The current version of Scotland’s National Planning Framework (NPF4) sought to reshape the planning system to allow climate change and nature recovery to be considered in all plans and decisions, supporting development that benefits biodiversity. Policy 3 sets out that all national or major developments, or those subject to an Environmental Impact Assessment (EIA), will only be supported where it can be demonstrated that significant biodiversity enhancements are provided in the proposal.
The absence of an established Scottish quantitative approach to assessment of biodiversity value has resulted in the use of an array of methods to calculate biodiversity enhancement (also referred to here as Biodiversity Net Gain (BNG)), including variations of the English statutory biodiversity metric. This has created discrepancies in BNG calculations, causing confusion and inconsistency within the planning system.
To address this, NatureScot announced a public consultation on the introduction of a Scottish Planning Biodiversity Metric (SPBM), starting on 31st August 2026 and ending on 30th November 2026. The SPBM draws upon the English statutory biodiversity metric, adapting it to better complement Scottish Policy and the diverse range of environments and landscapes it encompasses, and seeks to provide a consistent and transparent approach to calculating changes in biodiversity at a project level, in terms of habitat loss, compensation and enhancement in the Scottish system.
Key differences between the Scottish and English approaches
There are a number of differences between the two approaches to measuring and compensating for impacts to biodiversity, and we have highlighted some of these below.
Policy-Led vs Legislative
Whereas the English Government brought in a legal requirement for certain developments to deliver at least 10% BNG, the Scottish planning system has adopted a policy-led approach requiring certain developments to deliver “significant biodiversity enhancements” without requiring a specific numerical uplift. This allows for a more qualitative consideration of biodiversity and the SBPM includes a sheet which allows a user to add biodiversity measures, such as homes for bees, bats, bugs etc. Crucially, the SBPM doesn’t assign a value to these measures, but it does highlight a more holistic approach to delivering BNG, rather than “simply becoming ‘a numbers game’” as the User Guide suggests.
Spatial Risk
Both the English and proposed Scottish systems have introduced a mitigation hierarchy for biodiversity. These are broadly similar as they seek to:
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Avoid impact in the first place;
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Minimise impact;
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Restore or enhance on-site habitats; and
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Offset impacts through compensatory provision with a preference for on-site delivery over off-site delivery.
To further reinforce on-site delivery, both the proposed Scottish and English approaches apply a spatial risk multiplier.
In Scotland, the multiplier effect results in 1 Biodiversity Unit (BU) off-site being worth 0.9 BUs. The same multiplier is applied regardless of the distance from the site.
In England, the negative effect of the risk multiplier increase with distance from the development site. There is no negative impact for off-site delivery within the same Local Planning Authority (LPA) area or National Character Area (NCA). Within a neighbouring LPA or NCA, 1 BU becomes worth 0.75 BUs as compensation value. Beyond the neighbouring LPA or NCA, 1 BU is only worth 0.5 BUs as offsite compensation.
Lessons learnt from the English system
Mandatory BNG has been in force in England since February 2024. Whilst there has undoubtably been a bedding-in period for the industry as understanding and training progresses, the challenges of implementing the new system are easing.
When to consider BNG?
There is no flexibility in England to factor in viability when meeting the BNG Requirement; delivering 10% BNG is a legislative requirement and cannot be reduced in any way.
It has become increasingly important to consider biodiversity at the outset, both in terms of site selection and the design process. The extent of high value habitats on site could significantly impact on developable area, particularly if the cost of mitigation, either on-site or off-site, is prohibitive.
Development of a wider BNG ecosystem
In the early period, the wider system (comprising the private market, Government guidance etc.) which now supports the implementation of mandatory BNG was in its infancy. In many cases, this caused significant delays to the planning process.
Now however, there is a functioning market for the sale of offsite BUs which facilitate developments that cannot deliver 10% BNG on-site. Many LPAs have published guidance and template legal agreements, and the Government are working to improve exemptions for England, streamline the Metric, increase flexibility for minor developments, and target specific issues such as open mosaic habitat on brownfield sites.
What opportunities does the Scottish BNG Metric present?
The main driver for, and key benefit of, the SBPM is to bring consistency to the measurement of biodiversity value in Scotland to support the delivery of NPF4, with the hope that it will improve outcomes for biodiversity improvements in Scotland.
The introduction of the SBPM also presents an opportunity for landowners, local authorities, and developers within Scotland to create their own habitat banks from which BUs can be traded. Unlike England, the Scottish spatial risk multiplier is not distance-dependent. It is logical therefore to assume the catchment within which a Scottish BU bank could serve would be wider as customers would not incur additional negative penalties.
Questions to be answered
How will BNG be secured on a planning permission?
Through a legislative approach to delivering BNG, the English system imposes a standard planning condition to all relevant planning permissions securing mandatory BNG. With the policy-led approach in Scotland, the consultation does not consider how BNG could be secured. Whilst the SBPM will reduce inconsistency in one part of the planning system, inconsistencies could remain around securing the delivery of biodiversity enhancements. Clarification on this would likely be welcomed.
Will a Biodiversity Gain Site Register be created?
A Biodiversity Gain Site Register, managed by Natural England, records all Biodiversity Gain sites where offsite biodiversity enhancements are planned or delivered in England. The Register, use of which is mandatory, is a key part of the BNG system in England and supports the functioning of the private market. The Scottish consultation does not indicate whether it is intended for a similar a Register to be created to enable a similar “market” for BUs in Scotland. This risks delays to the planning system if off-site BUs are not available to mitigate impacts of new developments.
How can Lichfields assist?
Lichfields are well versed in the implementation of mandatory BNG in England and are well placed to apply this knowledge to assist clients in drafting representations to the ongoing Scottish consultation.
