Defra and Natural England have now officially launched version 3.0 of the Biodiversity Metric (Defra Metric 3.0). The latest iteration of the metric has been adapted to respond to feedback and is intended to be more efficient and to help ensure consistency between projects when it is applied.
Biodiversity Net Gain is “an approach to development that leaves biodiversity in a better state than before.”. When applying biodiversity net gain principles, developers are encouraged to bring forward schemes that provide an overall increase in natural habitat and ecological features. The aim of Biodiversity Net Gain is to minimise losses of biodiversity and help to restore ecological networks.
If you are asked to demonstrate a percentage (%) increase in biodiversity value, your ecologist will need to run a metric/calculation and the Defra Metric 3.0 and the small sites metrics are anticipated to become the standard tools for biodiversity net gain calculation as part of the revisions to the Town and Country Planning Act . The Defra Metric 3.0 is supported by updated guidance and condition assessment information, and a new QGIS tool which enables export of data directly into Metric 3.0. A new ‘small sites’  metric has also been released which is a simplified version of Biodiversity Metric 3.0 for small developments.
Measurable Biodiversity Net Gain is already part of the National Planning Policy Framework (NPPF updated July 2021, Para 174 (d) and Para 179(b)) but the NPPF does not specify a number/percentage for the gain. The forthcoming Environment Bill (currently anticipated to receive Royal Assent by end 2021) includes a requirement for all future schemes including the development of land to deliver a mandatory 10 % biodiversity net gain. Whilst it is likely that there will be a substantial transition period prior to this requirement being fully applied by the Act, we recommend that this should be a consideration for site promotion/phased development schemes that will be within the planning system for several years. Although many planning authorities are uncertain about what they can and should be asking for in terms of percentage gain, we are finding that requirements for gain calculations are being made more regularly within pre-application advice. It is also worth noting that some Planning Authorities have already adopted a requirement for measurable net gain in new/emerging Local Plans.
We highly recommend that our clients get to grips with potential biodiversity net gain requirements at an early stage of site identification/design. If you’d like to discuss potential planning requirements and/or implications for Biodiversity Net Gain on site design and capacity then please do get in touch.
 Proposed new section 90A, schedule 7A (4)
 as defined by the Town and Country Planning Act 1990 (as amended).