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A Step Closer to Biodiversity Net Gain Post-Event Briefing

14 December 2023

Biodiversity net gain (BNG) will soon become a planning norm and Planning Potential hosted a series of timely panel briefing events in Leeds and Harrogate to discuss what this will mean for all of us who work in the built environment sector.

Sam Deegan Associate Director Newcastle

Charlotte Perry Associate Harrogate

Will Rogers Senior Planner Harrogate

Whilst biodiversity net gain (BNG) remains a moveable feast, a huge step forward has been taken following the release of the secondary legislation Planning Practice Guidance (PPG) on 29.11.2023. As always at Planning Potential, we were ahead of the planning curve and hosted a series of BNG seminars attended by a wide range of built environment professionals and revered industry commentators. We were joined by an expert panel with representatives from The Environment Bank, BWB Consulting and Smeeden Foreman, who shared their experiences, lessons and practical tips in how best to address biodiversity net gain responsibilities. The seminars and subsequent debates covered a range of topics and we have captured the salient themes within this briefing.

BNG food chain

Speakers detailed the hierarchy by which BNG will be delivered for new developments, moving from a position of loss of habitat units, to retention of the extent of habitat units, to a new requirement for replacing any lost habitat and subsequent delivery of an additional 10% of habitat units. It is known that some Local Planning Authorities have begun to weave (and implement) this through local policy; however, the legislation will mean that regardless of policy position, 10% delivery will be mandatory with some LPAs setting their own BNG targets and requesting up to 30%, particularly in more southerly regions in England.

Rules are rules

The key focus of discussion was the matter that from January 2024, a mandatory 10% will be required for major developments, which is likely to be attached to planning permissions by way of a pre-commencement condition, aside from a few exemptions. The 10% requirement will only apply to developments submitted after the regulations come into effect. From April 2024, all minor/ small developments will be captured by the legislation.

Policy is evolving

Guidance is emerging from individual LPAs, which will continue to clarify the BNG framework, types of developments and sites which will be subject to the requirements of the new lebgislation, whilst also detailing how the Act will be implemented over a longer-term period.

Frontloading the data

The value of undertaking baseline surveys early in the development process was emphasised given the viability implications of Biodiversity delivery in financial and practical terms. Speakers outlined how calculations and scoring values are uplifted if either being conducted outside of the May – September plant growing season, or via secondary data sources (Google Maps etc.). Such survey methods mean that calculation assessments may result in higher habitat unit scoring attached to sites, which further reiterates the importance of both ongoing maintenance and the preferability of first-hand baseline surveying. Discussions were also held over the submission of BNGrelated information at various stages of the planning process. Acknowledging the value of early consideration from a developer’s side, it was suggested that BNG detail, in the form of a preliminary BNG statement, was likely to be of value when engaging in pre-application discussions. Whilst the preliminary statement would be non-committal, it will give opportunity for project teams to deliberate the suitability of the preferred BNG approach with the Council at an early stage, to enable any alterations to strategy prior to the commitment that follows any subsequent formal planning approval.

A lasting legacy

The obligation for developers to be secured into a 30- year management agreement for BNG delivery was also emphasised as something for clients and developers to be aware of. With the onerous terms being secured by legal mechanism and thus creating liability to secure the vitality of new habitat.

Details need to be ironed out

Questions were posed by delegates on the requirement or attachment of additional management plans to subsequent additional developments, such as extensions, to initial developments which are already subject to a management plan. In the absence of detail within guidance, the understanding of speakers was that management plans would exist separately for each separate phase or instance of development. A degree of understanding over phasing and possible opportunities for future development is therefore also something which clients will need to be mindful of from an early stage, to limit the quantum of management requirements associated to individual development sites. From 2024 small sites and major sites will be assessed using different metrics, with anything beyond the threshold for a small site will be categorised as major – again, the intricacies over site classifications are to be set within subsequent guidance. Nationally Significant Infrastructure Project (NSIP) sites will be subjected to a separate metric, which will not come into play until 2025.

"When planning their BNG strategy, developers must understand which habitats they should retain on-site and which habitats can be most effectively mitigated off-site – without this knowledge, projects might simply be unviable. When sourcing off-site biodiversity units, developers must also know what to look for: Is the land and funding for 30 years secured? Are the required gains achievable? Who is undertaking the reporting and monitoring? Without, developers risk costly planning delays further down the line." quoted by the Environment Bank.

