The statutory framework for biodiversity net gain includes specific modifications for planning permissions (including outline permissions) that have the effect of permitting development which proceed in phases (termed ‘phased development’ in this guidance). This reflects that phased development can occur over a long period of time where full details of all phases may not be known at the time of planning permission. For these permissions, the standard approach may not be possible. The arrangements for approving the biodiversity gain plan for phase development need to follow a different approach.
These modifications for phased development apply to :
(a) a grant of outline planning permission where the reservation of matters for subsequent approval has the effect of requiring or permitting development to proceed in phases; or
(b) a grant of any kind of planning permission, where the grant is subject to conditions which requires development to proceed in phases
An example of a phased development would be a large scale urban extension for residential or commercial development where an outline planning permission has been granted and the permission identifies clear phases for development where subsequent reserve matter approvals would grant content for the detailed design of a phase.
Not all outline planning permissions will meet these requirements. For instance, an outline permission for a small-scale residential development where appearance and landscaping were the only reserved matters for later determination is unlikely to do so, and it would be subject to the standard provisions for biodiversity net gain.
When granting planning permission for a development which is to be phased, the decision-maker will indicate on the written decision notice whether the development is to proceed in phases. The decision notice will also include information relating to the approval of the biodiversity gain condition and that the phase development modification would apply. Applicants may want to confirm with the planning authority that the development is phased prior to submitting an Overall Biodiversity Gain Plan.
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How is biodiversity net gain approached for phased development?
A phased development must meet the biodiversity gain objective of at least 10% net gain (unless it is exempt or subject to transitional arrangements). However, phased development is subject to a different approach for meeting the biodiversity gain condition.
The Biodiversity Gain (Town and Country Planning) (Modifications and Amendments) (England) Regulations 2024 modifies the general biodiversity condition for planning permissions which are phased development. Instead of the standard approach for the Biodiversity Gain Plan:
an Overall Biodiversity Gain Plan must be submitted to and approved by the planning authority before any development can begin; and
a Phase Biodiversity Gain Plan for each phase must be submitted to and approved by the planning authority before the development of that phase can begin.
In recognition that phased development can often be implemented over a long period of time, the purpose of the Overall Biodiversity Gain Plan is to confirm that there is a clear upfront framework for how the biodiversity gain objective of at least a 10% gain is expected to be met across the entire development. Each Phase Biodiversity Gain Plan will subsequently set out a phase’s contribution to biodiversity net gain and confirm progress towards the overall biodiversity gain objective for the development once clear proposals for each phase have been developed. It may be appropriate that where an outline planning permission has been granted for a phased development, that subsequent Phase Biodiversity Gain Plans would be prepared alongside the application for reserved matter approvals for those phases.
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How should applicants approach biodiversity net gain for phased development when preparing proposals?
As a phased development is likely to be a substantive development, so applicants seeking planning permission for phased development are encouraged to engage with the local planning authority as part of their wider pre-application engagement about the development so the strategy for delivering the biodiversity net gain (including the balance between onsite and off-site gains) is known and factored into the preparation of the development’s masterplan and phasing strategy. In some cases, if the development has been allocated in a local plan, there may be a strategic allocation policy which sets out the expectations for the delivery of biodiversity net gain for the development.
When a planning application is submitted for phased development, applicants are strongly encouraged to provide sufficient information to enable the local planning authority to consider how the objective of at least 10% biodiversity gain is expected to be achieved for the development. Such information is likely to include:
the proposed balance between onsite gains, off-site gains and possible use of biodiversity credits;
proposals for any significant onsite enhancements and how the implementation will be phased; and
potential requirements for s106 agreements for both onsite and off-site gains.
Applicants and local planning authorities should discuss the expected biodiversity net gain information requirements for the planning application for a phased development as part of their pre-application engagement.
