An approved Biodiversity Gain Plan cannot simply be amended under the current Biodiversity Net Gain framework. If the approach to meeting the biodiversity gain objective changes after the plan has been approved but before development begins, a new Biodiversity Gain Plan can be submitted to the relevant planning authority for approval.
Changes to a development layout, post-development habitats or off-site biodiversity provision may also affect the Biodiversity Metric, meaning the project’s calculations may need to be reviewed before a replacement plan is submitted.
For developers, identifying these changes early is important. Starting development without the required Biodiversity Gain Plan approval, or proceeding in a way that does not comply with the approved BNG arrangements, can create planning and compliance risks.
Can an Approved Biodiversity Gain Plan Be Amended?
No. Government Biodiversity Net Gain planning guidance states that there is no mechanism for amending an approved Biodiversity Gain Plan.
If the way a development will meet its biodiversity gain objective changes after the plan has been approved but before development commences, a new Biodiversity Gain Plan can instead be submitted to the planning authority for approval.
For example, the government specifically identifies a change between registered off-site biodiversity gains and statutory biodiversity credits as a situation where a new plan could be required.
Developers should therefore avoid treating an approved Biodiversity Gain Plan as a document that can simply be edited and reissued.
Why Might a Biodiversity Gain Plan Need to Change?
A new Biodiversity Gain Plan may be necessary where changes affect how the development will achieve its required biodiversity gain.
This could arise because the development design changes, the proposed on-site habitat creation or enhancement is altered, or the project’s planned off-site biodiversity gains are no longer available.
Changes affecting the development footprint are particularly important because the statutory Biodiversity Metric compares pre-development biodiversity value with post-development biodiversity value.
If the approved layout changes which habitats will be retained, lost, created or enhanced, the post-development biodiversity calculation may also change.
The project team should therefore review the Biodiversity Metric alongside any material design changes rather than assuming the original BNG strategy remains valid.
Does the Biodiversity Metric Need to Be Recalculated?
The Biodiversity Metric should be reviewed where a proposed change affects information used in the approved calculation, including the post-development biodiversity value or the project’s off-site unit requirement.
The statutory Biodiversity Metric measures biodiversity value using factors associated with habitats, including their type, size, condition and strategic significance.
Changes to the development footprint or proposed habitat creation and enhancement can therefore alter the post-development calculation.
Importantly, once the pre-development biodiversity value has been established through an approved Biodiversity Gain Plan, that value does not change for that planning permission.
This means recalculation following a design change is not an opportunity to establish a different baseline. Instead, the project team needs to assess the revised proposals against the established pre-development value and determine whether the biodiversity gain objective continues to be met.
What Happens If the Development Layout Changes?
A development layout change should trigger a review of the approved BNG strategy where it affects habitats, biodiversity enhancements or the development’s post-development biodiversity value.
For example, a revised layout could increase the amount of habitat lost within the red line boundary, reduce space previously allocated for on-site habitat creation or alter a significant on-site habitat enhancement.
Any resulting change in post-development biodiversity value could affect how many biodiversity units are needed to maintain the required net gain.
The updated development may therefore need a revised biodiversity metric calculation and, where the approved approach to meeting the biodiversity gain objective has changed before commencement, a new biodiversity gain plan.
BNG should consequently be considered alongside design revisions rather than reviewed only after the wider planning changes have been agreed.
Can Off-Site BNG Units Be Changed After the Plan Is Approved?
Changing off-site BNG units after they have been purchased, registered and allocated to a development can be difficult. In practice, developers should treat an allocation as effectively final once it has been made, rather than assuming biodiversity units can easily be swapped or reallocated later.
The Biodiversity Gain Plan records the registered off-site biodiversity gains allocated to the development. Those units must correspond with the development’s biodiversity metric and satisfy the relevant habitat trading requirements.
Natural England’s guidance on amending an allocation of off-site biodiversity gains provides only limited circumstances in which an allocation can be changed. An application can be made to reduce the area or length of an allocated habitat or remove a recorded allocation entirely. However, an allocation cannot be amended while it relates to an existing condition of planning permission. Evidence must be provided showing that the planning permission conditions connected with the allocation are no longer in place before Natural England can consider the amendment.
