Over 140 signatories from across the construction and built environment sector have called for the government to retain Biodiversity Net Gain requirements for small sites and adopt a more proportionate approach to reform.
The Green Construction Board (GCB) and UK Green Building Council (UKGBC) have coordinated an open letter, which has been backed by developers, contractors, consultants, ecologists, engineers, financiers, planners, academics, land managers, membership and professional bodies.
Signatories include Professor Sir John Lawton CBE FRS, author of Making Space for Nature, and Sir Partha Dasgupta, author of The Economics of Biodiversity: The Dasgupta Review, businesses and professional bodies from across different sectors, including the Association for Consultancy and Engineering and Environmental Industries Commission, Aldersgate Group, Wates Group, Knepp Estate and Triodos Bank.
The letter stresses the recent findings of the Environmental Audit Committee, stating that nature is not a blocker to housing growth, and says that well-designed nature policy can instead support delivery, improve quality of life and enhance long-term property asset value.
In May, the government set out plans to simplify rules for SMEs, easing BNG requirements for “minor” developments of up to nine homes, and introducing a new “medium site” category, which would also benefit from simplified BNG rules.
The letter recommends alternatives to the proposed blanket exemption for small sites, such as a 0.1-hectare area-based exemption threshold, rather than the proposed 1-hectare threshold. It says this would offer a more balanced and workable solution that would simplify requirements for over 50,000 of the smallest developments each year, while continuing to support nature recovery, long-term asset value and the health and well-being benefits that access to green space provides for communities.
The signatories warn that a blanket exemption for small sites would risk undermining nature recovery at scale, penalising businesses that have already invested in delivering BNG, and weaken confidence in the emerging nature markets that are beginning to unlock private investment in habitat restoration and recovery.
Dr Martina Girvan, chair of the Green Construction Board’s Biodiversity and Environmental Net Gain Group, said: “This letter demonstrates the strength of business and expert support for Biodiversity Net Gain and for nature-positive development. Small sites are often where the loss of green space is felt most acutely, particularly in urban areas. Even modest areas of green infrastructure can deliver significant social and environmental benefits, from cooling and flood mitigation to improved health and wellbeing. Removing BNG from these sites risks embedding poorer outcomes for communities and missed opportunities to enhance the quality of places where people; risking a negative long-term legacy that neither residents nor businesses want.”
David Pinder, chair of the Green Construction Board, added: “The industry is clear that Biodiversity Net Gain and nature protections are not anti-growth. Proportionate and practical solutions exist. A 0.1-hectare exemption would reduce complexity for the smallest schemes without undermining nature recovery, investor confidence or the businesses that have committed to doing the right thing. A blanket exemption would be a backwards step for nature, markets and long-term value.”
The letter reiterates that BNG is a central pillar of the Green Construction Board’s Biodiversity Roadmap for the sector, published by the Construction Leadership Council, and a key mechanism for delivering the UK’s legally binding environmental targets under the Environment Act, as well as wider international commitments on nature and biodiversity. The signatories caution that weakening BNG through wide-ranging exemptions would contradict these commitments and undermine the UK’s leadership in mobilising private finance for nature recovery.
With businesses, investors and local authorities already preparing to deliver BNG at scale, the coalition is calling for policy certainty and proportionate refinement, rather than wholesale rollback. They urge government to work with industry to streamline delivery on small sites, while maintaining the integrity of a policy that supports growth, resilience and high-quality, nature-positive places.