Applicants may want to submit a draft Overall Biodiversity Gain Plan as part of their planning application although further information about, for instance, proposals for significant onsite enhancements and the approach to offsite gains may be required so these gains can be secured through planning conditions or section 106 planning obligations should planning permission be granted.
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Does the biodiversity net gain objective of at least 10% gain apply to each phase?
The biodiversity gain objective of at least 10% net gain applies to the overall development (not each phase). The contribution of each phase to achieving net gain may vary, providing a net gain of at least 10% is achieved for the overall development at the time of its completion.
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How is the pre-development biodiversity value calculated for phased development?
The pre-development biodiversity value of the onsite habitat for a planning permission for phased development is calculated on the same basis as other permissions. This biodiversity value is for the onsite habitat of the entire development (not each phase). It will not change regardless of the approach to phasing. Later changes to the condition of onsite habitat on a phase prior to its commencement are not relevant to the calculation of the pre-development biodiversity value for phase development.
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What is contained in an Overall Biodiversity Gain Plan?
The content of an Overall Biodiversity Gain Plan is different in several ways from a standard Biodiversity Gain Plan reflecting that there is unlikely to be detailed proposals agreed at the outset.
The Overall Biodiversity Gain Plan for a phased development (which is not related to a section 73 permission) must include the following matters:
information about the steps taken or to be taken to minimise the adverse effect of the development on the biodiversity of the onsite habitat and any other habitat;
the pre-development biodiversity value of the entire onsite habitat;
any registered offsite biodiversity gain allocated or proposed to be allocated to the entire development and the biodiversity value of that gain in relation to the development;
any biodiversity credits purchased or proposed to be purchased for the entire development; and
the post-development biodiversity value of the onsite habitat for the entire development and each phase of development*
*The post-development biodiversity value of the onsite habitat for the entire development and each phase is a projection of the biodiversity value at the completion of the entire development (not after the completion of each phase). Where firm proposals for development and habitat enhancement on each phase have yet to be finalised, assumptions about the likely development and habitat enhancements should be used to determine this post-development value. This value will set the expectations about the biodiversity value of onsite habitats, and the final value will need to be set out in later Phase Biodiversity Gain Plans.
The Overall Biodiversity Gain Plan must also include the following further information:
name and address of the person completing the plan, and (if different) the person submitting the plan;
a description of the development and planning permission reference number (to which the plan relates);
pre-development plans showing the location of existing onsite habitat and drawn to an identified scale and showing the direction of North;
the relevant date, for calculating the pre-development biodiversity value for the development, and if proposing an earlier date, the reasons for using this earlier date;
completed biodiversity metric calculation tool(s) stating the publication date of the biodiversity metric used and showing the calculation of the pre-development and post-development biodiversity values;
arrangements for the maintenance and monitoring of significant onsite habitat enhancements;
a description of how the Biodiversity Gain Hierarchy will be followed and where to the extent one or more actions in that hierarchy are not followed, the reasons if not (except for irreplaceable habitats);
a description of any irreplaceable habitat on the land to which the plan relates which exist on the relevant date, and any part of the development for which planning permission is granted where the onsite habitat of that part is irreplaceable habitat arrangements for compensation for any impact the development has on the biodiversity of the irreplaceable habitat; and
a statement whether habitat degradation has taken place, and if it has:
a statement to this effect,
the date immediately before the degradation activity,
the completed biodiversity tool showing the calculation of the biodiversity value of the onsite habitat on that date, and
any available supporting evidence for the value.
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What is considered when determining an Overall Biodiversity Gain Plan?
The planning authority must only approve the Overall Biodiversity Gain Plan for a phased development (if it is not a section 73 permission) if they are satisfied:
that the pre-development biodiversity value of the entire development’s onsite habitat specified in the Plan is correct;
that the biodiversity gain objective of at least 10% net gain will be met taking account of the post-development biodiversity value for the onsite habitat for the entire development and each phase, the allocation and proposed allocation of registered offsite biodiversity gain, and the purchase and proposed purchase of biodiversity credits;
any registered offsite gain specified as allocated to the entire development have so been allocated;
any biodiversity credits specified as purchased for the entire development have so been purchased; and
If the development includes onsite irreplaceable habitats, the adverse effect of the development on the irreplaceable habitat’s biodiversity is minimised and appropriate arrangements have been made compensation any impact.
