ACP Insights & Guidance
Off-site BNG allocation needs a clear evidence trail. Use this guide to connect the recorded allocation with the planning permission, statutory metric and biodiversity gain plan before submission.
The practical answer
Keep purchase records, registration details and allocation evidence distinct. Then check that the accepted allocation supports the development and assessment named in the gain plan.
Purchase, registration and allocation are different
Off-site BNG allocation connects registered biodiversity gains to the development that will use them. A quotation, reservation or payment records a commercial arrangement. However, it does not demonstrate that the biodiversity gain sites register records the allocation.
Registration identifies the gain site. Allocation records gains against a development with planning permission. Applicants can request registration and allocation together, or request allocation after registration. The commercial purchase can occur at different points, so avoid treating one purchasing timetable as universal.
For a development relying on off-site gains, the register must show the allocation before the authority can approve the gain plan. Confirm the planning route and any phased-development requirements with the project team. See the government guidance on making off-site gains as a developer.
Follow the evidence into the gain plan
- Confirm the requirementThe ecologist identifies the unit types and quantities needed using the current development assessment.
- Identify the gain siteThe provider supplies the site reference and the relevant registration position.
- Verify recorded allocationThe authorised applicant supplies confirmation linking the appropriate gains to the development.
- Reconcile the submissionThe coordinator checks the evidence against the gain plan, metric and planning documents.
First, agree who will obtain each record before setting a submission date. Keep preliminary offers, submitted applications and accepted records in separate folders. An application awaiting a decision should remain clearly labelled as pending.
ACP explains the wider routes through off-site biodiversity units and biodiversity gain-site registration. This checklist focuses on the development evidence bundle.
Build an allocation evidence register
Next, create one index that points to the authoritative files. Record the document name, author, issue date, revision, location and reviewer. The roles below are suggested coordination roles; agree the actual owners for your project.
| Record | Check and action |
|---|---|
| Planning permission | Planning lead: identify the permission, application reference, development description and any relevant phase. Keep the approval notice with the submission records. |
| Development boundary | Design lead: identify the current red-line plan and relevant phase drawings. Ask the ecologist to review changes affecting the assessment. |
| Statutory metric | Ecologist: confirm the calculation version, plan references, required unit types and quantities, and the off-site inputs used. |
| Gain-site reference | Provider or authorised agent: supply the unique registered site number. Distinguish it from a sales reference or the provider’s internal plot name. |
| Allocation evidence | Applicant or provider: supply the accepted record identifying the development and allocated gains. Confirm that it supports the inputs used in the gain plan. |
| Gain plan and ownership | Planning lead: cross-reference the final evidence. Name the person resolving each outstanding query and the person authorising issue. |
Do not silently edit third-party documents to make references agree. Instead, request a corrected issue or a written explanation from the document owner. Also retain the original and the response so another reviewer can follow the decision.
Resolve mismatches before the next issue
For clarity, use a short discrepancy log with five fields: the mismatch, affected files, responsible person, required response and closure evidence. A status such as “email sent” describes activity, not resolution. Then close the item only when the appropriate reviewer accepts the response.
Worked example: a changed development description
The allocation evidence refers to an earlier scheme description, while the gain plan uses the approved wording. The coordinator records both references and asks the provider and planning lead to review the difference.
The ecologist also checks whether the change affects the metric inputs or unit requirement. The coordinator then files the agreed explanation or corrected evidence and records which gain-plan revision incorporates it.
If the proposal changes after the evidence is assembled, reopen the affected checks. Changes to boundaries, habitat impacts, phasing or the unit mix can require specialist reassessment. Document control can reveal a mismatch; it cannot decide whether a revised arrangement satisfies the project requirements.
Use a clear release check
- The submission identifies the permission and relevant phase consistently.
- The register names the current metric and plans by revision.
- The evidence supports the registered gain-site references and recorded allocations.
- Preliminary commercial records are distinguishable from accepted allocation records.
- Every discrepancy has an owner and a documented outcome, or remains visibly open.
- The planning lead and ecologist have reviewed the coordinated submission set.
Keep unresolved dependencies visible in the programme. Do not describe the bundle as complete simply because a purchase has been agreed. Equally, avoid duplicating legal or ecological checks that the appointed specialists already own.
Questions about off-site BNG allocation
Does buying biodiversity units mean they are allocated?
No. Purchase is a commercial step. Check separately that the site is registered and that the relevant gains are recorded as allocated to your development.
What should match the planning application?
Check the development identity, permission, relevant phase, plans and metric version. Where descriptions differ, obtain an explanation from the responsible advisers rather than rewriting supplied evidence.
What needs checking after the scheme changes?
Ask the ecologist and planning lead to review the changed proposal, metric and gain plan. Then confirm whether the allocation evidence or supporting documents also need updating.
Who should submit the register application?
Agree the responsible applicant or authorised agent with the gain-site provider. Follow the current government application route and permissions; a document coordinator should not assume they can act for the landowner.
References and scope
- Defra: Make off-site biodiversity gains as a developerExplains the relationship between purchasing units, recorded allocation and the biodiversity gain plan.
- Defra and Natural England: Register a biodiversity site and allocate to a developmentSets out the combined application route, eligible applicants and supporting information. Updated 2 June 2026.
- Planning practice guidance: Biodiversity net gainExplains the planning process, gain-plan approval and the treatment of phased development.
Sources checked 29 October 2026. This guide supports project coordination in England; apply the current documents and specialist advice for your scheme.