The Biodiversity Net Gain process: developer and LPA perspectives

You may already know that delivering biodiversity net gain (BNG) is now a statutory requirement; developments in England (with very limited exceptions) must demonstrate that they will provide at least a 10% increase in the biodiversity value of habitats, preferably on the development site (the BNG requirement). 

So if you're a developer, local planning authority (LPA) or land manager, you'll need to get to grips with the BNG requirement.

A hierarchy applies to the delivery of BNG which means that, the preferred route is that the requirement is fully delivered on-site (route one). If that is not possible BNG can be delivered off-site by allocating off-site gains to the development (either through the developer carrying out off-site habitat enhancement works themselves or by purchasing 'BNG units' (route 2). As a last resort it will be permissible for a developer to purchase 'biodiversity credits' from the government (route 3). It is possible for the BNG requirement to be met through a combination of routes 1, 2 and 3.

Habitat that is created or enhanced to deliver the BNG requirement, must be secured for a minimum of 30 years.

Only the approved biodiversity metric calculation (main or small sites version) can be submitted to evidence the BNG requirement is met.

This timeline sets out the process from start to finish – from pre-application to decision.

Looking for the Government guidance?

• If you're a developer, click here
• If you're an LPA, click here
• If you're a land manager, click here. 

The developer's perspective

Pre-application

Is your site exempt from the BNG requirement?

The starting point is that in England from:

• 12 February 2024 for major development
• 2 April 2024 for small developments

every grant of planning permission is deemed to have been granted subject to a condition requiring a biodiversity gain plan, securing the BNG requirement, to be approved before development is commenced (the BNG condition). An alternative version of the BNG condition applies to phased developments.

The list of exemptions from this requirement is narrow, focused and only open to certain types of application.

The applicant will need to provide detailed reasons to justify any claim of exemption and may be required to provide evidence as well.

For more information on the exemptions, click here.

Stage one: site selection

• Use digital tools to help calculate the current biodiversity value as per the statutory biodiversity metric / Small Site Metric (SSM)
• Consider if there are any 'irreplaceable' or 'high distinctiveness' habitats on the site
• Consider any potential adverse effects that the development might have on all habitats within the site
• Consider the potential to compensate any adverse effects with on-site enhancements
• Understand whether any works may have been carried out after 30 January 2020 that have reduced the sites biodiversity value. Such works may be disregarded unless they were authorised by a planning permission, resulting in a higher pre-development biodiversity value and more challenging biodiversity requirement to meet.

Stage two: site feasability assessment

• Consider ability to comply with the 'BNG hierarchy', and compliance with the BNG requirement
• Consider eligibility to use the Small Site Metric (SSM) which will not require a suitably qualified ecologist
• Consider engaging a suitably qualified ecologist. The LPA cannot require the developer to use a particular ecologist
• Engage with the LPA's pre-application advice services, also to check if there are any LPA specific requirements
• Consider ability to purchase off-site biodiversity units, if the site cannot provide the BNG requirement via on-site habitat enhancement or creation
• Ensure that any off-site biodiversity units are registered on Natural England's Biodiversity Gain Sites Register and secured for at least 30 years by a legal agreement (Conservation Covenant or planning obligation (section 106 agreement)).

Note that the NPPF paragraph 186(c) provides strong policy protections for irreplaceable habitats stating that development resulting in the loss or deterioration of irreplaceable habitats should be refused unless there are wholly exceptional reasons, and a suitable compensation strategy exists.

Stage three: site design

The statutory biodiversity metric is used to calculate the pre-development and post-development biodiversity value of the development’s on-site habitat, as well as the biodiversity value for off-site biodiversity units and biodiversity credits.

How is biodiversity net gain applied through the planning process?

