Biodiversity Net Gain FAQs - Frequently Asked Questions

This page is part of a set of resources PAS is working on to help local authorities implement mandatory biodiversity net gain. You can find links to these resources via our front 'BNG for local authorities' page. We also have a BNG practitioner network for local authority officers with an online forum and regular meetings: fill in this form if you would like to join.

Government has published a set of BNG guidance. We will be adding to these FAQs to cover questions asked since then in due course.

Biodiversity net gain (BNG) is an approach to development, and/or land management, that aims to leave the natural environment in a measurably better state than it was beforehand.

The Environment Act sets out the following key components of mandatory biodiversity gain:

• Amends Town & Country Planning Act (TCPA);
• Minimum 10% gain required calculated using the Biodiversity Metric & approval of a biodiversity gain plan;
• Significant on-site habitat and all off-site habitat secured for at least 30 years for at least 30 years via conditions, planning obligations or conservation covenants;
• Delivered on-site, off-site or via a new statutory biodiversity credits scheme; and
• National register for net gain delivery sites.

It does not change existing legal protections for important habitats and wildlife species. It maintains the mitigation hierarchy of avoid impacts first, then mitigate and only compensate as a last resort. It will apply to Nationally Significant Infrastructure Projects (NSIPs) but not marine development.

The mandatory requirement came into place on 12 February 2024 for all Town and Country Planning Act development but exemptions and non-major development. BNG will be required for development not defined as non-major development from 2 April 2024. For more information see this Defra blog post and the Draft biodiversity net gain planning practice guidance (draft BNG PPG) Paragraph: 003 Reference ID: 74-003-2023. The delay to implementing BNG for non-major development is to lessen initial burdens and allow a longer period for developers and local planning authorities to adapt and prepare for the high volume for minor applications. Implementation for Nationally Significant Infrastructure Projects is planned for 2025.

This is covered in the Biodiversity Metric user guide:

• ‘On-site’ includes all land within the boundary of a project. In a planning context, this usually means within a red line boundary.
• ‘Off-site’ is all land outside of the on-site boundary, regardless of ownership.

Note that on-site does not include land within the ‘blue line’ boundary.

Demonstrating BNG requires an approach to measuring biodiversity. The Biodiversity Metric is a habitat based approach to determining a proxy biodiversity value developed by Natural England. The Biodiversity Metric is designed to provide ecologists, developers, planners and other interested parties with a means of assessing changes in biodiversity value (losses or gains) brought about by development or changes in land management. Mandatory BNG will require use of the latest version of the Biodiversity Metric. Mandatory BNG will require use of the statutory Biodiversity Metric, which has been published as a draft.

The biodiversity gain plan is a document which sets out how a development will deliver biodiversity net gain and allows the planning authority to check whether the proposals meet the biodiversity gain objective.

The Environment Act sets out that development subject to mandatory BNG will be required to submit a biodiversity gain plan for planning authority approval and the planning authority required to approve it prior to commencement. This is required under the 'General condition of planning permission' added as Schedule 7A to the Town and Country Planning Act 1990 (under Schedule 14 of the Environment Act). Further information on the Biodiversity Gain Plan is set out in Paragraph: 029 Reference ID: 74-029-2023 onwards of the BNG PPG.

The Environment Act makes provision for the Secretary of State to set up a system of statutory biodiversity credits that will be invested in habitat creation. The biodiversity credits scheme allows the UK government to sell biodiversity credits to developers if the required biodiversity net gains cannot be achieved on-site or through the off-site market. The price of biodiversity credits are set higher than prices for equivalent biodiversity gain on the market. Natural England will sell statutory biodiversity credits on behalf of the Secretary of State. An accessible and user-friendly digital sales platform is currently being developed and tested. Further information is available in Defra’s Statutory biodiversity credits guidance.

The Environment Act includes provision to exempt irreplaceable habitats from the mandatory BNG requirement and these are set out in the Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations 2024. Further information on BNG and irreplaceable habitat is available in this Defra blog. 

The Environment Act has an 'extent' section which sets out which parts of the Act apply across Britain. The BNG provisions only apply to England via Schedule 14. CIEEM have published a briefing note for Scotland see: Biodiversity Net Gain in Scotland: Briefing Note for Local Planning Authorities.

The approach and metric for marine habitats and environments is not as developed as the terrestrial version. Defra published its response to the consultation on the Principles of Marine Net Gain in December 2023.

The Government has committed to funding all new burdens on local authorities arising from the Environment Act and Defra is working with DLUHC on the new burdens process. Government has provided transitional funding for LPAs to prepare for mandatory net gain up to the end of the 2023/24 financial year. Further funding beyond the current grant period will be confirmed in due course. The figure outlined in the 2019 net gain impact assessment is being revisited by Defra in recognition that things have changed since 2019. The funding has been estimated based on the additional burden from mandatory biodiversity net gain. 

PAS has published a short guide on resourcing BNG to help local authorities understand the skills and expertise they are likely to need to meet the requirements of mandatory BNG. It also provides examples of how local authorities can best secure natural environment skills and expertise. It has been developed with our BNG local authority officer advisory group and the Association of Local Government Ecologists (ALGE) and is available here. PAS has been funded by Defra to provide guidance and training for LPAs to enable them to be 'day 1 ready for mandatory BNG'.

Essentially the 10% set out in legislation is mandatory and therefore there is no scope for LPAs to reduce the requirement based on viability or other issues. Further information on Local Plans and BNG is available in the draft BNG PPG Paragraph: 005 Reference ID: 74-005-2023. Paragraph: 017 Reference ID: 74-017-2023 covers how existing local policies apply following the introduction of mandatory biodiversity net gain. 

