By Laura Potts, MRTPI, Planning Consultant
As awareness of climate change and the importance of environmental protection grows, the role of biodiversity in planning applications has become increasingly central. Biodiversity now needs to be an integral part of the planning process and in 2024, Biodiversity Net Gain was introduced and this has raised the bar further, demanding real measurable improvements to the natural environment.
Biodiversity has been back in the news in the last few weeks as the government is consulting on new plans, which are out for consultation, whereby smaller developments (which make up 70% of all housing projects in England) could potentially be exempt from meeting Biodiversity Net Gain requirements. This is driven by the Government’s strategy to speed up housebuilding to meet their ambitious housing targets of 1.5 million new homes by the end of this Parliament. However, the mooted rollback of Biodiversity Net Gain has attracted strong condemnation by wildlife trusts and other environmental protection groups.
At CAD Planning, we are keeping a keen eye on these developments and will watch out for the outcome of this consultation, so we can provide best current advice to our clients.
The Legal Landscape
Planning for biodiversity in the UK is shaped by a robust statutory framework. Key pieces of legislation and policy include:
• The Environment Act 2021: This landmark Act places new obligations on local planning authorities, most notably the mandatory requirement for Biodiversity Net Gain (BNG). Developers are now required to demonstrate a measurable improvement in biodiversity, typically a minimum of 10% net gain, on or off site.
• The National Planning Policy Framework (NPPF): The NPPF sets out the Government’s planning policies for England. It emphasises the need to minimise impacts on biodiversity, provide net gains where possible, and promote the protection, enhancement, and creation of priority habitats and ecological networks.
• Wildlife and Countryside Act 1981: This Act offers protection to certain species and habitats, and underpins the designation of Sites of Special Scientific Interest (SSSIs).
• Habitats Regulations 2017: These regulations ensure that development does not adversely affect internationally important wildlife sites, such as Special Areas of Conservation (SACs) and Special Protection Areas (SPAs).
• Local Nature Recovery Strategies (LNRS): Introduced through the Environment Act, LNRS provide a framework for identifying, mapping, and recovering important habitats and species at a local level.
• Phased implementation: Since February 2024, BNG has applied to major developments; from April 2024, smaller sites were brought in, subject to exemptions.
• The government carried out a consultation earlier this year in respect of exempting minor and medium sites from BNG, and separately consulting on bringing nationally significant infrastructure projects (NSIPs) into the regime.
Biodiversity Net Gain
Since April 2024, developers in England must show Biodiversity Net Gain from projects and this must be secured and monitored over a 30 year periodthrough legal agreements.Biodiversity Net Gain (BNG) requires developers to quantify the biodiversity value of a site pre- and post-development using the DEFRA Metric, which considers habitat type, size, condition, and distinctiveness.
Cornwall: Local Application
In Cornwall, planning applications must show compliance with BNG.
Some minor projects in Cornwall may qualify for exemption if:
• The development affects less than 25m² of vegetated habitat or fewer than 5 metres of hedgerow.
• There’s no impact on priority habitats, which are rare or ecologically important in Cornwall.
• The build is a self-build project, where the applicant is also the future occupant—though Cornwall Council may apply conditions.
Challenges and Opportunities
While the benefits of integrating biodiversity into planning are clear, it is not without challenges. Common hurdles include:
• Knowledge Gaps: Some applicants underestimate the complexity of biodiversity assessments or lack access to experienced ecological consultants.
• Time Constraints: Ecological surveys are often seasonally limited—certain species or habitats can only be accurately surveyed at specific times of the year.
• Space Limitations: In urban or high-density developments, physical space for meaningful biodiversity enhancements can be scarce.
• Costs: Biodiversity enhancements may entail additional costs, both during construction and for ongoing management.
• Capacity gaps in local planning authorities: many councils lack the resources or in-house expertise to scrutinise BNG assessments fully.
The Wider Planning Reform Context
The government’s Planning & Infrastructure Bill (2025) proposes significant reforms to planning, environmental assessment, and infrastructure delivery. These changes could interact with BNG, for example by altering how ecological obligations are funded or monitored, and how housing targets are balanced against environmental protection.
Conclusion
In summary, biodiversity is now an essential consideration in planning applications throughout the UK and will remain so. Legal requirements and policy drivers mean it can no longer be sidelined and whatever the outcome from the current consultation, it is a subject where housebuilders and project developers will need to comply over the long term.
Decisions on exemptions and NSIP inclusion are expected later in 2025. Until then, BNG obligations remain in force, and developers should plan on the basis that biodiversity requirements are not going away.
At CAD Planning, we are staying abreast of this fast-changing topic as well as all other issues affecting planning applications for our clients.
Get in touch to find out how we could help you with your project by emailing info@cad-planning.co.uk