Biodiversity Net Gain, commonly known as BNG, is now a central part of the planning system in England. Introduced under the Environment Act 2021, BNG requires most new developments to leave biodiversity in a measurably better state than before development began. For developers, landowners and planning consultants, BNG is no longer an emerging policy. It is now a material planning requirement that directly affects land acquisition, site viability, programme timelines and plann