There are good reasons to include BNG policies in Local Plans to support implementation and further information on this, along with examples of good locally-specific policies, are on our Biodiversity Net Gain in Local Plans and Strategic Planning webpage. We will also have examples of developer guidance and advice notes that some LPAs are using where their current Local Plan does not cover net gain on our Biodiversity Net Gain in Development Management webpage. In addition, Section 4.2 of the CIEEM/IEMA/CIRIA Biodiversity net gain good practice principles for development covers evidence gathering and provides further detail on types of evidence and links to good practice, whilst Sections 4.6 and 4.7 cover policy development.

Any requirements above the mandatory 10% would need to be set out in policy in the Local Plan and the Local Plan deemed sound, i.e. viability tested and the BNG target checked against other policies in the plan. Further information on BNG in new plans is available in the draft BNG PPG Paragraph: 005 Reference ID: 74-005-2023. See our Biodiversity Net Gain in Local Plans and Strategic Planning webpage for more information on assessing plan viability for BNG above 10%.

See our Biodiversity Net Gain in Local Plans and Strategic Planning webpage for more information on assessing plan viability for BNG above 10%.

Mandatory net gain, informed by the Biodiversity Metric, will be a minimum requirement for applicable development types. Any local policy will need to achieve this minimum but can work alongside the mandatory requirement. The mandatory requirement will also be in addition to the London Plan policies. It will be necessary for applicants to provide a Biodiversity Metric score and a UGF (Urban Greening Factor) score when applicable.

See the Greater London Authority’s Urban greening and BNG design guide for further information on how this can work.

For the same reasons why it is helpful to have a BNG policy in your Local Plan, it is also good practice to include neighbourhood plans, but no further guidance on this is available at present.

Government has confirmed that BNG is mandatory for major development from 12 February 2024 and for small sites from 2 April 2024.

Exemptions to BNG are set out in Paragraph: 003 Reference ID: 74-003-2023 of the draft BNG PPG.

The BNG requirement applies only to those applications submitted after BNG took effect on 12 February 2024 (or 2 April 2024 for small sites). For applications made under s73 of the Town and Country Planning Act 1990, BNG will not apply where the earlier permission was submitted or granted before the relevant date. This is set out in Paragraph: 003 Reference ID: 74-003-2023 of the draft BNG PPG. There are a couple of reasons for this:

1. BNG information will need to be provided at the applications stage to support an LPA to determine whether or not the BNG objective will be met. Accordingly, if this applied to all applications determined after 12 February/2 April 2024, there will be thousands of applications that would not include this information as it wouldn’t have been required beforehand.
2. While BNG is dealt with as a post-permission matter through the mandatory condition, LPAs need to have clarity on the BNG position prior to granting permission so that they can put in place necessary planning conditions and obligations to secure it (the aforementioned information will support with this).

DLUHC intends to amend the national validation requirements in the DMPO so that applications for BNG-eligible development proposals are accompanied by minimum national information requirements set out in the draft BNG PPG Paragraph: 009 Reference ID: 74-009-2023. Paragraph: 010 Reference ID: 74-010-2023 provides further information on local lists and BNG. Our BNG in Development Management Toolkit provides some thoughts on why local authorities and developers will probably want to go beyond the national minimum requirements.

Information on what is legally required at planning application stage and what further information may be needed to assist the consideration of biodiversity net gain as part of the planning application is set out in Paragraph: 009 Reference ID: 74-009-2023 of the draft BNG PPG. Our BNG in Development Management Toolkit provides some thoughts on why local authorities and developers will probably want to go beyond the national minimum requirements, especially in relation to understanding BNG being provided on-site.

Schedule 14 of the Environment Act sets out that a general condition will be applied to every planning permission (except those exempt from BNG requirements) that a biodiversity gain plan should be submitted and approved by the planning authority before commencement of development, specifically:

Every planning permission granted for the development of land in England shall be... subject to the [following] 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...

This means that a complete biodiversity gain plan will be required for all relevant development. It is important to note that the biodiversity gain plan must be submitted prior to commencement of development, but can not be submitted prior to the grant of permission. The draft PPG sets out more information on submission and approval of the biodiversity gain plan. 

BNG does not change existing protections, so current legal and policy provisions relating to development impacts on the natural environment, including protected sites and species, and priority species and habitats, all need to be considered in relation to habitat loss. A development cannot avoid this requirement by virtue of delivering a net gain. If there are protected species on-site then these should be approached and managed in the same way as they are currently. BNG and the Biodiversity Metric calculations would then be additional to this.

BNG just ensures that habitat is ‘valued’ in a way that it may not have been and that is at least replaced with a 10% extra. Assuming the habitat lost is not irreplaceable and the project is otherwise permissible, a LPA could not refuse planning permission based solely on the lifespan of a replacement habitat. Ultimately it is the LPA’s decision whether the biodiversity net gain information accompanying an application and the subsequent biodiversity gain plan is acceptable and whether to refuse or not on this basis, using the evidence submitted by the applicant, including on any locally distinctive habitats, to inform that decision.  The Biodiversity Metric also takes into account the risk of delay to the creation/ enhancement of habitat; so where a habitat is being lost and new habitat being created to replace it, this is more costly in terms of biodiversity units (and harder to reach 10%) than enhancement.  The LPA will need to be satisfied that the Biodiversity Metric has been used appropriately.

The Biodiversity Metric is a habitat-based approach, using habitat as a proxy for biodiversity. Species-based features such as bird and bat boxes are not included within the metric, instead it focuses on the habitats such species need to forage and complete their life cycles. The provision of such species features within developments should still be encouraged and LPAs can promote their usage through design guides and codes.