Applicants for development should:

• Ensure that proposed works fully comply with the BNG requirement
• Ensure that the final metric sheet that is submitted to the LPA is either, a statutory biodiversity metric sheet, or a Small Site Metric Sheet (SSM)
• Ensure a competent person (competent person: for the statutory metric, this must be a suitably qualified ecologist. For the SSM, it does not need to be an ecologist) conducts the site survey/s, needed to complete the relevant metric sheet
• Produce a statutory biodiversity metric sheet (or, if they are eligible, a SSM sheet) setting out the baseline habitat/s. DEFRA has published guidance on the statutory biodiversity metric and information on how it is used. 
• Use the statutory metric sheet to calculate the pre-development biodiversity value of the on-site habitat on the date of application (or earlier). The applicant will need to justify using an earlier date
• Produce a statement setting out whether activities have been carried out prior to the date of application (or earlier proposed date), that result in loss of on-site biodiversity value ('degradation'). If 'yes', the applicant is likely to need to provide additional information
• If applicable, a description of any irreplaceable habitat
• Produce plan/s, drawn to an identified scale and showing the direction of North, showing on-site habitat existing on the date of application (or earlier proposed date), and if applicable, including any irreplaceable habitat.

In addition the applicant should consider the following:

• Consider possible post-development assessment
• Consider if the LPA may have any relevant requirements in addition to the mandatory BNG requirements
• Engage with the LPA and make use of any pre-application advice services that are offered by them to see if there are specific LPA requirements
• Production of the first version of a post-development metric sheet
• Production of the draft Biodiversity Gain Plan (BNG Plan)
• Consider producing a draft Habitat Management and Monitoring Plan (HMMP) if there will be significant on-site habitat gains.

Planning application 

Stage four: Pre-application advice

This could help establish whether development proposals will be subject to BNG and, if they are, enable the LPA to provide feedback on the proposed strategy for achieving the BNG requirement.

This may also help to establish if the proposed development will be phased, and if the phase development modification for BNG will apply.

If available, the following may be useful to inform pre-application conversations with the LPA: 

• Applicant self-assessment information on whether BNG applies
• Draft BNG Plan or Ecological statement
• Preliminary biodiversity metric calculations
• Early thoughts on the BNG hierarchy
• Proposals for minimising biodiversity impacts, and how biodiversity might be enhanced
• Intentions about the role of on/off-site mitigation
• Draft legal agreement / planning obligation to secure BNG or heads of terms.

Stage five: validation of the planning application

If the following information has not been provided, the LPA is likely to refuse to validate the application:

• Statement as to whether the applicant believes that planning permission, if granted, would be subject to the BNG requirement
• The pre-development biodiversity value/s of the on-site habitat/s on the date of application (or an earlier date), including the completed metric calculation tool used showing the calculations, the publication date and version of the biodiversity metric used to calculate that value
• Where the applicant wishes to use an earlier date, the proposed earlier date and the reasons for proposing that date
• 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 which case the value is to be taken as immediately before the carrying on of the activities, completed metric calculation tool, and if degradation has taken place supporting evidence of this
• 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 with reasons), and
• Plan/s, drawn to an identified scale which must show the direction of North, showing on-site habitat existing on the date of application (or earlier proposed date), including, if applicable, any irreplaceable habitat.

An LPA may also seek further information about the proposed approach to meeting the BNG requirement for the development.

Stage six: consultation on the planning application

There are no statutory requirements to consult a particular body or organisation prior to determining a planning application specifically related to biodiversity net gain. The normal consultation arrangements for planning applications apply.

Decision and post-decision 

Stage seven: consideration and decision

The statutory framework for BNG requires the approval of a BNG Plan for the development before it can legally commence.

However, a full and complete BNG Plan is not required at this, decision making stage.

The LPA will want to consider, if the BNG requirement is capable of being delivered and the BNG condition is capable of being discharged successfully through the imposition of conditions and agreement of section 106 planning obligation to secure on-site biodiversity gains or/and registered off-site biodiversity units.

How does biodiversity net gain get taken into account in decision making?

Prior to the determination of the planning application, decision makers will also want to discuss with the applicant whether any section 106 planning obligations are required to secure either significant on-site habitat enhancements or off-site gains for the development.

Stage eight: decision notice and pre-commencement conditions

The BNG condition has a separate statutory basis to other planning conditions so it should not be listed alongside all other planning conditions. The government has said it will provide model wording to be used in decision notices.

However, the decision notice will state whether the development is phased for the purposes of delivering the BNG requirement.

For phased development, an overall BNG Plan must be submitted to and approved by the LPA before any development can lawfully begin, and a Phase BNG Plan (for each phase) must be submitted to and approved by the LPA before the development of that phase can lawfully begin. 

