Improving the implementation of Biodiversity Net Gain for minor, medium and brownfield development

Biodiversity Net Gain (BNG) is an approach to development which aims to leave the natural environment in a measurably better state than beforehand. The Environment Act 2021 introduced a mandatory BNG requirement in England for most new developments under the Town and Country Planning Act 1990, requiring them to deliver a 10% increase in biodiversity. Following a two-year transition period, BNG has been mandatory for most major developments from 12th February 2024, and for minor development (small sites) from 2nd April 2024.  

The government is committed to delivering sustained economic growth as set out in our Plan for Change and building 1.5 million homes by the end of this Parliament. At the same time, we are committed to halting and reversing the decline of nature. BNG provides a clear framework to ensure development leaves biodiversity in a measurably better state, delivering health and wellbeing benefits to local communities, providing wider benefits for climate change adaptation and mitigation and contributing to our legally binding Environment Act 2021 targets for biodiversity.

The government has been working closely with stakeholders to gather feedback and evidence on how BNG is being implemented. Early information suggests BNG implementation has been broadly successful for larger developments, with a greater number of developers seeking ecological advice earlier in the process and designing their site layouts to avoid impact to biodiversity and seek to deliver more habitat onsite.  

For those who are unable to meet all of their BNG onsite, an off-site market is also rapidly developing with over 2500ha of habitat created or enhanced currently listed on the national register, and many more sites preparing for registration, thereby helping to increase private investment into nature recovery. There have been over 265 off-site allocations made so far to developments, enabling homes to be delivered when onsite BNG is not feasible. We have also seen innovative tech start-ups form to aid off-site market development and help smaller developers engage with the market. These tech businesses also offer services to local planning authorities that help manage their BNG responsibilities.

However, although the consensus is that BNG is working well as a whole, there is emerging evidence that some smaller developments and specific types of development are finding the operation of BNG is not as effective as could be. Minor and medium development has an important role to play in meeting the government’s housing targets and we want to go further in shaping the future of BNG to ensure the framework is simple and proportionate for SME developers whilst delivering on its potential for nature. This will be taken forward alongside broader work to reduce the burden on SME developers which the ‘reforming sites thresholds’ working paper sets out.