In relation to BNG, the Environment Act states that habitats should be secured for a minimum of 30 years: ‘habitat enhancement… will… be maintained for at least 30 years after the development is completed’. The 30 year term for biodiversity net gain isn’t meant to be regarded as in perpetuity – it was what was regarded as reasonable to ask for.

In some other cases, for example mitigation provided for sites or species protected under the Habitats Regulations, the requirement may be for management and maintenance of habitats ‘in perpetuity’. It will be up to the planning authority to determine the length of time that it is appropriate and reasonable to require ongoing management and maintenance of habitats as part of the grant of planning permission, taking into account the range of policy and legislative requirements, but the legal requirement for biodiversity gain habitats is 30 years as a minimum. Further information on BNG alongside other environmental payments is available in Defra guidance.

This is not set in legislation and will need to be assessed by LPAs as part of their planning approval process. The minimum viable area for particular habitats will vary depending on the habitats in question. Guidance available on delivering viable biodiversity improvements, including CIEEM’s Biodiversity Net Gain: Good Practice Principles for Development, A Practical Guide.

The biodiversity net gain approach embeds a fundamental principle for spatial hierarchy of habitat delivery, where there is a preference for onsite or local enhancements. Further information on this Biodiversity Gain Hierarchy is set out in the draft PPG Paragraph: 007 Reference ID: 74-007-2023. Our BNG in Development Management Toolkit provides some thoughts on applying the Biodiversity Gain Hierarchy at planning application stage.

The Biodiversity Metric incentivises habitat delivery on or close to the development site through a ‘Spatial Risk Multiplier’, which reduces the biodiversity value of habitats delivered further away from the development. 

Where a development cannot achieve BNG either wholly or partly onsite, then the developer can secure the unit shortfall by securing a bespoke site for net gain, or from appropriate sites on the local net gain habitat market from other landowners. These sites will need to meet the criteria of the biodiversity gain sites register (when available - see National biodiversity gain sites register below). If a shortfall in units required to achieve BNG remains, having explored the onsite and local offsite options, a developer can purchase statutory biodiversity credits from government as a last resort. 

PAS has some examples of conditions and S106s currently used by local authorities to secure BNG on our Biodiversity Net Gain in Development Management page and we will be providing some standard templates soon. Furthermore, PAS hosts a BNG Practitioner Network for LPA officers, which acts as a group to discuss and share documents and templates on BNG. If you wish to join this network, please fill out this Microsoft Form. For more information on securing off-site BNG, see Off-site BNG, BNG markets and habitat banks below.

Permitted development will not be required to deliver BNG under the Environment Act. However, the metric can still be used to quantify the losses and gains of habitat associated with the development activity and this is already being done by a number of developers for permitted development.

Mandatory BNG cannot be applied retrospectively for any applications approved before the legal requirements came in. However, BNG has been required in planning policy terms through the NPPF for a number of years, so this policy requirement is relevant for applications approved prior to the legal requirement coming into force.

Householder applications will be exempt from mandatory BNG. The BNG requirement will not be implemented until April 2024 for small sites and there is a Small Sites Metric available on the Biodiversity Metric webpage. The Small Sites Metric draft user guide sets out the circumstances under which it is appropriate to use this version of the Metric. Some information on applying BNG to small sites is provided in the Defra BNG guidance for LPAs.

You may also want to watch the recording of our ‘BNG: the essentials’ event held in November 2022, where David Warburton from London Borough of Sutton outlined how they are currently delivering BNG on small urban sites: Biodiversity Net Gain and Nature Recovery Autumn 2022 events | Local Government Association

An Overall Biodiversity Gain Plan that sets out how biodiversity gain will be achieved across the whole site on a phase-by-phase basis must be submitted to and approved by the planning authority before any development can be begun for outline planning permissions and phased development. Further information on applying BNG to phased development is provided in the draft BNG PPG.

The approval of reserved matters for outline planning permissions are not within the scope of biodiversity net gain (as they are not a grant of planning permission). 

Further information on BNG and minerals development is available in Paragraph: 056 Reference ID: 74-056-2023 of the BNG PPG.

Small-scale self-build and custom build development of no more than 9 dwellings and on a site which has an area no larger than 0.5 hectares is exempt from BNG. Larger scale outline applications should be dealt with in the same way as phased development. See the BNG PPG for more information.

Within Schedule 14 of the Environment Act, which sets out the biodiversity gain condition for development, measures are included that allow planning authorities to recognise any habitat degradation since 30th January 2020 and to take the earlier habitat state as the baseline for the purposes of biodiversity net gain. In order to ascertain the habitats present and their condition on 30th January 2020, aerial imagery or data sets from that time could be used. 30th January 2020 is the relevant date as it was the day the Bill entered Parliament.

For example, if a grassland site were strimmed or ploughed in July, the planning authority would be able to seek compensation for the habitat as it was in June, rather than the degraded habitat present in July. This system will take effect when the biodiversity gain requirement in the Environment Act is commenced.

Natural England and Defra intend to produce guidance on how this will work and which data sources may be of assistance in demonstrating the former value of any degraded or destroyed habitats. The 2022 consultation document sets out that further guidance within the Biodiversity Gain Plan will make provision for an earlier habitat value to be applied as the baseline where the value of habitats has been recently degraded.

If a site has a baseline biodiversity unit value of zero, then it would be exempt from mandatory BNG, but planning policy requirements for net gain would still apply. It would be advisable to calculate any biodiversity unit gains as a numerical unit value as opposed to a percentage. It will be at the discretion of the LPA to agree an appropriate number of biodiversity units to be delivered for the site in question on a site-by-site basis. Where a local authority knows that a number of development sites are likely to have very little to no biodiversity value or of a major allocation that fits this bill, e.g. urban, recently-previously developed land, they could consider setting expected unit gain values for these sites in Local Plan policy.  

