Biodiversity Net Gain (BNG) is a requirement that became mandatory through the planning system across England from February 2024. It requires that new developments in the UK create at least a 10% uplift in biodiversity (with some exemptions). Further information can be found across our website.
Biodiversity Net Gain for New Developments
Biodiversity Net Gain (BNG) became a mandatory planning requirement in February 2024 under schedule 7A of the Town and Country Planning Act (1990). This policy was originally introduced in the Environment Act 2021, schedule 14. Some local authorities adopted a BNG policy prior to 2024 as part of their Local Plan, but for most of the country, BNG is a new requirement.
BNG requires that new developments have a positive impact on the environment by creating at least a 10% uplift in biodiversity – this means that development will now result in more or better quality habitat than there was before the development. This must be secured for a minimum of 30 years.
Under the statutory framework for BNG, planning permission will be granted subject to the condition that the required uplift is met. This is a pre-commencement condition, meaning that once planning permission is granted, a Biodiversity Gain Plan must be submitted and approved by the planning authority before commencement of the development. There are some exemptions to the BNG requirements.
Biodiversity net gain is calculated using the Biodiversity Metric Tool. A completed baseline metric should be submitted as part of a Biodiversity Gain Plan. In order to complete a metric, a number of principles and rules need to be met – the first being that the metric is completed by a competent person who has the skills and knowledge to perform specific tasks that feed into the metric calculations. The full details on the principles and rules of BNG can be found on the Department for the Environment and Rural Affairs website.
In the first instance, developers should look to enhance and then restore biodiversity on-site (within the developments redline boundary). If BNG requirements cannot be met completely on-site, a developer can create mitigation off-site on their own land or purchase mitigation units from a registered BNG mitigation provider. If offsite mitigation is not available, a developer can seek approval from the local authority to apply for “statutory credits”.
If a developer is using offsite units or statutory credits, the “Spatial Risk Multiplier” will be applied in the Metric (Figure 1). The Spatial Risk Multiplier accounts for the proximity of mitigation to a development and encourages developers to seek mitigation close to the area impacted by their development. The Spatial Risk Multiplier considers proximity using local planning authority boundaries and National Character Areas for habitat area and hedgerow modules, and waterbody catchment and operational catchments for watercourse modules. The spatial risk category will impact the amount of mitigation required to for the development.
Figure 1 – Spatial Risk Multiplier from the Statutory Biodiversity Metric User Guide (July 2024 verson)
Potential Biodiversity Net Gain Off Site Schemes
There are now operational off-site biodiversity schemes in south Hampshire. The PfSH Solent Mitigation Team is also aware of several potential schemes that may come forward in the future.
The list below provides the contact details of these schemes and will be updated as new sites come forward. The list of schemes is in no way exhaustive of the potentially available mitigation options available to developers, and does not intend to recommend any particular mitigation scheme. The list indicates potential local schemes known to the Partnership for South Hampshire Solent Mitigation Team.
It is the responsibility of the applicant/developer to find suitable and sufficient BNG solutions. Developers should seek their own legal and ecology advice with regard to the suitability of a particular mitigation scheme.
If you have an operational BNG scheme in a PfSH local authority and would like to be added to this list, please contact: EnvironmentalMitigation@fareham.gov.uk
Policy Documents and Resources (Local Policy)
Our partner and member local planning authorities have their own dedicated web pages for Biodiversity Net Gain to advise developers working within their authority:
- Basingstoke and Deane Borough Council
- Chichester District Council
- East Hampshire District Council
- Fareham Borough Council
- Gosport Borough Council
- Havant Borough Council
- Isle of Wight Council
- New Forest District Council
- New Forest National Park Authority
- Portsmouth City Council
- South Downs National Park Authority
- Southampton City Council
- Test Valley Borough Council
- Winchester City Council
- Local Nature Recovery Strategy for Hampshire | Environment | Hampshire County Council
National Policy
The Department for Environment, Food and Rural Affairs (DEFRA) has published a number of resources providing detailed breakdown of the BNG Policy and guidance for local authorities, developers and land managers:
- Biodiversity net gain – GOV.UK (Guidance Collection)
- Biodiversity net gain – GOV.UK (Planning Practise Guidance)
- The Statutory Biodiversity Metric
- Statutory biodiversity metric tools and guides – GOV.UK
- Biodiversity net gain: exempt developments – GOV.UK
- Statutory biodiversity credit prices – GOV.UK
- What you can count towards a development’s biodiversity net gain – GOV.UK
- Register a biodiversity gain site – GOV.UK