In deciding whether to approve the Plan, they must also take account of the Biodiversity Gain Hierarchy (except in relation to irreplaceable habitats).
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What is contained in a Phase Biodiversity Gain Plan?
The content of a Phase Biodiversity Gain Plan is intended to be more limited in scope than an Overall Biodiversity Gain Plan, instead of detailing the overall strategy (like the Overall Plan), the Phase plan focusses on a phase’s contribution to biodiversity net gain and confirming progress towards the overall biodiversity gain objective for the entire development. It must include the following matters:
the post-development biodiversity value of the onsite habitat for the phase of the development (which is the subject of the Plan);
the post-development biodiversity value of the onsite habitat for each other phase of development (whether begun or otherwise);
any registered offsite biodiversity gain allocated to the entire development and the biodiversity value of that gain for the development prior to submission of the phase plan;
any registered offsite biodiversity gain which is proposed to be allocated to the entire development and the biodiversity value of that gain in relation to the development;
any biodiversity credits purchased for the entire development prior to submission of the phase plan; and
any biodiversity credits proposed to be purchased for the entire development.
The Phase Biodiversity Gain Plan must also include the following further information:
name and address of the person completing, and (if different) the person submitting the plan;
description of the development and planning permission reference number (which the person submitting the plan considers is relevant to the phase of development);
post-development plans for the phase of development showing the location of existing onsite habitat (including any irreplaceable habitats) and drawn to an identified scale and showing the direction of North;
a completed biodiversity metric calculation tool(s) stating the publication date of the biodiversity metric used and showing the calculation of the pre-development and post-development biodiversity values;
information about the steps taken or to be taken to minimise the adverse effect of the phase of development on the biodiversity of the onsite habitat;
arrangements for the maintenance and monitoring of significant onsite habitat enhancements;
a description of how the Biodiversity Gain Hierarchy will be followed and where to the extent any actions in that hierarchy are not followed, the reasons if not (except for irreplaceable habitats); and
a description of any irreplaceable habitat on the land to which the plan relates which exist on the relevant date, and any part of the development for which planning permission is granted where the onsite habitat of that part is irreplaceable habitat arrangements for compensation for any impact the development has on the biodiversity of the irreplaceable habitat.
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What is considered when determining a Phase Biodiversity Gain Plan?
The planning authority must only approve the Phase Biodiversity Gain Plan if they are satisfied:
that post development biodiversity value of the onsite habitat for the phase (which is the subject of the Phase Plan) is at least the value specified in the Phase Plan;
the post development value of the onsite habitat for any other phase which has begun is at least the value of specified in the Phase Plan most recently approved for that phase (unless there has been a section 73 permission which has affected the value in that earlier Phase Plan);
any registered offsite biodiversity gain allocated and biodiversity credits purchased for the development are at least the value specified in this Phase Plan;
the biodiversity gain objective of at least 10% gain will be met for the entire development, taking into account the post development of the onsite habitat of the entire development and each phase (whether begun or not), the biodiversity value of any registered off-site gain allocated or proposed to be allocated to the entire development, and any biodiversity credits purchased or proposed to be purchased for the entire development; and
If the phase (which is the subject to the Phase Plan) includes onsite irreplaceable habitats, the adverse effect of the development on the irreplaceable habitat’s biodiversity is minimised and appropriate arrangements have been made to compensate any impact, having regard to he Overall Biodiversity Gain Plan for the entire development.
In deciding whether to approve the Plan, they must also take account of the Biodiversity Gain Hierarchy (except in relation to irreplaceable habitats).
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