It cannot be assumed that just because a site is small it has no baseline value. The baseline value reflects the ecological value of the pre-development site, not its size. Defra has committed to work with DLUHC to develop planning policy for minor development such as householder and de-minimis development, to seek to secure proportionate on-site biodiversity enhancements where possible.

This is provided for in the Environment Act, Schedule 14: Schedule 7A to the TCPA paragraph 5:

Pre-development biodiversity value

5(1) In relation to any development for which planning permission is granted, the pre-development biodiversity value of the onsite habitat is the biodiversity value of the onsite habitat on the relevant date.

(2)The relevant date is—

(a) in a case in which planning permission is granted on application, the date of the application, and

(b) in any other case, the date on which the planning permission is granted.

(3) But the person submitting the biodiversity gain plan for approval and the planning authority may agree that the relevant date is to be a date earlier than that specified in sub-paragraph (2)(a) or (b) (but not a date which is before the day on which this Schedule comes into force in relation to the development)

Circumstances under (2)(b) include things like Local Development Orders, Neighbourhood Development Order, Simplified Planning Zones, Enterprise Zones etc. BNG won’t be commenced for these routes in Spring 2024. Everything else is (2)(a), so baseline date is the date of application (not planning permission). 

Green Infrastructure (GI) can form part of BNG and pretty much all the most common GI features are captured within the metric and can contribute towards a BNG outcome. It is for the consenting body (LPA) to determine whether or not the proposal is appropriate (ecologically) or not. Horsham District Council have produced a Biodiversity and Green Infrastructure Planning Advice Note setting out how they consider BNG and GI in planning decisions.

BNG can be a sustainable, long-term funding stream for parks and greenspaces. GI strategies if published and agreed by the LPA can inform strategic significance scores in the Biodiversity Metric. See London’s Urban greening and BNG design guide for more information.

The Government’s 2023 BNG consultation response states that they will not make an exemption for development on statutory sites designated for nature conservation from the BNG requirement. They intend to use policy and guidance to prevent BNG being used as a justification for otherwise unacceptable development on such sites. See under ‘Additionality and stacking’ below for how SSSI enhancement can be counted for BNG.

Yes. Private gardens can make positive contributions to biodiversity, but appropriate planting and ongoing management can not be secured in the long-term. The Biodiversity Metric recognises this in its scoring of the value of gardens. See the Biodiversity Metric section for more information on this aspect.

Yes. See the Greater London Authority’s Urban greening and BNG design guide for further information on how this can work. Both scores will need to be submitted where applicable. One cannot be used as a proxy for the other policy.

Land used for off-site BNG delivery should be secured for the length of the net gain agreement, either via Section 106 agreements, or a conservation covenant. You will not need to have both in place to secure a site – just one of those two options. A conservation covenant is a private voluntary legal agreement, made in writing, between a Responsible Body and a landowner which establishes that land will be used for a conservation purpose. See Conservation Covenants below for more information. 

Our BNG in Development Management Toolkit provides an overview of the various BNG scenarios and how BNG might be expected to be secured both on- and off-site.

Further information on using S106 for BNG is provided in Paragraph: 026 Reference ID: 74-026-2023 of the PPG BNG and on enforcement in Paragraph: 006 Reference ID: 74-006-2023. For gains that are secured with conservation covenants, Government expects costs for monitoring and enforcement activities to be reflected in the price of biodiversity units. The responsible body for the conservation covenant will have responsibility for the enforcement.

Yes, BNG can be used to enhance local wildlife sites and local nature reserves. Defra will be providing guidance on the circumstances in which statutory protected sites can be enhanced for BNG.

Under the mandatory BNG approach, biodiversity units refer to the output of the biodiversity metric. The metric uses habitats and ‘biodiversity units’ as a proxy to describe biodiversity. These biodiversity units are the ‘currency’ of the metric. There are three types of biodiversity units, which are calculated in three separate ‘modules’ of the metric (area units, hedgerow units and watercourse units). Off-site biodiversity units can be sold, i.e. ‘1 unit of modified grassland costs £xx', but should not be referred to as credits to avoid confusion with statutory credits. Statutory credits are the last resort option for developers, if they can’t deliver the BNG they need onsite or via purchasing off-site biodiversity units. See Statutory credits scheme below for more information.

Habitat banking is an approach where investors pay landowners to increase the biodiversity value of their land and this uplift is then sold as units to those that need off-site biodiversity net gain. Often habitat is created in advance of units being sold meaning this is an ecologically beneficial approach. In practice, the term ‘habitat bank’ can either be used to describe:

• The parcel or parcels of land where the value of biodiversity is uplifted to provide off-site biodiversity units.
• The green finance approach where investors finance habitat restoration and creation and are rewarded with both monetary interest and environmental returns. See the Future Parks Accelerator resource for more information.

Under mandatory BNG, habitat created or enhanced after 30 January 2020 will be eligible for registration and sale of the associated biodiversity gains, provided it meets the other criteria of the biodiversity gain site register. Further information on habitat banking and BNG is provided in Defra’s Sell biodiversity units as a land manager guidance.

Local authorities will be able to use their own land to offer offsite biodiversity units to developers or act as a broker for third party units. When the mandatory BNG requirement comes into effect, this will need to be subject to the same confirmed rules and requirements for BNG as for other biodiversity unit providers, including registration on the Biodiversity Gain Sites Register. Local authorities will need to calculate appropriate biodiversity unit prices for offsite gains delivered on their land, or sold by them on behalf of a third party.  The prices will need to be sufficient to cover the costs of creating or enhancing the habitat and maintaining it for a minimum of 30 years.

