Easing BNG rules: what proposed Government changes mean for SME developers
CrowdProperty examines the Government's review of Biodiversity Net Gain (BNG) rules, which smaller housebuilders in England have found difficult to comply with. The proposals form part of a consultation launched in May 2025 alongside wider housing reforms.
Under the Environment Act 2021, BNG became mandatory for major developments (10 or more homes, or sites above 0.5 hectares) from 12 February 2024, and for small sites of one to nine homes from 2 April 2024. Developers must achieve a 10% net gain in biodiversity, secured for at least 30 years. The Home Builders Federation has pointed to weak national guidance and stretched local authorities as obstacles, with SMEs bearing a disproportionate share of the cost of ecological surveys and metric calculations.
The consultation, led by Deputy Prime Minister Angela Rayner, proposes:
• partial or full exemption, or simpler requirements, for sites of one to nine homes • a less complex biodiversity metric for sites of 10 to 49 homes • allowing planning officers rather than councillors to approve minor applications • excluding 10 to 49-home schemes from the Building Safety Levy • a £100 million loan fund for SME developers
The measures support the target of 1.5 million homes by March 2029. CrowdProperty notes that SMEs delivered around 40% of new homes in the 1980s but a much smaller share today, and that the changes could make small brownfield and infill sites more viable.
Environmental groups are concerned. Wildlife and Countryside Link warns that nearly three-quarters of new developments could lose biodiversity protections, while the Office for Environmental Protection has called for strong governance, monitoring and enforcement.
The article also answers common questions: a Biodiversity Gain Plan prepared by a qualified ecologist is usually needed before final consent; low-value sites still require a 10% gain; off-site delivery through other land, habitat banks or statutory credits is allowed; and gains are secured by Section 106 agreements or conservation covenants.
As the reforms are not yet law, CrowdProperty advises developers to confirm which regime applies, start assessments early, take planning advice and follow updates from DEFRA and local authorities.