The process also requires supporting information, including the statutory Biodiversity Metric for the allocated development reviewed by the approving local planning authority. Natural England advises that an allocation amendment application can take up to six weeks.
This means developers should be confident that the units they are purchasing are suitable before they are formally allocated. Habitat type, trading rules, spatial risk, the development’s Biodiversity Metric requirements and the availability of the units should all be considered before the allocation is finalised.
Securing appropriate off-site BNG units early can provide greater certainty over availability and cost, but the allocation itself should be approached carefully. Once units have been formally allocated to a development and are tied to its planning permission, reversing that decision is highly restricted rather than a straightforward administrative change.
What Happens If a New Biodiversity Gain Plan Is Required?
Where a new Biodiversity Gain Plan is required before commencement, it must be submitted to the relevant planning authority and approved before the development can begin under that permission.
The plan should reflect the updated approach to meeting the biodiversity gain objective and be supported by the appropriate completed biodiversity metric calculation and evidence.
Government guidance states that planning authorities normally have eight weeks to approve or refuse a Biodiversity Gain Plan unless a different timescale is agreed.
This makes the timing of revisions important.
Discovering shortly before the intended commencement date that a design or BNG delivery change requires a new plan can affect the development programme while the revised documentation is prepared and determined.
Developers should therefore identify potential changes as early as possible and discuss the appropriate route with the relevant planning authority.
What Happens If Planning Permission Is Varied Under Section 73?
A Section 73 application can introduce additional BNG considerations because permission granted under Section 73 is a new planning permission linked to the original permission.
Current Planning Practice Guidance contains specific provisions explaining how Biodiversity Net Gain applies to Section 73 permissions.
In some circumstances, an earlier Biodiversity Gain Plan can effectively carry across to the new permission. However, where conditions attached to a new Section 73 permission affect the post-development biodiversity value, a Biodiversity Gain Plan for the new permission must be submitted and approved before development under that permission commences.
The statutory biodiversity gain condition itself cannot be varied or removed through a Section 73 application.
Developers changing an approved scheme should therefore consider BNG at the same time as the planning variation rather than assuming the existing Biodiversity Gain Plan automatically remains suitable.
What Are the Rules for Phased Developments?
Phased developments have a different Biodiversity Gain Plan process. They require an Overall Biodiversity Gain Plan for the development and individual Phase Biodiversity Gain Plans before each relevant phase begins.
The government’s phased development guidance reflects the fact that large developments may evolve over a long period, and full details of later phases may not be known when planning permission is originally granted.
The Overall Biodiversity Gain Plan establishes the framework for achieving at least the required biodiversity gain across the development.
Each Phase Biodiversity Gain Plan then establishes how that individual phase contributes towards the overall objective.
This structure provides greater flexibility for long-term schemes, but changes still need to be assessed carefully against the approved overall BNG strategy, relevant phase plan and statutory Biodiversity Metric.
Can a Biodiversity Gain Plan Change After Development Has Started?
The government’s specific route for submitting a new Biodiversity Gain Plan where the BNG approach has changed applies to changes made after approval but before commencement.
Once development has commenced under an approved Biodiversity Gain Plan, developers should not assume the same process can be used to retrospectively replace the approved arrangements.
The approved plan forms part of the framework through which compliance with the statutory biodiversity gain condition is demonstrated. Other planning obligations and legal agreements may also secure habitat delivery and long-term management.
Where a change becomes necessary after commencement, the appropriate route will depend on the planning permission, the nature of the proposed change, any legal agreements and whether on-site or registered off-site gains are affected.
The developer should therefore engage with the relevant planning authority and appropriate ecological and planning professionals before departing from the approved BNG arrangements.
Do Habitat Management Agreements Need to Reflect BNG Changes?
Changes affecting significant habitat creation or enhancement may also have implications for the documents and legal mechanisms securing those habitats.
Significant on-site biodiversity gains and registered off-site biodiversity gains generally need to be secured for at least 30 years through the appropriate planning or legal mechanism.
For off-site habitat banks, this can include a conservation covenant or planning obligation such as a Section 106 agreement.