Stage nine: the BNG plan

The government have published a model BNG Plan template which should be used by developers and its use is strongly encouraged to bring together the required information into one document for approval.

There is no separate application form for the submission of the BNG Plan. As with the discharge of other conditions, LPAs will have eight weeks to approve the BNG Plan (unless another timescale is agreed).

If the BNG Plan is refused by the LPA, there is a right of appeal to the Secretary of State, under section 78 of the Town and Country Planning Act 1990.

Before making any appeal, it is encouraged to first consider re-engaging with the LPA to discuss whether any changes to the BNG Plan would make it more acceptable.

There are two guidance notes published by the government:

• Focused on timescales for making an appeal, and
• How to make and submit an online appeal.

Stage 10: legal agreement/planning obligation

If the off-site gain is secured with a legal agreement by the landowner, the developer does not need to enter a legal agreement.

If the developer is making:

• Off-site gains on their own land that’s outside the development site, they must secure these gains with a legal agreement
• Significant on-site enhancements, they need to enter a legal agreement as the landowner. The LPA might also need to be involved.

Phased developments will involve additional considerations for developers and LPAs to take into account through both legal agreements and contracts.

National PPG states that appropriately worded planning conditions and planning obligations would also help achieve effective monitoring and enforcement of BNG, particularly in relation to the maintenance and monitoring of significant on-site habitat enhancements and registered off-site biodiversity gains.

Developers will only need to be concerned by the monitoring requirements for on-site gains or off-site gains on their land (i.e. where they are a party to the legal agreement).

A suite of sample agreement templates to facilitate securing biodiversity gains can be found on the Planning Advisory Service website here.

Breach of planning control and enforcement 

Failure to comply with planning conditions is a breach of planning control. As such failure to comply with the BNG condition, e.g. by commencing development without approval of the BNG Plan, will be a breach of planning control.

LPAs have a range of planning enforcement powers and have responsibility for taking whatever enforcement action may be necessary, in the public interest, in their area.

Note that where the developer has purchased biodiversity units, they won't be responsible for a landowner's breach of their legal agreement. 

The Local Planning Authority's (LPA) perspective

The pre-application stage

Stage one: pre-application

It is important that BNG is considered throughout the planning process.

Prior to the submission of a relevant planning application, applicants should discuss LPAs using the pre-application advice process. This benefits the LPA and developer and enables them to establish at an early stage, whether BNG is required. If it is required, a strategy for delivery can be agreed. Applicants may want to submit a draft overall BNG plan as part of their planning application although further information about, for example, proposals for significant on-site enhancements and the approach to off-site gains may be required for significant on-site enhancements may be required so that these gains can be secured through planning conditions or S106 obligations, should planning permission be granted.

NB: BNG credits for LPAs

LPAs need to be satisfied by the evidence that not enough on-site or off-site gains can be made to meet the 10% BNG requirement, before they allow developers to buy statutory credits.

When it is agreed that a developer can buy statutory credits, LPAs should send an email confirmation of this without delay, so that the final BNG Plan can be submitted. They should advise developers not to buy statutory credits until they are able to discharge their non-BNG-pre-commencement planning conditions.

LPAs may need to advise developers on bespoke BNG compensation if they are building on some types of habitats.

The planning application stage

Stage two: consideration of the planning application

As specified, there are minimum national information requirements that the LPA must consider. It may also be appropriate for LPAs to ask for further information to assist in consideration of BNG as part of the determination of the planning application, where they believe this would be material to the consideration of the application.

LPAs should take a proportionate approach to these information requirements (which should be set out in the local lists), focussed on only necessary additional information and integrated with wider information on biodiversity and other environmental matters. Smaller developments should be subject to fewer information requirements than a major development.

An LPA should check:

• Confirmation that the applicant believes that planning permission, if granted would be subject to the BNG condition, accompanied by the minimum information set out in Article 7 of the TCPA (Development Management Procedure) Order 2015
• The pre-development biodiversity value(s), either on the date of application or earlier proposed date
• 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 on-site habitat on the date of application
• A statement where activities have been carried out prior to the date of application, that result in loss of on-site biodiversity value
• A description of any irreplaceable habitat, which exists on the date of the application, and
• Plans, drawn to scale and showing the direction of North showing on-site habitat existing on the date of the application.

If this information has not been provided, the LPA will likely refuse to validate the application.

