversity metric and information on how it is used can be found in the Statutory Biodiversity Metric User Guide.

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 (LPA) 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.

The biodiversity gain hierarchy means taking the following actions in the following order of priority:

• avoiding adverse effects of the development on any onsite habitat with a habitat distinctiveness score, applied in the statutory biodiversity metric, equal to or higher than six;
• so far as those adverse effects cannot be avoided, mitigating those effects;
• so far as those adverse effects cannot be mitigated, habitat enhancement of onsite habitat;
• so far as there cannot be that enhancement, creation of onsite habitat;
• so far as there cannot be that creation, the availability of registered offsite biodiversity gain;
• so far as that offsite habitat enhancement cannot be secured, purchasing biodiversity credits.

The enhancement and creation of habitats within a development site is the preferred option for the delivery of BNG as it ensures that ecological connectivity and value is kept within the vicinity of habitats that are being lost. This is also important to ensure that local communities benefit from the creation of biodiverse and nature rich environment.

In proposing to create or enhance habitats, the targets should be realistic and deliverable within the lifetime of the development and this needs to be a key consideration in the design of high-quality schemes within developments. Open space within development is subject to recreational pressures such as informal play, exercise, and dog walking which impose additional considerations in determining what type and condition habitats within development sites can realistically achieve. For example, a habitat which is regularly disturbed by recreation is unlikely to achieve the same condition as a habitat which is undisturbed.

If a developer intends to satisfy their BNG requirements on land outside of the red line boundary of the development site, they can undertake habitat creation or enhancement or purchase credits via the private market, or statutory credits. In the event of off-site delivery, the developer will need to enter into a Section 106 Agreement with the LPA and then register the offsite area with Natural England, following the same process as for Habitat Banks.

Biodiversity gains may be delivered anywhere in England, but you should consider the following when deciding where to source your off-site biodiversity gains.

• The biodiversity metric incentivises off-site gains close to the development site. This is so that communities local to the development benefit from increases in biodiversity. Except for intertidal, watercourse or linear habitat, off-site gains in a neighbouring LPA will be worth fewer biodiversity units than off-site gains in the same LPA as the development. Off-site gains beyond the neighbouring LPA will be worth even fewer.
• The metric also provides an incentive to achieve off-site biodiversity gains in areas of strategic significance. Strategically significant areas are set in your local nature recovery strategy. Where this is not yet available, your LPA may recommend you use a draft strategy, or an alternative strategy. You can find your LPA with a postcode for your site.

The off-site land will need to be secured for a minimum of 30 years and will need to be managed, monitored and reported on for the duration of the legal agreement.

We are unable to recommend third-party offset providers at this stage as a national or local list of such providers is not yet available. However, you may want to approach BNG brokers, Habitat Banks, local landowners, land managers or nature conservation trusts to help you achieve your biodiversity net gain requirements.

The following national validation requirements have been imposed and the following information must be submitted to support a planning application:

• a statement as to whether the applicant believes the development is subject to the biodiversity gain condition (on application form). If the Applicant believes that the development would not be subject to the condition, the application must be supported by a statement setting out what exemption(s) or transitional provision(s) apply;
• confirmation that the applicant believes that if planning permission is granted, the development would be subject to the biodiversity gain condition;
• the pre-development biodiversity value(s), either on the date of application or earlier proposed date (as appropriate);
• where the applicant proposes to use an earlier date, this proposed earlier date and the reasons for proposing that date;
• the completed metric calculation tool showing the calculations of the pre-development biodiversity value of the onsite habitat on the date of application (or proposed earlier date) including the publication date of the biodiversity metric used to calculate that value;
• a statement confirming whether activities have been carried out prior to  the date of application (or earlier proposed date), that result in loss of onsite biodiversity value (‘degradation’), and where they have:
  • a statement to the effect that these activities have been carried out;
  • the date immediately before these activities were carried out;
  • the pre-development biodiversity value of the onsite habitat on this date;
  • the completed metric calculation tool showing the calculations, and
  • any available supporting evidence of this;
• a description of any irreplaceable habitat (as set out in column 1 of the Schedule to the Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations 2024) on the land to which the application relates, that exists on the date of application, (or an earlier date); and
• plan(s), drawn to an identified scale and showing the direction of North, showing onsite habitat existing on the date of application (or earlier proposed date), including any irreplaceable habitat (if applicable).

