Biodiversity Net Gain (BNG) has become an integral part of the UK planning process. However, it’s crucial to understand that there are certain situations where these requirements may not apply or may be applied differently. In this comprehensive guide, we’ll explore the exemptions to mandatory Biodiversity Net Gain and what this means for different types of developments.
Understanding Biodiversity Net Gain
Before we delve into the exemptions, let’s briefly recap what Biodiversity Net Gain entails. BNG is an approach to development that aims to leave biodiversity in a better state than before. Under the Town and Country Planning Act, most developments are required to deliver a minimum 10% increase in biodiversity value compared to the pre-development biodiversity value of the development site.
When Does Biodiversity Net Gain Not Apply to Development?
While BNG is becoming a standard requirement, there are several types of developments and situations where these regulations may not apply or may be applied differently. Let’s explore these exemptions in detail:
1. Permitted Development Rights
Developments carried out under permitted development rights are generally exempt from BNG requirements. These are types of development that can be performed without needing to apply for planning permission. However, it’s important to note that local planning authorities may still impose conditions related to biodiversity through Article 4 directions.
2. Householder Development
Most householder developments, such as extensions or alterations to a single house, are exempt from BNG requirements. This exemption aims to reduce the burden on individual homeowners undertaking small-scale projects.
3. Self-Build and Custom Build Development
Self-build and custom housebuilding projects are often exempt from mandatory BNG requirements. This exemption is designed to support individuals and communities in building their own homes without the additional complexity of BNG calculations.
4. Brownfield Sites
While not entirely exempt, brownfield sites (previously developed land) may have different BNG considerations. It’s important to note that brownfield sites can sometimes support rare species and priority habitats, so each site needs to be assessed individually. The biodiversity metric takes into account the existing biodiversity value of the site, which can vary significantly for brownfield land.
5. Irreplaceable Habitat
The development of irreplaceable habitats, such as ancient woodland, is subject to different rules. These sites are given special consideration due to their unique ecological value. Key points to understand about irreplaceable habitats and BNG include:
- The 10% net gain requirement does not apply to irreplaceable habitats, as it would be impossible to achieve.
- Developers must agree to a compensation strategy with the planning authority, informed by ecological expertise.
- Irreplaceable habitats must be recorded in the biodiversity metric.
- Planning permission for development that results in the loss of irreplaceable habitat is only granted in exceptional circumstances.
- If there are no impacts, the enhancement of irreplaceable habitats can contribute to a development’s BNG requirement.
6. Urgent Crown Development
Certain urgent developments carried out by or on behalf of the Crown may be exempt from BNG requirements. This exemption is typically limited to developments necessary for national security or emergency response.
7. Existing Planning Permissions
Developments with existing planning permissions granted before the mandatory BNG requirements came into effect may not need to comply with the new BNG rules. However, this can depend on the specific conditions of the planning permission and any subsequent amendments.
8. Developments Below the ‘Threshold’
A development that does not impact a priority habitat and impacts less than:
- 25 square metres (5m by 5m) of on-site habitat
- 5 metres of on-site linear habitats such as hedgerows
9. Nationally Significant Infrastructure Projects (NSIPs)
NSIPs are subject to a different planning regime and have their own biodiversity requirements. While they are not exempt from considering biodiversity, the specific BNG requirements may differ from those applied to other types of development. The BNG requirement for NSIPs in England is due to be implemented in November 2025.
The Role of Local Planning Authorities
It’s important to note that while these exemptions exist at a national level, local planning authorities have significant discretion in how they apply BNG requirements. Some may choose to impose stricter requirements or apply BNG more broadly than the national minimum. This is often reflected in emerging local plans and supplementary planning documents.
Biodiversity Gain Plans and Exemptions
Even for developments that are exempt from mandatory BNG, a biodiversity gain plan may still be beneficial. This plan outlines how development will impact biodiversity and what measures will be taken to mitigate these impacts. While not always required, a biodiversity gain plan can demonstrate a commitment to environmental stewardship and may smooth the planning process.
Off-Site Biodiversity Gains and Statutory Biodiversity Credits
For developments that are not exempt but struggle to achieve biodiversity net gain on-site, off-site biodiversity gains can be an option. This involves creating or enhancing habitats at a different location to compensate for biodiversity losses at the development site.
In cases where neither on-site nor off-site gains are feasible, developers may have the option to buy statutory biodiversity credits as a last resort. These credits, provided by the government, can be used to meet BNG requirements. However, this option is typically only available after exhausting other possibilities in the biodiversity gain hierarchy.
The Future of BNG Exemptions
As the implementation of Biodiversity Net Gain evolves, we may see changes to these exemptions. Government guidance is continually being updated, and local authorities are developing their own policies. It’s crucial for developers and planners to stay informed about these changes.
Navigating the Future: Biodiversity Net Gain and Sustainable Development
While Biodiversity Net Gain is becoming an integral part of the planning process, it’s clear that a one-size-fits-all approach isn’t always appropriate. The exemptions and modifications to BNG requirements reflect the diverse nature of development projects and the need for flexibility in certain situations.
However, even for exempt developments, considering biodiversity can bring significant benefits. It can improve the quality of the development, contribute to local nature conservation efforts, and potentially smooth the planning process.
Understanding when Biodiversity Net Gain does not apply to developments is just one piece of the puzzle. The key is to approach each project with a commitment to sustainable development, balancing the needs of people, wildlife, and the planet.
For more information about Biodiversity Net Gain and how it applies to specific development projects, it’s advisable to consult with ecological experts and local planning authorities. They can provide tailored advice based on the unique characteristics of each development and its location.