If planning obligations are likely to be used to secure BNG, this is something that LPAs may want to add to local lists of information requirements if they are able to justify their inclusion in relation to any particular development.

Decision and post-decision

Stage three: Reviewing the BNG plan

What to check?

LPAs should check that the BNG Plan explains:

• How the developer has applied the biodiversity gain hierarchy
• The biodiversity unit values before and after development
• How the developer will deliver the 10% BNG.

The LPA must assess and decide whether to approve the final biodiversity metric calculation. It is up to the LPA to decide what expertise is needed to help assess the biodiversity metric submitted with the BNG Plan. They may decide to use an ecologist or one of their planning officers.

LPAs need to check that:

• The pre-development, post-development and total net change calculations match
• It meets the BNG trading rules
• The developer's habitat valuations are accurate.

If a small development uses off-site gains in their main bio-diversity metric, LPAs need to manually check the trading rules in the BNG Plan.

Asking developers to use the biodiversity gain plan template is not mandatory, but it could help with standardising the submission of BNG Plan and metric information.

Checking the biodiversity gain sites register for off-site gains:

LPAs should check that the amount and type of any off-site gains listed in the developer's BNG Plan match the allocation recorded on the biodiversity gain sites register, operated by Natural England.

Before the LPA approves a BNG Plan, it must check that:

• Any off-site gains in the plan have been registered
• Those off-site gains have been recorded as allocated to the development in question
• The biodiversity value of the gains in the gain plan matches the value recorded on the register.

How to check the right statutory credits have been purchases:

The developer will provide proof of purchase of statutory biodiversity credits, which will state the number of credits of each tier they have bought. They will also provide their final metric calculation. LPAs will need to check that the developer has bought the correct number of statutory credits from each price tier, using the unit shortfall summary from their metric calculation.

Stage four: approving a BNG plan

The LPA must only approve a BNG Plan if they are satisfied that:

• The pre-development biodiversity value of the on-site habitat is as specified in the plan
• The post-development biodiversity of the on-site habitat is at least the value specified in the plan
• In the case where the registered off-site biodiversity gain is specified in the plan, as allocated to the development:

1. The registered off-site biodiversity gain is so allocated
2. The registered off-site biodiversity gain has the biodiversity value specified in the plan in relation to the development

• That any biodiversity credits specified in the plan as purchased for the development have been so purchased
• The BNG objective is met.

The LPA must also take into account how the Biodiversity Gain Hierarchy will be followed, and any reasons for the determination, specifying all elements of the biodiversity gain plan which are relevant to the determination.

LPAs must decide whether to approve the BNG Plan within eight weeks. They must notify the applicant of their decision. If the LPA approves the BNG Plan, they must publish the decision on their planning register. Developers cannot start work on a development until the LPA has approved the BNG Plan.

LAs must report on BNGs that are delivered and expected to be delivered. Information from biodiversity metric calculations could support the duty to report on biodiversity gains.

NB: LPA entering into legal agreement

Before LPAs create a legal agreement, they must check:

• That the land manager has the right licences, consents and permits
• That the metric calculation for the habitat before creation and enhancement is accurate.

If the habitat or enhancement is within the wildlife consultation area of an aerodrome and that it does not harm aircraft operations.

Stage five: determination

After a LPA has received a valid planning application, it will undertake a period of publicity and consultation where views on the proposed development can be expressed. As part of this consultation, the information submitted as part of the application, including the minimum Biodiversity Gain information will be made publicly available for comment.

BNG will be a material planning consideration, so an appropriate delivery strategy will be considered. LPAs should consider how BNG condition can be successfully discharged.

Breach of planning control and completion 

Stage six: consideration of completion

The maintenance of a significant on-site habitat enhancement must be secured by either a planning condition, a planning obligation or conservation covenant for at least 30 years after the completion of development.

LPA should work with its applicants to clearly establish the point of completion for when the period begins. For the purposes of defining ‘completion’ for the purposes of BNG, LPAs are encouraged to include the completion of any on-site habitat enhancements (not just the buildings related to the development) which would constitute development. The use of traditional indicators of completion for residential or commercial development (such as a building regulations notice) may not be appropriate for the formal ‘completion’ of the development (i.e. when the final unit is completed) for the purposes of these provisions.