If this information has not been provided, the local planning authority will likely refuse to validate the application. Within the planning application form applicants will be asked to confirm whether this information accompanies the application. Where these details have been provided elsewhere in accompanying documents, applicants are encouraged to cross-reference to these rather than duplicate this information within the application form.

Applicants should be aware that local planning authorities may request further information relating to biodiversity net gain as part of the planning application.

BNG is a material consideration when determining applications and guidance from the Government makes it clear that the LPA needs to understand how the BNG requirement is to be met prior to determining the application, so that necessary planning conditions can be imposed and/or S.106 Agreements signed.

A Biodiversity Net Gain Assessment must be provided outlining how the Biodiversity Gain Objective will be met. This must be prepared by a professional ecologist with suitable qualifications and experience and be in accordance with the British Standard BS8683 ‘Process for designing and implementing biodiversity net gain – specification’. Biodiversity net gain must always follow the principles outlined in ‘Biodiversity Net Gain – Good Practice Principles for Development’

The assessment should include details of:

• Information required through Paragraph reference ID 74-011-20240214 of the Biodiversity Net Gain Planning Practice Guidance;
• The proposed methods of delivery of the biodiversity gain objective including onsite gains, off-site gains and the use of statutory biodiversity credits;
• How the biodiversity gain hierarchy has been considered and adhered to;
• Information about any potential planning obligations required to deliver the biodiversity gain objective connected to the planning application (e.g. should a S106 agreement be required to secure significant areas of onsite habitat).

A draft version of the Statutory Biodiversity Metric Calculation Tool (in Excel format) must be submitted. This should be completed in accordance with the Biodiversity Metric Principles included in ‘The Statutory Biodiversity Metric User Guide’ published by DEFRA. As a minimum this should include completed sections for onsite pre-and post-development habitat delivery.

The following supporting information must be submitted alongside the metric:

• Completed statutory biodiversity metric condition assessments for baseline habitats, including supporting information i.e. species lists and quadrat locations;
• Predicted habitat condition assessments of created/enhanced post-development habitats and details of the realistic and appropriate interventions/management regimes which are being suggested to achieve the stated condition/s and secure the biodiversity enhancements for a minimum 30 years post enhancement/creation;
• Pre- and post- development site plans clearly showing polygons and areas for each habitat used to populate the statutory metric calculation tool using UK Habitat Classification symbology (shapefiles in GIS or AutoCAD may be requested). The plans must be drawn to an identified scale and show the direction of north. Plans using Phase 1 symbology are not acceptable.
• Polygons within pre- and post-development plans should be labelled with a Habitat Reference Number which should also be noted within the associated column within the Statutory Metric Tool.

Where it is suspected the baseline value of a site has been affected negatively prior to assessment the LPA may require an assessment of the site based on its condition before such an occurrence. This may need to be based on aerial photos and/or historic information held by the Council and if there is any doubt regarding the Distinctiveness or Condition of habitats/features it will be assumed that the highest likely value will apply.

The Town and Country Planning Act has been amended to make every grant of planning permission deemed to have been granted subject to the following general planning condition:

The development may not be begun unless –

• a biodiversity gain plan has been submitted to the planning authority; and
• the planning authority has approved the plan.

In the case of a Phased development, the following planning condition would be deemed to be imposed:

The development may not be begun unless— 

• A biodiversity net gain plan for the overall development has been submitted to the planning authority; and
• The planning authority has approved the plan.

No phase of development may be begun unless

• A biodiversity net gain plan for that phase of the development has been submitted to the planning authority; and
• The planning authority has approved the plan.

In the case of an application made under Section 73, the following planning condition would be deemed to be imposed:

Where permission has been granted on an application made under section 73(1) (determination of applications to develop land without compliance with conditions previously attached), no further development of a phase which has been begun may be carried out pursuant to that permission unless the requirement in sub-paragraph (5) or (6) has been met –

5) The requirement in this sub-paragraph has been met where—

(a) a biodiversity gain plan for that phase has been submitted to the planning authority (see modified paragraph 14), and

(b) the planning authority has approved that plan (see modified paragraph 15).

(6) The requirement in this sub-paragraph has been met where—

(a) permission has been granted on an application made under section 73, and

(b) an earlier biodiversity gain plan for that phase is regarded as approved under section 73(2C) and (2D) for the purpose of the permission granted under section 73.