The Habitat Management and Monitoring Plan sets out how habitats will be established, managed and monitored over the required period and is likely to be referenced extensively within the legal agreement and appended as a key supporting document.
If the proposed habitat delivery changes, the project team should therefore consider whether the relevant management arrangements and legal documentation also need to change.
What Is the Planning Risk of Getting BNG Changes Wrong?
Proceeding without the necessary Biodiversity Gain Plan approval can create a compliance issue because the biodiversity gain condition is a pre-commencement condition.
For developments subject to mandatory BNG, planning permission is deemed to include the biodiversity gain condition. Development cannot begin until the Biodiversity Gain Plan has been approved.
Local planning authorities also have an ongoing role in ensuring that developers and land managers meet their BNG commitments. Government guidance confirms that failure to meet BNG requirements can lead to enforcement action where a developer is in breach of planning conditions, planning obligations or a legal agreement.
Failure to meet BNG requirements can lead to enforcement action where a developer is in breach of planning conditions, planning obligations or a legal agreement.
There is also a practical commercial and administrative risk. If a revised biodiversity metric creates a larger or different off-site requirement late in the process, developers may need to secure additional biodiversity units at short notice. Amending biodiversity units that have already been formally allocated is considerably more complicated. Changes to an original allocation can require approval from the relevant local planning authority and an application to Natural England to amend the allocation on the Biodiversity Gain Sites Register.
Natural England will not amend an allocation while it remains connected to an existing condition of planning permission, so the relevant planning position must first be resolved and appropriate evidence provided. Developers should therefore treat a formal allocation as effectively final and make sure the habitat type, number of units, trading rules and spatial requirements are correct before the allocation is completed.
Early review of the Biodiversity Metric and off-site requirements can help avoid the need to unravel an existing allocation later in the planning process.
How Can Developers Reduce the Risk of BNG Changes?
Developers can reduce planning and commercial risk by reviewing the Biodiversity Metric whenever a material change to the development could affect habitat loss, retention, creation or enhancement.
The ecological team should establish whether the change affects post-development biodiversity value and whether the existing BNG strategy still achieves the required outcome.
Where off-site units are involved, developers should also check whether the type and quantity of units required have changed.
Early communication between the developer, ecological consultant, planning team, local planning authority and off-site unit provider can help identify these issues before they affect the construction programme.
If the project is still evolving, obtaining updated off-site quotations as the metric changes can also provide a more accurate picture of the financial implications of different design options.
How Civity Supports Developers When BNG Requirements Change
At Civity, we help developers understand the off-site implications of changes to their Biodiversity Metric.
We do not undertake the developer’s biodiversity metric calculations. Instead, we interpret completed metric outputs supplied by the developer’s ecological team to establish the habitat types and number of off-site biodiversity units required.
If a development layout changes and the ecological team produces an updated metric, we can quickly interpret the revised requirement and provide an updated quotation for suitable off-site units.
We can also consider unit availability, habitat type, trading rules and location when identifying appropriate options. Where suitable units are in short supply or favourable pricing is available, developers may also be able to reserve units or secure them with a deposit before the final requirement is confirmed.
This dynamic approach helps developers understand how changes to their scheme could affect off-site BNG costs without waiting until the Biodiversity Gain Plan is ready for final submission.
Managing Biodiversity Gain Plan Changes Before They Become Delays
An approved Biodiversity Gain Plan cannot simply be edited after approval. Where the approach to achieving the biodiversity gain objective changes before development starts, a new Biodiversity Gain Plan may need to be submitted and approved. Changing the details surrounding existing off-site biodiversity allocations is also not straightforward, particularly once units have been formally allocated and linked to the planning permission. Developers should therefore make sure proposed allocations are suitable before they are finalised.
The key is identifying changes early.
Development layouts, habitat proposals and off-site requirements can evolve throughout the planning process. Reviewing the Biodiversity Metric alongside those changes helps developers understand whether the required biodiversity gain is still being achieved and whether additional off-site units are needed.
At Civity, we work with developers and their ecological teams to interpret changing off-site requirements and provide fast, updated quotations for suitable biodiversity units.
If your project’s metric has changed or you need to understand the cost and availability of revised off-site BNG requirements, speak to Civity about your development biodiversity metric.