Maintaining a low profile

Speakers also outlined the need for landowners / developers to actively maintain land, to avoid habitat units accruing on unkempt sites, with Open Mosaic, sites being exemplified as high-scoring habitats which can develop if unmanaged on brownfield sites. Open Mosaic Sites, and other Priority Habitats of very high or of high distinctiveness are particularly hard to emulate except from their existing setting, thus making the cost and likelihood of habitat delivery elsewhere likely to pose challenges. Equally, speakers emphasised the need for developers to be considerate of the approach and practicality taken in delivering BNG, with management of fragile habitats likely to pose significant challenges. For example, grassland or wildflower habitat delivery which form part of Public Open Space is unlikely to be sustainable and will be tricky to maintain, due to active usage of the land by communities.

Like for like

The types of habitats surveyed within BNG can be categorised into three separate habitat entities; area-based, hedgerow-based, and water-based, all of which are assessed independently of one another, meaning that habitats for one cannot account for deficiencies in the other when considering approaches to mitigating losses and delivering replacement habitat. This is in accordance with trading rules, which require like-for-like replacement of lost habitat and means that offsetting may be needed in addition to on-site BNG uplift, to account for habitats that cannot be replaced in-situ.

Taking exception to

Applicants are likely to require the adoption of an approach akin to sequential / exception testing, applied in planning practice for flood risk and retail impact assessment, for example, when justifying the means of BNG delivery.

Paying a high price

Statutory credits have been assigned a high-cost price by distributors, due to their intention for being an absolute last resort for BNG delivery. The means of purchase forstatutory credits will require a mandatory purchase of 2no. credits for every 1no. habitat unit required, making it a significantly cost-ineffective method of meeting regulations.

"Accurate calculation of Biodiversity Units (BU) requires LPAs to have access to comprehensive baseline ecological information for both on-site and offsite habitats, as assessed and justified by your advising ecologist. This information is crucial in enabling LPAs to fully comprehend the accuracy of the calculations. Therefore, it is in the best interest of all parties involved to ensure the accuracy and quality of information is prioritized from the beginning. Early engagement of an ecologist will aim to better inform the design of a scheme as it progresses and ensure delays are minimised throughout the planning process, this will also enable the completion of timeconstrained surveys for protected species in alignment with BNG requirements." said Maria Gill, Smeeden Foreman.

Held to account

At present, there is no regulatory body in place to oversee the issuing and management of bought habitat units; however, it is expected that such a mediator will be introduced by DEFRA by the time BNG becomes mandatory. Essentially, this should stop land being inappropriately sold as habitat units, and also will prevent inadequate management of habitat by those provisioning such services – offering reassurance to applicants and developers that offsite delivery on third party or banked land will be processed through appropriate transaction mechanisms and will result in the fair placement of liability for management of BNG sites. 

Reliance on conditions

We know that the 10% requirement is to be enclosed as a pre-commencement condition on planning consents, which is to be discharged by submission of the finalised BNG Plan and template and agreed with relevant Council Officers. Similarly, the agreement of the 30-year management plan would also be secured by way of planning condition. Section 106 agreements will be the means to secure onsite delivery, separate to the statutory precommencement condition, meaning that it is likely that some LPAs are likely to require separate s.106s for delivery on sites whereby developments affect the red line boundary extent.

"Whilst, as Ecological Consultants, many of us are well-versed in the use of the Biodiversity Metric and its application on development sites, the secondary legislation provides some much needed clarity as to how this will fit into the wider planning system. There will undoubtedly be a period of adjustment in 2024, as Local Authorities in particular deal with the changes. However, I expect that by the end of 2024 at the latest, BNG will be regarded within the planning system in the same way as many other statutory requirements such as Affordable Housing, Public Open Space and Infrastructure funding provisions." said Sarah Stone from BWB.

Show your colours

To combat complexities associated to the above, the use of blue line boundaries, which demonstrate the ownership extent of applicants around development sites, will become a more common approach to demonstrating off-site delivery and can be incorporated into section 106 agreements and other legal covenants. Blue lines should therefore be considered in baseline surveys, in addition to the natural considerations of red line boundaries and will be used to support the subsequent discharging of conditions, due to their capture within section 106 agreements or other legal covenants.