The Environment Act 2021
The Environment Act 2021 makes a 10% biodiversity net gain mandatory from 2 February 2024. By this date Councils will need to be able to assess and determine planning applications and their associated biodiversity gain plans to check that they are legally compliant. The 10% legislative requirement is mandatory and LPAs do not need to repeat this in policy, but there are good reasons to include BNG policies in Local Plans to support implementation.
Major development includes residential developments with 10 or more dwellings, or a site area exceeding 0.5 hectares. BNG will apply to these developments from 12th February 2024.
BNG for small sites will have an extended transition period and has applied from 2nd April 2024. Small site development includes:
Residential development where the number of dwellings is between 1 and 9, or if unknown, the site area is less than 0.5 hectares.
Commercial development where floor space created is less than 1,000 square metres or the total site area is less than 1 hectare.
BNG for Nationally Significant Infrastructure Projects (NSIPs) will apply from late November 2025.
This is a significant milestone in the delivery of the Environmental Improvement Plan, ensuring new development contributes to the recovery of nature and will be fundamental in helping the country meet its target to halt the decline in species abundance by 2030.
Types of Planning Permission
BNG will apply to all new planning applications for major development from 12th February 2024. Transitional arrangements ensure that BNG only applies to planning applications made on or after 12th February 2024. However, applications made under other routes, such as deemed permissions or Local Development Orders, are not yet subject to mandatory BNG. Developers can still choose voluntary BNG on these projects.
When seeking planning permission, developers must confirm BNG applicability. Approval from the Local Planning Authority (LPA) is a prerequisite before development kicks off.
A locally-specific policy allows a local authority to set out any local priorities and strategies they require developers to take into account in delivering BNG, e.g. locally important habitats, Biodiversity Action Plans, Green Infrastructure strategies and Local Nature Recovery Strategies (LNRS). This will help to target offsite BNG delivery and determine the ‘strategic significance’ score that is part of the Biodiversity Metric.
As such, a locally-specific policy can help to ensure that BNG contributes to wider nature recovery plans in addition to local objectives. It can help ensure that the right habitats are provided in the right places.
Including BNG policies in the Local Plan can link biodiversity to other strategic objectives and the overall place-making strategy for an authority, enabling a more holistic approach. For example, this could be recreation and health, flood risk alleviation, active travel or the more comprehensive climate emergency ambitions of a council.
Set requirements for management and maintenance of habitats provided.
The local authority should also consider setting out how they baseline, measure and monitor BNG delivery as part of Local Plan monitoring.
Some local authorities are considering setting a policy for a BNG target above 10%. This will need to be backed up by appropriate evidence, including that the approach taken will be viable – see below for further information.
You might also want to develop a Supplementary Planning Document to set out details of the approach and set a strategy for off-site delivery.
Local plans and biodiversity
National policy
NPPF Paras 170(d), 174(b) and 175(d)
Natural Environment Planning Practice Guidance
Infrastructure Commissions Design Priciples
National Policy Statements
National Design Guide
Governments 25 year Environment Plan
BS8683