Biodiversity Net Gain (BNG) aims to ensure that biodiversity (species & habitats) are measurably better off as a result of a development project compared to the pre-development state.
BNG Small Site Metric is required for residential development sites where the number of dwellings is between 1 and 9 on a site of an area 1 hectare or less.
A BNG calculation is required for the initial planning application.
Landscape Planning Discharge drawings are required once planning approval has been achieved.
The UK’s departure from the EU left gaps in the national legislation around environmental protection. The 2021 Environment Bill sought to address this by setting clear targets for air quality, biodiversity, water and waste management, and the reversal of species decline. There is now a mandatory legal requirement to avoid damage to and enhance existing habitats on a site. The aim is to provide nature friendly developments that are good for residents, wider communities, and nature
The legislation to provide a Biodiversity Net Gain (BNG) of 10% is now mandatory for all large developments, 10 or more dwellings) & all small developments, (1 to 9 dwellings)
(with a few exceptions)
Applicable to all full planning applications including change of use (e.g. from house to flats)
A baseline BNG assessment needs to be undertaken at the design stage prior to planning applications
A 'Competent Person' (small sites) or an Ecologist (large sites) will use designated tools to assess each different habitat type to provide a baseline score a habitat contains before development takes place.
The proposed development is required to achieve an uplift of 10% on the baseline score.
The BNG Metric will show the total number of units required and what habitat enhancement or creation will be required as part of the final design
BNG legislation has been introduced following several major reviews in 2010 & 2023 of England’s wildlife showing a significant decline. The COP15 UN Biodiversity Summit in 2022 launched a new global framework for biodiversity, which has been recognised as crucial for our continued health, well-being and economic success.
Planning policy now provides guidance to Local Planning Authorities advising them to:
1. Refuse planning permission if significant harm to biodiversity resulting from a development cannot be avoided, adequately mitigated or, as a last resort, compensated for;
2. Not permit development on land within a Site of Special Scientific Interest or land which will have an adverse effect on the SSSI (with exceptions);
3. Refuse planning permission for development resulting in the loss or deterioration of irreplaceable habitats such as ancient woodland and ancient or veteran trees (with exceptions)
Development whose primary objective is to conserve or enhance biodiversity should be supported; while opportunities to improve biodiversity in and around developments should be integrated as part of their design, especially where this can secure measurable net gains for biodiversity or enhance public access to nature where this appropriate.
Avoiding development on irreplaceable habitats, or negative impacts of on-site existing habitats
Minimising biodiversity loss on a development site by retaining existing habitats and modifying project design and enhancing the retained on-site habitats conditions
Mitigating for on-site loss by increasing biodiversity areas within the site boundaries through new habitat creation to replace non-avoidable ecological damage.
To compensate for any loss of biodiversity through habitat enhancement and creation
off-site by purchasing biodiversity units
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