BNG Units For Sale

Who can purchase BNG units?

There are three main markets for BNG units:

• Mandatory: for residential, commercial and infrastructure developers to meet their BNG requirements under the Environment Act 2021.
• Voluntary: For companies (usually corporates) to help them meet their Environmental, Social, and Governance (ESG) targets, supporting the environment through nature recovery.
• Individuals: For people who are looking to personally invest in enhancing the natural environment.

The mandatory BNG market in England arose because of the Environment Act 2021, which made BNG a legal requirement for most new developments. This applies to major developments from February 2024 and small sites from April 2024.

Developers must achieve at least a 10% measurable biodiversity net gain. Some Local Planning Authorities may also have policies requiring more than 10%, which must be considered.

Planning permission is contingent on the submission and approval of a Biodiversity Gain Plan by the Local Planning Authority, outlining how the BNG requirement will be met.

The voluntary BNG market operates independently of statutory planning requirements. It serves businesses and organisations that wish to invest in nature recovery and biodiversity enhancement as part of their broader Environmental, Social, and Governance (ESG) strategies.

By investing in voluntary BNG units, often known as ‘credits’ in this market, companies contribute directly to local and national nature recovery efforts, beyond what is legally mandated, showing a proactive commitment to a greener future.

The individual market for BNG units allows private individuals to invest directly in large-scale nature restoration. This market provides a powerful avenue for them to personally support nature recovery, contributing to projects that increase biodiversity, restore ecosystems, and help mitigate climate change.

Purchasing BNG units for mandatory purposes involves a structured process:

A qualified ecologist will first assess the ecological baseline of your site using a Biodiversity Metric to determine the existing biodiversity value and calculate the number and type of units required for your project to achieve 10% BNG.

The process for developers follows a "mitigation hierarchy" to minimise biodiversity loss. In order of preference, this hierarchy is:

• Avoid: Design development to avoid impacts on biodiversity as much as possible.
• Minimise: Reduce unavoidable impacts.
• Mitigate: Compensate for impacts on-site within the development boundary.
• Compensate: (Off-site): If BNG cannot be fully achieved on-site, off-site units can be purchased from landowners or specialist providers like Halnaker Hill Farm, who have created or enhanced habitats for this purpose.
• Statutory credits: As a final option, if BNG cannot be achieved on-site or through the off-site market, developers can purchase statutory biodiversity credits from Natural England. These are intentionally priced higher to encourage on-site and off-site market solutions.

This hierarchy does not apply to companies or individuals wishing to purchase BNG units voluntarily – in those cases, it is possible to directly approach a biodiversity bank such as Halnaker Hill Farm to buy units.

The process is as follows:

• Developers identify their off-site unit requirement
• Explore on-site mitigation measures
• Enquire about purchasing required units from habitat bank registered with Natural England or, if not possible, buy statutory credits
• Secure purchase with allocation agreement
• The habitat bank will register the allocation agreement with Natural England

Initial enquiry – begin by sending project information and your biodiversity requirements, usually set out in the biodiversity metric and supported by an ecological report, to a landowner, broker or BNG provider who will review these details and may arrange a discussion to clarify your needs.

Proposal and agreement – the BNG provider issues a proposal that outlines the number and type of units required, associated costs, timescales, and recommendations to fulfil the purchaser’s biodiversity requirements. If you are happy with the offer, confirm that you wish to proceed.

Allocation Agreement – the purchase of BNG units is secured through an allocation agreement, which is the legal agreement documenting the number and type of units being purchased as well as clearly setting out the associated costs and obligations for both the purchaser the seller.

Final agreement – once the allocation agreement has been signed and the appropriate payments have been made, the habitat bank will officially register the allocation of the agreed BNG units with Natural England. The allocated units will then appear on the Natural England biodiversity gain sites register confirming the allocation has formally been registered. From that point, the BNG provider takes responsibility for the long-term management, monitoring, and compliance of the units.

Reserving units – in some instances you may wish to secure BNG units well in advance of requiring them, eg. ahead of securing planning consent, so that you know the units you require will be available once planning permission is granted. Some habitat banks, Halnaker Hill Farm being one of them, will gladly enter into a purchase agreement to secure the future purchase of units. A deposit secures the units and confirms the purchase agreement. The length of time the units will be held for the purchaser will be agreed in the purchase agreement.  

Final allocation – once planning permission is granted and the purchaser would like to complete the purchase of the BNG units, the final balance is paid and the habitat bank will officially register the BNG units and link them to the development through the national register.

The metric accounts for the following three risk factors:

• Delivery difficulty – how difficult the habitat type is to create or restore/enhance
• Temporal risk – time to target condition (i.e. how long the habitat type takes to establish and reach a targeted condition)
• Spatial risk – the distance between the site of habitat loss and the site where creation/enhancement is provided

The higher the risk factor, the more biodiversity units will be required for offsetting.

For off-site units, you would typically engage with brokers or directly approach habitat bank providers like Halnaker Hill Farm. To enquire with us, use our contact form here.

Once you identify a suitable habitat bank that can fulfil your purchase requirement, make sure to check the habitat bank is registered with Natural England on the biodiversity gain sites register. Check here.  

BNG units can only be purchased from habitat banks registered on the biodiversity gain sites register.

As part of a planning application, a Biodiversity Gain Plan is submitted to the Local Planning Authority (LPA), detailing how BNG will be achieved, including any off-site unit purchases and their registration numbers. This plan must be approved before development can commence.

For voluntary or individual purchases, the process can be simpler, involving direct engagement with providers to agree on the units, their allocation, and the terms of investment for your specific goals.

A Habitat Management and Monitoring Plan (HMMP) is a detailed document that sets out how a habitat enhancement or creation project will be managed and monitored over the minimum 30-year period required for BNG.

The HMMP outlines:

• Specific management interventions (e.g., planting, weeding, grazing regimes).
• Ecological targets to be achieved.
• A monitoring schedule to assess progress towards those targets.
• Contingency plans in case targets are not met.

The HMMP is a crucial component of the legal agreement (Section 106 or Conservation Covenant) that secures the BNG units, ensuring the long-term success and ecological integrity of the compensatory habitats.

All off-site BNG sites and allocated units* are listed on the public Biodiversity Gain Sites Register, providing transparency and traceability for developers and planning authorities. Developers, local planning authorities, and other interested parties can use the register to:

• Verify the existence and details of registered biodiversity gain sites
• Confirm that BNG units from a specific site have been allocated to a particular development

This register ensures transparency and accountability in the BNG market, making it easier to track the delivery of biodiversity net gain across the country.

*The register will only accept allocations made using the Statutory Metric.

The habitat bank provider is responsible for providing habitat monitoring reports to the local planning authority (LPA)/responsible body throughout the scheme period. At Halnaker Hill Farm we are registered with the South Downs National Park Authority as our monitoring LPA.

The habitat bank provider is responsible for applying for allocations of biodiversity units to be registered with Natural England.

Off-site BNG units must be legally secured for at least 30 years through a Section 106 Agreement with the local planning authority or a Conservation Covenant with a responsible body. This agreement ensures the long-term management and monitoring of the habitat.

Whether you are considering purchasing for a developer or company, or interested in BNG as an individual, we would be pleased to hear more about your requirements. Contact us here and we’ll be in touch.