Because the general biodiversity gain condition has a separate statutory basis to other planning conditions and is deemed to apply to all planning permissions other than specifically exempted ones, LPAs have been instructed not to include it in the list of conditions imposed in the decision notice. Instead, the decision notice will include information about BNG, for which the Government will provide model paragraphs.

The statutory basis for the deemed condition also means material considerations, for example viability, cannot be used to justify the omission of the condition.

The deemed condition cannot be varied or removed under Section 73 of the Town and Country Planning Act 1990.

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 (see 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 30C(2) and 30C(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;
• the reference number of the planning permission to which the plan relates;
• a description of the development to which the plan relates;
• the completed biodiversity metric calculation tool, stating the version of the biodiversity metric used and showing the calculation of the pre-development 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);
• (in cases where there is no irreplaceable habitat on the development site) how the biodiversity gain hierarchy will be followed and where to the extent any actions in that hierarchy are not followed and the reason for that;
• the relevant date for the purposes of calculating the pre-development biodiversity value of onsite habitats;
• pre-development and post-development plans —
  • showing the location of onsite habitat;
  • drawn to an identified scale and showing the direction of North; and
• in relation to 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.

The statutory framework for BNG includes specific modifications for planning permissions (including outline permissions) that have the effect of permitting development which proceed in phases. This reflects that phased development can occur over a long period of time where full details of all phases may not be known at the time of planning permission. For these permissions, the standard approach may not be possible. The arrangements for approving the biodiversity gain plan for phased development need to follow a different approach.

These apply to:

• a grant of outline planning permission where the reservation of matters for subsequent approval has the effect of requiring or permitting development to proceed in phases;  or
• a grant of any kind of planning permission, where the grant is subject to conditions which requires development to proceed in phases.

When granting planning permission for a development which is to be phased, the decision-maker will indicate on the written decision notice whether the development is to proceed in phases. The decision notice will also include information relating to the approval of the biodiversity gain condition and that the phase development modification would apply. Applicants may want to confirm with the planning authority that the development is phased prior to submitting an Overall Biodiversity Gain Plan.

Instead of the standard approach for the Biodiversity Gain Plan, the following will be required:

• an Overall Biodiversity Gain Plan must be submitted to and approved by the planning authority before any development can be begun. It must include:
  • the post-development biodiversity value of the onsite habitat for the phase of the development (which is the subject of the Plan);
  • the post-development biodiversity value of the onsite habitat for each other phase of development (whether begun or otherwise);
  • any registered offsite biodiversity gain allocated to the entire development and the biodiversity value of that gain for the development prior to submission of the phase plan;
  • any registered offsite biodiversity gain which is proposed to be allocated to the entire development and the biodiversity value of that gain in relation to the development;
  • any biodiversity credits purchased for the entire development prior to submission of the phase plan; and
  • any biodiversity credits proposed to be purchased for the entire development.
• a Phase Biodiversity Gain Plan for each phase must be submitted to and approved by the planning authority before the development of that phase can be begun. It must include:
  • name and address of the person completing, and (if different) the person submitting the plan;
  • description of the development and planning permission reference number (which the person submitting the plan considers is relevant to the phase of development);
  • post-development plans for the phase of development showing the location of existing onsite habitat (including any irreplaceable habitats) and drawn to an identified scale and showing the direction of North;
  • a completed biodiversity metric calculation tool(s) stating the publication date of the biodiversity metric used and showing the calculation of the pre-development and post-development biodiversity values;
  • information about the steps taken or to be taken to minimise the adverse effect of the phase of development on the biodiversity of the onsite habitat;
  • arrangements for the maintenance and monitoring of significant onsite habitat enhancements;
  • a description of how the Biodiversity Gain Hierarchy will be followed and where to the extent any actions in that hierarchy are not followed, the reasons if not (except for irreplaceable habitats); and
  • 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.

In recognition that phased development can often be implemented over a long period of time, the purpose of the Overall Biodiversity Gain Plan is to set a clear upfront framework for how the biodiversity gain objective of at least a 10% gain is expected to be met across the entire development.

Each Phase Biodiversity Gain Plan will subsequently set out a phase’s contribution to biodiversity net gain and track progress towards the overall biodiversity gain objective for the development once clear proposals for each phase have been developed. It is envisaged that, for an outline planning permission for phased development, the Phase Biodiversity Gain Plan would be prepared alongside the application for reserved matter approvals for a phase.