Local authorities will not be able to direct developers to purchase biodiversity units from them in preference to other ecologically equivalent suppliers, and will be expected to manage any associated conflicts of interest.

Defra’s guidance for local authorities on BNG provides further information on off-site gains on land owned by a local planning authority. Freeths have written an article in Practical Law on how local authorities can create habitat banking mechanisms for BNG.

Any approach to the delivery of BNG (for developments where it is mandatory) will need to meet the minimum requirements as set out in the legislation (primary and secondary). This means that LPAs will not be able to levy a tariff system (i.e. a general fee) to then pool money for investment in nature elsewhere at some future point.  Offsite lands used for BNG must be registered on the biodiversity gain sites register, measured using a standardised biodiversity metric and legally secured for at least 30 years.

There is, however, scope to encourage the development of a local habitat bank (on LPA or other third party land) from which multiple developments could secure BNG through a single site through the sale of smaller parcels of biodiversity unit uplift (see above re schemes for local offsite delivery).

Yes. This is where having a Local Plan policy that links BNG to delivery of local strategic priorities is really helpful. See our Biodiversity Net Gain in Local Plans and Strategic Planning webpage for further information. See below for further questions on the national credit scheme.

No, this is not currently under consideration by Natural England or Defra.

Sellers will need to commit to managing the habitat for at least 30 years. They will need a planning obligation (section 106) with an LPA or a conservation covenant with a responsible body and are encouraged to agree an achievable habitat management and monitoring plan (HMMP) with them. Defra’s Legal agreements to secure your biodiversity net gain guidance sets out further information.

When securing gain sites, those involved should make sure that appropriate funding is in place for the duration of the agreement. Funds should be held for the duration of the agreement, should be held independently for large schemes and an appropriate payment schedule should be in place.

If a habitat bank provider can’t secure finance for the whole bank, they can still have plans in place for what they intend to do with the land but should only be entering land into conservation covenants/planning obligations if they have funding secured.

Defra can’t advise on specific financial arrangements but would suggest seeking independent advice. Government is also looking into options for a BNG assurance scheme.

Yes, it will be the developer’s responsibility to find a suitable location for off-site BNG delivery. This land will need to be legally secured and managed for the duration of the BNG period. Further information on the planning application process, including requirements for biodiversity net gain information at planning application stage, is set out in Paragraph: 009 Reference ID: 74-009-2023 of the BNG PPG. 

There is no requirement to hold a local register, although you may find it useful to do so. Some LPAs are setting their own requirements for landowners that want to feature on the ‘local register’.

Information on developers selling excess units is provided in Defra’s  Biodiversity net gain: what local planning authorities should do guidance.

If a Local Plan specifies a higher percentage than 10% then the LPA would need to consider whether the proposed approach is acceptable to them, as for any other local policy, through the planning application process for the later development(s).

Where units are being created in advance, they can be legally secured at the point of creation. The clock starts ticking for the 30 years once the habitat works have completed.  If these units are registered on the BNG register, this will provide assurance that the site is secured for 30 years following completion of the works. There will be no requirement to re-secure the units for another 30 years with another legal obligation when they are sold – the original creation date will apply. To approve the gain plan, the units must be registered on the offsite register.  The gain site must be registered, and the units allocated to the relevant planning permission prior to gain plan approval.

 Ideally they would have been created for BNG. They would need to meet with the combining payments guidance that ensures, for example, that they have not been paid for by a public grant and the land manager guidance which sets out additionality requirements, for example. that you cannot sell a woodland that has been required by a restocking notice.

It’s important to be aware that there are two different kinds of monitoring: habitat monitoring (the actual delivery of the habitat) which sits with the person creating, enhancing and managing the relevant habitat, i.e. the landowner/manager, who may also be (but is not always) the developer. Monitoring delivery of BNG sits with whoever has made the legal agreement with the landowner/manager to secure delivery of the habitat, i.e. a LPA for planning obligations and conditions or the responsible body for conservation covenants. Advice on monitoring BNG through the planning process is provided in Paragraph: 006 Reference ID: 74-006-2023 of the BNG PPG and there is a section on BNG monitoring in Defra’s guidance for LPAs. Our BNG in Development Management Toolkit provides an overview of the various scenarios for securing BNG and what role we think the LPA has in monitoring and enforcement for each of these.

Government encourages use of a habitat management and monitoring plan (HMMP) to capture management and monitoring information for significant on-site enhancements and off-site gains. Natural England have published a HMMP template and accompanying tools. They have also released a video explaining the HMMP template and how to use it.  Planning authorities are encouraged to set any specific and proportionate monitoring requirements as part of planning conditions and obligations used to secure off-site or significant on-site habitat enhancements. 

The planning obligations planning practice guidance states that LPAs can charge a monitoring fee for s106 obligations. BNG can pay for itself over time so LPAs can generate income through monitoring and pre-application fees. We have an online forum for the PAS BNG practitioner network, where officers are sharing how they are doing this, including costing monitoring. LPA officers can join by filling out this Microsoft Form. For conservation covenants, the price agreed for the units should include monitoring arrangements.

LPAs will have duties to report on BNG delivery under the Natural Environment and Rural Communities (NERC) Act. Government has published guidance on complying with the NERC duty and reporting on actions, including BNG.

In relation to BNG, the Environment Act states that habitats should be secured for a minimum of 30 years: ‘habitat enhancement… will… be maintained for at least 30 years after the development is completed’.

