The Off-site BNG Marketplace

An overview of local authority interactions with the off-site BNG marketplace, including key insights on potential supply and demand for biodiversity units, regulating off-site proposals for the purpose of selling and supplying biodiversity units and working with Natural England’s Gain Site Register.


Overview

Local planning authorities across the country have undertaken substantial work to understand the level of supply of off-site biodiversity units that may be required from development in their area, identify future demand, and analyse existing land use to enable development alongside meeting BNG requirements. The off-site marketplace continues to be a prominent area of interest, and the PAS team has dedicated time to developing a ‘Market in Practice’ series, sharing insights from the viewpoint of local planning authorities collaborating with external stakeholders. 

Alongside this, the PAS team has brought together six case studies from councils across England, highlighting how authorities are responding to the evolving off-site biodiversity market. These examples illustrate the mechanisms councils are putting in place to support internal processes, manage risk, and regulate third-party providers seeking to supply and sell off-site biodiversity units within their areas.  

Councils are also proactively sharing learning and insights from their work regulating the marketplace. Somerset Council, for example, provides a useful webpage listing local habitat banks that have been secured through S106 agreements or conservation covenants. The Oxfordshire Local Nature Partnership also offers extensive guidance and information on local gain sites, including their voluntary NatureMark initiative, which has been designed to ensure quality, integrity and transparency for both buyers of biodiversity units and local communities.  

Through its pioneering Habitat Bank Regulation service, Buckinghamshire Council is helping deliver high-quality BNG. They have sites on Natural England’s national register: one is at Lopemede Farm. This is a compelling example of how local authorities and landowners can work together to deliver development that improves nature for the future. 

Future Homes Hub created a Biodiversity Offset checklist in June 2024. The checklist can be used by developers to give them confidence that their chosen offset provider has, or will be developing, a credible biodiversity offset if it has not yet been legally secured or registered. They also have a unit finder tool to connect stakeholders looking for off-site biodiversity units.

Natural England's Gain Site Register

Government guidance is available to support land managers looking to sell off-site biodiversity units to developers, as well as on registering and recording gain sites and allocations on Natural England’s gain site register. The register allows users to view registered sites and check how off-site biodiversity units have been allocated to planning applications. 

Natural England’s role as administrator of the gain site register does not involve checking statutory biodiversity metrics associated with gain sites or planning applications. Their responsibility focuses on scrutinising the legal agreements, site ownership and management of the proposal. 

The following content addresses the questions raised during the July 2025 session with Natural England’s Gain Site Register Team.

Local authorities adapting to the off-site market

This document showcases the different approaches taken by three Local Authorities across England to bring their own land into the off-site biodiversity unit market, allowing them to secure environmental benefits by implementing off-site BNG on land under council ownership.  

These are shared to provide example approaches for other local authorities looking to bring their land forward to market and exploring ways to generate and supply off-site biodiversity units. It is particularly relevant for asset managers evaluating council-owned vacant land or green space for its potential for off-site BNG.  

We looked at approaches to investment in local nature via nature-related projects or improvements to environmental management by Plymouth City Council, Greater Manchester Combined Authority and Coventry City Council. 

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Each case study illustrates how the approach: complements local policy; addresses off-site market demand; considers and manages risks associated with establishing a gain site; establishes management actions over the project lifetime; and integrates the processes of operating in the off-site market within local authority operations.  

Key actions taken in each case include: 

  • Setting up an arm’s length special purpose vehicle to generate and trade biodiversity units.
  • Using an impact fund to facilitate the management of supply areas for biodiversity units and carbon credits.
  • Working collaboratively with partner organisations to identify local potential for natural capital.  

The key benefits of these actions include: 

  • Collectively generating additional revenue for local reinvestment.
  • Creating positive socio-economic and environmental impact for local communities in areas of deprivation.
  • Triggering innovative monitoring solutions for the long-term.
  • Allowing for precautionary risk management.
  • Allocating internal resources to support with maintaining long-term BNG.
  • Enhancing transparency for all stakeholders.
  • Creating local unit supply to mitigate impacts from local development proposals. 

This insight document sets out:   

Key takeaways include:  

Local authorities regulating the off-site market

This document showcases the different approaches taken by three local authorities in the South of England: Somerset Council, Buckinghamshire Council and Devon County Council to regulate and approve biodiversity gain sites as part of their strategy for providing local off-site solutions for BNG. These case studies look at the approaches taken by the authorities to review and approve landowner schemes for generating a supply of biodiversity units for new developments. Their approaches allow them to take a central role in the governance and regulation of new off-site solutions to BNG and other environmental schemes in the private marketplace.  

We highlight how each council’s approach complements local ambitions, addresses existing environmental concerns unique to each authority, considers opportunities for improving resourcing and costs, and influences the development of off-site solutions to mitigate environmental impacts.  

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The purpose of these case studies is to encourage other local councils to consider whether such approaches might be the right route for them. The case studies cover the following key actions:  

  • Setting up a habitat bank regulation service to review potential supply areas for biodiversity.
  • Using an environmental call for sites process.
  • Working with landowners on identifying the potential for maximising local ecosystem services. 

These approaches collectively, across the three local authorities: 

  • Contribute to the generation of additional revenue for resourcing and costs,
  • Have socio-economic and environmental benefits for local communities,
  • Encompass precautionary risk management, and
  • Influence supply within the private marketplace.

This insight document sets out:   

Key takeaways include: 

Market in practice

The PAS team is always interested in emerging BNG approaches, particularly where a local planning authority is trialling an innovative approach that supports, or is tailored to, its specific needs. Recordings from recent episodes in the series can be accessed below. We intend to continue developing this series, and any future episodes will be uploaded to YouTube and posted here. 

DISCLAIMER: The PAS team updates these pages regularly to reflect current guidance on biodiversity net gain as best we can. Our goal is to provide accurate, timely information to support local planning authorities. If you are from a local authority and have any questions about the content or need further information, please contact us at [email protected]. This page was last updated on 28/11/25.