Nicky Brock of Carter Jonas argues that a small procedural change to biodiversity net gain approvals could unlock faster delivery without compromising environmental outcomes.
There is no question that the planning system requires more speed and more certainty – and much of what the Government has put in place in the last year is on track to achieve this.
But while, on a macro level, planning reform is heading in the right direction, for those of us dealing with planning applications day-in, day-out, it’s the small procedural frictions that cause the biggest frustrations.
The requirement for local planning authorities to approve pre-commencement conditions for biodiversity net gain (BNG) is perhaps one of the most important to unpick.
BNG is doing exactly what it was designed to do: placing nature recovery at the heart of (almost) all development. The problem is how it is being sequenced. The current approach requires an extra post-consent approval step that can cause material delays.
If government wants a simple win that supports both nature recovery and delivery, it should focus on streamlining the pre-commencement mechanics of BNG.
How the problem manifests itself
I recently gained planning consent for a mid-sized greenfield housing scheme in Oxfordshire. Planning consent was issued within three months. The BNG solution, which was offsite, was straightforward: the units were purchased and the certificate submitted, yet eight weeks after consent we were still waiting for the BNG approval outcome. The knock-on effect is delays to housing delivery, including affordable housing, and to wider economic activity.
Where a scheme has already secured offsite units, the local authority is not being asked to weigh up competing habitat proposals or negotiate a bespoke ecological strategy; the developer is presenting a package that is designed to be compliant. Yet the statutory framework still requires a formal approval period before the condition is discharged and commencement can take place lawfully.
This is not a theoretical scenario. Historically, I would work hard to avoid pre-commencement conditions and potential delays by submitting all necessary documentation at application stage so that technically, a development could start the day after consent. BNG is the outlier – and this sequencing is particularly hard to justify where the offsite gain is already verified and could be paid for.
What makes BNG different
We are used to pre-commencement conditions. They are a routine feature of planning permissions, and they exist for good reasons. Contamination, archaeology, drainage strategies, construction management and ecological mitigation can all be controlled through conditions that must be discharged before works start.
The difference is that these conditions can usually be addressed either by providing the supporting information alongside the planning application or by discharging them swiftly following consent.
In the case of BNG, however, legislation requires a specific document, the Biodiversity Gain Plan, to be submitted and approved after permission is granted and before commencement, as a requirement of the statutory ‘general condition’ introduced through the Environment Act changes to the Town and Country Planning Act. There is no flexibility for LPAs to alter this process because the mechanics are embedded in the regulatory framework for BNG, the Biodiversity Gain (Town and Country Planning) (England) Regulations 2024.
What’s more, the Regulations (Paragraph 031) are explicit that the biodiversity gain plan must be submitted no earlier than the day after planning permission has been granted.
The broader impacts
Not only does this issue cause delays to specific schemes, it also exacerbates pressures on local authority planning departments precisely when capacity is most stretched. BNG submissions are arriving at scale, while many authorities are still bedding in a new regime, and dealing with skills gaps that often include ecology and biodiversity.
It also produces inconsistency. Some authorities require a full biodiversity gain plan to be submitted as part of the application and then a post consent pre-commencement condition discharge, thus ‘double counting,’ while others are willing to accept an outline approach with details to be submitted post-consent. For developers operating across multiple authorities, that variability makes programmes harder to manage and increases risk.
Another important point is that BNG can become uniquely rigid in a system where other forms of planning gain are often subject to negotiation and viability testing. We may debate the right balance, but it is hard to defend a process where some obligations are revisited when viability is tight, yet BNG has so little flexibility, even when compliance is not in doubt.
The need for a review
Defra has now published its response document to the consultation, entitled ‘Improving the implementation of BNG for minor, medium and brownfield development.’ The proposed changes focus on proportionality, particularly exemptions, the small sites metric, and access to the offsite market.
All of that is useful, but it fails to address the key question of how the requirement for BNG can be realised without significantly delaying the planning process.
What a workable reform could look like
Streamlining does not have to mean weakening. A better approach is to align BNG with how we already manage other technical matters: clear principles at decision stage, with proportionate detail secured through staged approval and enforcement.
My recommendation is, where appropriate, to allow the required biodiversity gain plan to be approved prior to determination.
Crucially, this is a practical solution for projects; one that should not require primary legislation. The Environment Act sets the principle, but much of the operation is controlled through regulations and guidance. Government could amend the Biodiversity Gain (Town and Country Planning) (England) Regulations 2024 and update Planning Practice Guidance to create flexibility around timing while maintaining enforceable outcomes.
Conclusion
Achieving the goal of Biodiversity Net Gain should remain non-negotiable in principle, but at the same time it should not be uniquely immovable in practice. If we want planning permissions
to translate into homes and infrastructure quickly, streamlining BNG’s pre-commencement mechanics is one of the most straightforward changes that could be made – and one that could improve both delivery and confidence in the system.
Nicky Brock is partner at Carter Jonas