In some other cases, for example mitigation provided for sites or species protected under the Habitats Regulations, the requirement may be for management and maintenance of habitats ‘in perpetuity’. It will be up to the planning authority to determine the length of time that it is appropriate and reasonable to require ongoing management and maintenance of habitats as part of the grant of planning permission, taking into account the range of policy and legislative requirements, but the legal requirement for biodiversity gain habitats is 30 years as a minimum. Defra’s combining environmental payments guidance covers biodiversity units and nutrient credits, alongside other environmental payments.

The Environment Act states that significant increases from the on-site pre-development biodiversity value should be secured for at least 30 years. Defra’s Make on-site biodiversity gains as a developer guidance sets out some guidelines on what counts as a ‘significant’ enhancement. These gains will need to be secured through planning conditions, planning obligations or conservation covenants (or a combination of these methods). Defra’s guidance highlights that LPAs may also require legal agreements for wider planning policy reasons for other on-site enhancements or retained habitats which do not fall into the ‘significant enhancements’ category. In all cases, the LPA should be satisfied that the net gain condition to achieve a 10% gain will be met. Our BNG in Development Management Toolkit includes a presentation on On-site BNG which covers what PAS thinks in terms of when and how LPAs should secure on-site habitat.

Advice on enforcement of  BNG through the planning process is provided in Paragraph: 006 Reference ID: 74-006-2023 of the BNG PPG. Defra has produced guidance on Legal agreements to secure your biodiversity net gain. For gains that are secured with conservation covenants, Government expects costs for monitoring and enforcement activities to be reflected in the price of biodiversity units. The responsible body for the conservation covenant will have responsibility for the enforcement.

Incentives in the metric encourage gains to be located closer to the original impact location and the developer should demonstrate in the gain plan how they have applied the biodiversity gain hierarchy, i.e. avoid losses, if not possible mitigate and as a last resort compensate.

Our BNG in Development Management Toolkit outlines the main scenarios under which off-site BNG is provided and highlights that in PAS's view, it is likely that it is only where the off-site BNG will be secured through a S106 as part of the planning permission that monitoring and enforcement in relation to the planning permission will be required. If a developer buys units from another provider to meet the development's BNG objective, our view is that the responsibility for monitoring and enforcement of delivery sits with the LPA or responsible body that has the legal agreement with the provider, not the LPA for the planning permission.

The core purpose of the biodiversity gain site register is to record allocations of off-site biodiversity gains to developments and make this information publicly available. The register will not act as a marketplace platform for buying or selling units, nor will it assess the ecological suitability or additionality of proposals. 

This Defra blog provides further information on the statutory instruments for the register and Defra’s Sell biodiversity units as a land manager sets out how land managers register biodiversity units. Defra’s Biodiversity net gain: what local planning authorities should do  covers what LPAs should check on the register.

PAS has worked with Future Homes Hub on a BNG process flow showing the process through from pre-application to 30 years post-commencement and including the register. We will be updating this soon to reflect further information available now the BNG regulations and guidance have been published.

The 2023 BNG consultation response confirms that net gains delivered on site will not be required to be recorded on the national biodiversity gain sites register. Any off-site land used for the purposes of achieving BNG will need to be registered. Further guidance on how information on on-site gains in biodiversity gain plans can be recorded is expected to be published in Government guidance. The long-term ambition is to include on-site as well as off-site BNG delivery on the national biodiversity gain sites register, but there is no mandate for this under the Environment Act. 

There is no need to register off-site gains that were sold prior to commencement of mandatory BNG on 12 Febuary 2024.  

Natural England fully intends for the register to be up-and-running when BNG becomes mandatory. Defra is preparing a policy summary which will set out the intent of the register regulations. This will include information to be provided in an application to register land.

The national credit scheme will not allow for funds to be earmarked for a particular region.

This has not yet been decided and will depend on data received through Natural England's monitoring and evaluation programme. There may be some types of habitat that will always require statutory credits.

The credit price will be set to be intentionally uncompetitive with the market. Defra published indicative statutory biodiversity credit prices on 27 July 2023.

Credit sales revenue will be received by Natural England and invested in habitat creation projects. Natural England will be providing detail on the eligibility criteria of projects later in the year.

Revenue from credit sales will be invested in strategic habitat creation and enhancement which delivers long-term environmental benefits and is aligned with local nature recovery priorities

Government published guidance on combining environmental payments with BNG in February 2023. They also provided information on combining BNG with mitigation for protected species and protected sites in their 2023 BNG consultation response under Section 5.6 Additionality. You can also view the slides and recording from our deep-dive session on BNG and additionality in Spring 2022.

The current Natural England position is that it is possible to use sites delivering nutrient neutrality/SANG/GCN habitat to also deliver biodiversity net gain, on the basis that:

• Delivery of the non-BNG outcomes via habitat creation/enhancement could contribute up to a point equivalent to no net loss of BNG (as calculated by the Biodiversity Metric) but not beyond  – assuming they meet any other BNG requirements e.g. agreement type/duration etc.
• Additional habitat features created or enhanced on that same land beyond those delivered for the purpose of non-BNG outcomes could take you into positive BNG territory (again if measured and demonstrated using the metric) – assuming they meet any other BNG requirements e.g. agreement type/duration etc
• Good practice would be to illustrate BNG contributions derived from the above using a separate accounting line for transparency reasons. It is intended for this to be required in the biodiversity gain plan. Further details on this will be provided in the forthcoming BNG consultation.

So, habitats created for, and fulfilling the minimum requirements of, District Level Licensing for Great Crested Newts (DLL) could never get a project beyond a point of no net loss. The contribution to BNG through measures required as part of DLL is capped at a point equivalent to no net loss irrespective of the actual delivery outcome, as measured by the Biodiversity Metric. To achieve the required biodiversity unit uplift beyond no net loss to meet the BNG requirement, there must be habitat provision or enhancement beyond the minimum requirements of DLL.

