Habitat banks and buying off-site biodiversity units

A habitat bank is a parcel of land where habitat is created or enhanced, secured for at least 30 years, and registered so that the biodiversity units it generates can be allocated to development elsewhere. The mechanism sits in Schedule 7A to the Town and Country Planning Act 1990, inserted by the Environment Act 2021, and the units are recorded on the biodiversity gain sites register. Buying units means buying an allocation on that register, backed by a legal agreement, and the quality of the paperwork matters more than the price per unit.

Developers approach this as a procurement exercise. It is closer to a land transaction, and the failure modes look like conveyancing failures rather than purchasing ones.

What a habitat bank is

Physically, a habitat bank is land where a landowner has committed to create or enhance habitat and to manage it for a defined period. Commercially, it is a supply of units that can be sold to developers who cannot deliver their whole gain on site.

The distinguishing features are the length of the commitment, the legal instrument securing it, and the registration. Land where someone has planted a hedge with good intentions is not a habitat bank. Land secured by a conservation covenant with a responsible body, or by a planning obligation, and entered on the register, is.

The units are calculated using the statutory biodiversity metric, which must be completed by a competent person. A bank's headline unit figure comes from that calculation, and the assumptions behind it are what you should be reading.

The biodiversity gain sites register

The register records gain sites, the habitat enhancement they will deliver, the legal arrangements securing it, and the allocation of units to particular developments. Allocation is the step that ties units to your scheme.

Two points matter for programme. Units cannot be allocated to a development that has not been identified, so the sequence runs from permission through the biodiversity gain plan to allocation. And once units are allocated to one development they are gone, so an option or reservation agreement with the bank is what protects you between agreeing a price and completing.

Check the register entry yourself rather than relying on a brochure. The entry states what has actually been secured.

Conservation covenants and section 106 agreements

Two instruments secure a habitat bank for the required period.

A conservation covenant is an agreement between a landowner and a designated responsible body, binding the land for the stated period, created under the Environment Act 2021. It runs with the land and survives a sale.

A planning obligation under section 106 of the Town and Country Planning Act 1990 can do the same job where a local planning authority is the counterparty, and it is the more familiar route for authorities.

Either way, read the agreement. The questions are whether the management obligations are specific enough to be enforced, who monitors and reports, what happens on a breach, and who carries the cost if the habitat fails to reach its target condition. A management plan referenced but not appended is a weakness.

How units are allocated to a development

The biodiversity gain plan submitted to discharge the gain condition sets out the on-site gain, any off-site gain and any statutory credits. Off-site units have to be registered and allocated before the authority can approve the plan.

That creates a practical sequence:

1. Complete the baseline metric and the post-intervention metric for the development.
2. Establish the residual shortfall after on-site delivery.
3. Identify a bank whose habitat types satisfy the trading rules for that shortfall.
4. Agree terms and secure an option or reservation.
5. Submit the gain plan, with the allocation confirmed on the register.

Trading rules constrain step three. Losses of higher distinctiveness habitat must be compensated with the same habitat type or better, so a shortfall in a specific habitat cannot be met with whatever units are least expensive.

Spatial risk and unit choice

The metric applies a spatial risk multiplier to off-site units, reducing their value as the compensation moves further from the impact. Units inside the same local planning authority area or national character area carry the full value, units in a neighbouring area are discounted, and units further away are discounted more.

The arithmetic follows. Buying 10 units in a neighbouring area does not deliver 10 units to your plan. Ask the bank for the figure after the multiplier has been applied to your development, not the gross figure for the site.

Strategic significance pulls the other way, so a bank inside an area identified in a local nature recovery strategy generates more units per hectare than an identical site outside one. The two multipliers interact, and the only reliable answer comes from running the metric with your own site and the candidate bank together.

Statutory credits as a last resort

The government sells statutory biodiversity credits, and the pricing is deliberately set to make them the option of last resort rather than a routine alternative to the market. Verify the current credit prices on gov.uk before relying on them in an appraisal.

Credits have one advantage. They are always available, which makes them a useful ceiling on what the off-site market can charge you and a fallback where no suitable bank exists for an unusual habitat type. Treat them as insurance rather than as a plan.

Due diligence before buying

Work through this list before signing anything.

• The register entry, checked directly, including the habitat types, the units available and any existing allocations.
• The metric behind the unit figure, including the baseline condition assessment and the target condition assumed.
• The trading rules check against your own shortfall, habitat type by habitat type.
• The spatial risk multiplier applied to your development, with the net units stated.
• The legal instrument, its duration, the monitoring regime and the remedies on breach.
• The management plan, appended and specific, with a named party responsible and a funding mechanism.
• What happens if the habitat fails to reach target condition, and who bears that risk.
• Title and any competing interests in the land, including mortgages and existing agreements.

The risk allocation clause is the one that separates a well run bank from a weak one. Habitat creation does not always work, and an agreement that leaves the developer exposed to a failure 15 years from now is not the same product as one where the bank carries it.

Ask, too, whether the units are already allocated to another development. It happens, and the register is the place to check.

Where this sits in the application

None of this removes the requirement for the statutory metric to be completed by a competent person or for the biodiversity gain plan to be approved by the local planning authority before development begins. A draft can structure the supporting documents and set out the method, and the report types show what each one covers, but the calculation and the professional judgement sit with the ecologist.

Contested classification questions in ecology behave much like those in other disciplines, from best and most versatile agricultural land to heritage. Evidence, documented, beats assertion. To scope the wider evidence base for a site, enter your postcode on PlanScope.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required. This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.