Government will be providing guidance on the circumstances in which statutory protected sites can be enhanced for BNG and will keep this position under review through policy evaluation. Govt advice (as far as it goes) has been published here  Sell biodiversity units as a land manager (www.gov.uk) and says:

Selling biodiversity units on protected sites 
You may be able to enhance a protected site and sell the units for BNG. You must get consent from Natural England before you start work and renew consent as required. 
You must ensure that any protected species licences required are in place before works commence. 

Non-intertidal protected sites 
You can enhance features that are not specified as one of the designated features of the protected site. You must not do something which could adversely affect a designated feature and you must get consent before starting work. 

 
Intertidal protected sites 
You can enhance any intertidal habitat on a protected site, including the features for which the site is designated, provided this is acceptable to the consenting organisation. 
 

The current Natural England position is:

 Any compensation that a development is delivering in meeting wider statutory protections may be able to be counted towards that development’s BNG so long as it meets BNG criteria, for example,  legally secured for at least 30 years. However this would only count up to no net loss. 

The remaining 10% BNG units (or more if the Local Plan requires it) come from other additional activities. This would be subject to any relevant approvals such as SSSI consent or protected species licenses for the enhancement and only permitted where the proposals do not risk harming designated species or features.

The UK Land Carbon Registry is the database that stores and publicly displays data about the status of Woodland Carbon Code and Peatland Code projects and ownership and use of carbon units. You cannot stack carbon and BNG on the same land for the same activity (i.e. planting a woodland). You can only stack on top of carbon if you can further enhance the habitat and it does not affect the carbon value.

No, in accordance with the combining payments guidance, you can't sell biodiversity units where they have already been funded through public grant

Natural England’s recommendation would be that a separate accounting line is used, to ensure transparency and a clear audit trail in terms of evidencing the uplift in biodiversity unit value, i.e. The mitigation measures and the habitat delivering BNG is accounted for separately in the metric and any reporting.

Habitat works for mitigation purposes can count towards a no net loss, but could never on their own deliver a net gain. There would need to be habitat delivery over and above that required by the mitigation measures in order to count towards a net gain. 

Biodiversity Metric4.0 has been designed to work alongside the Environmental Benefits from Nature Tool (EBNT). EBNT provides developers, planners and other interested parties with a means of enabling wider benefits for people and nature from biodiversity net gain. The tool uses a habitat-based approach to provide a common and consistent means of considering the direct impact of land use change across 18 ecosystem service services.

For example, a user can run habitat data through the Biodiversity Metric in order to quantify any losses or gains in biodiversity unit value. They could then use that same data in the EBNT to calculate the wider ecosystem service benefits associated with the habitats (such as, carbon sequestration, recreational value and air quality benefits). 

Government published the statutory Biodiversity Metric tools and guides in November 2023. We do not have an up-to-date set of FAQs on the Biodiversity Metric.

We hosted introductory and intermediate training sessions on the Biodiversity Metric from Natural England and you can access the recordings and slides from these events for more information on the Biodiversity Metric. 

We hosted a Natural England training session on Biodiversity Metric 3 in October 2021 and we have posted questions and answers from that session with some updates in June 2023 to reflect more recent information on the event page.

Working with colleagues in the Environment Agency, we hosted some training events on the watercourse elements of the biodiversity metric in March 2023. The EA have shared a set of Frequently Asked Questions which are also available on our website.

The DEFRA evidence base and impact assessment considers that the 10% requirement is unlikely to significantly affect viability issues for development. DLUHC and Defra are not aware of any evidence to the contrary.  Essentially the 10% set out in legislation is mandatory and therefore there is no scope for LPAs to allow a reduction on viability grounds. If developers submit above 10% this is voluntary and anything above 10% would be subject to negotiation (and possibly would include viability justification) as part of planning application discussions with the LPA. If LPAs set the requirement higher than 10% in local policy, they would have to justify the level set in policy as part of their Local Plan process.

The following text extracted from the impact assessment highlights likely differences between impacts on developers:

We expect there will be a wide distribution of impacts, given that the costs and benefits will be highly dependent on the location and design of individual developments. In our analysis we assume that developers either: (1) already deliver net gain (entirely as we have proposed) or (2) do not deliver net gain (or even ‘no net loss’) and do little to mitigate or compensate habitat damage caused by their developments.

Given this, those currently doing the most to benefit the environment should find that this provides certainty. Since these developers already incur all or most of the costs of net gain, the most significant change for them (within our analysis) will be benefits associated with greater consistency in net gain within the planning process and greater consistency in expectations. The developers who currently cause high levels of environmental damage and do little to compensate for this will face the highest additional costs. This means, in practice, it is likely that the costs will fall unevenly across developers.

Biodiversity net gain should, therefore, steer development towards the least environmentally damaging areas and design practices. A significant proportion of costs imposed on developers are likely, in the medium to long term, to be ‘passed through’ to developable land prices, thereby affecting landowners.

In terms of costs to developers, the following conclusion is reached in the impact assessment:

Overall, the analysis indicates that net gain delivery costs are likely to be low as a proportion of key variables such as build costs and land prices. In addition, it is unlikely to lead to a significant increase on existing average developers contributions. While the analysis identifies regions where potential residential and non-residential viability issues may arise (e.g. Midlands, the North), this analysis is not a prediction of where site specific viability issues may arise in reality.

 For residential development costs to developers:

Our analysis demonstrates that, while there is a range of expected cost from delivery of net gain, relative to build costs they are relatively small for brownfield (between 0.1% and 0.8%) and greenfield (between 0.1% and 3.9%) developments. However, regions in the Midlands and the North have the highest potential costs as a percentage of build costs, but also have lower developable land prices which indicates potential for site specific housing viability issues.

And for non-residential:

The analysis shows that the majority of the costs across scenarios are expected to be less than 5% of land value, and that regions with higher costs (i.e. implying a potential site specific viability issue) tend to be in the North.

Local Plans, viability and percentage level of net gain

Our Biodiversity Net Gain in Local Plans and Strategic Planning webpage provides further information on assessing viability for net gain, including going above 10%.

For further information on nature recovery and Local Nature Recovery Strategies (LNRS), please see our Nature Recovery FAQs and overview webpages. LNRS Regulations and Statutory guidance for LNRS Responsible Authorities alongside a response to the 2021 local nature recovery strategies consultation were published by Government in April 2023.

The Environment Act contains a specific duty on all public authorities to "have regard" to relevant Local Nature Recovery Strategies (LNRS) and the LNRS regulations create a “supporting authority” role for local authorities, national park authorities and Natural England. Further information on this role is available in the Government’s response to the 2021 local nature recovery strategies consultation and PAS has published Local Nature Recovery Strategy frequently asked questions (FAQs).

Guidance is due to be published on the role of LNRS in the planning system. The expectation is that LNRS will be used to help inform how and where biodiversity net gain should be delivered, i.e. which habitats are appropriate in what locations. In particular, LNRS can be used to target offsite BNG so that it contributes to the Nature Recovery Network and the LNRS can be used as to determine the ‘strategic significance’ score that is part of the Biodiversity Metric scoring approach. The ‘strategic significance’ score is a landscape scale factor, which gives additional unit value to habitats that are located in preferred locations for biodiversity and other environmental objectives.

The expectation is that all local authorities will be involved in the development of LNRS, so it should reflect local priorities. Locally-specific plan policies could specify how the LNRS will be used to influence BNG delivery in a district, such as targeting of offsite BNG delivery and in Biodiversity Metric ‘strategic significance’ scoring.

Local authorities can use other local strategies to inform offsite targeting prior to implementation of LNRS, such Green Infrastructure strategies and biodiversity opportunity mapping. The availability and type of strategies available locally varies according to what activity and policy has been taken forward by local authorities, non-governmental organisations and other agencies. Where a Local Nature Partnership (LNP) is active, they are likely to have a mapping resource that can be used in advance of LNRS in locally-specific plan policies and to inform offsite targeting and determine ‘strategic significance’.

Buckinghamshire Council has prepared Interim BNG Strategic Significance and Spatial Risk Guidance and the Council plan to signpost to the LNRS when complete. Greater Cambridge Shared Planning Service has also prepared an Interim Offsite BNG Protocol setting out their expectations for off-site BNG delivery.

More detailed FAQs on conservation covenants are available alongside the slides and recording from the session on applying to be a conservation covenant responsible body PAS hosted in August 2023. Further information on conservation covenants is available on the Government website here. You can also access the slides and recording from a previous session on conservation covenants in June 2022. For further questions about conservation covenants please contact Defra via this mailbox: [email protected].

It is an agreement between a landowner and a designated “responsible body” such as a conservation charity, public body or for-profit body which conserves (protects, restores or enhances) the natural or heritage features of the land. It is a private, voluntary agreement made for the public good, which can continue to be effective even after the land changes hands.

The conservation covenant provisions (Part 7 and Schedules 18-20) of the Environment Act 2021 commenced in the autumn of 2022. Defra published guidance on how to apply to become a responsible body in July 2023 and we hosted a session with them in August 2023.

Conservation covenant guidance is available on the Government website and Defra published guidance on criteria for becoming a responsible body in July 2023. You can access the slides and recording from the session on applying to be a conservation covenant responsible body PAS hosted in August 2023.

Now the criteria against which applicants will be assessed have been published, organisations are able to apply to be responsible bodies. This includes local planning authorities that wish to take on the role.  Once organisations have been designated, they will then be able to start agreeing covenants with landowners.

Conservation covenants are a possible tool to secure biodiversity gains – and are specifically referred to in the net gain clauses in the Environment Act. We expect this will make them a valuable tool for local authorities and developers to ensure that compensatory habitats are maintained in the long term, even if the relevant land is sold.

The use of conservation covenants under mandatory net gain will be subject to certain conditions such as land under agreement being maintained for at least 30 years to help ensure delivery of net gain outcomes. Defra’s Legal agreements to secure your biodiversity net gain guidance provides information on the use of conservation covenants for BNG.

No – they can become responsible bodies if they want to. The session on conservation covenants & applying to be a Responsible Body in August 2023 and session on conservation covenants PAS hosted in June 2022 provide some more information on why a local authority might want to become a responsible body. If you want to legally secure your own land for BNG delivery you will need to register this with another Responsible Body through a Conservation Covenant as you can't have a legal agreement with yourself. LPAs like Buckinghamshire Council are looking at agreeing S106s with some potential habitat banks in their authority area but awaiting details of Responsible Bodies for their own land. LPA's cannot have a S106 agreement with themselves so this can’t be used where the LPA wants to buy units from its own habitat banks.

A responsible body can be:

• a local authority
• a public body or charity, where at least some of its main purposes or functions relate to conservation
• a private sector organisation, where at least some of its main activities relate to conservation

Who takes on the role of responsible body depends on what the arrangement is but a conservation covenant must be between a responsible body and a landowner. It is up to the organisation involved if they want to apply to register and take on that role. In conservation covenant terms, they would need to apply to be a responsible body, be accepted and then agree to take on that role with the relevant landowner.