February 2026
The latest research from the University of Sheffield suggests that Biodiversity Net Gain is not a ‘block’ to development receiving planning permission. The analysis, which analysed 235 major housing developments, found that whether planning applications were approved or rejected, the accompanying BNG metrics offered similar percentage levels of mitigation. Researchers also found no significant difference in the area of different habitat types that was destroyed or created between applications that were accepted and rejected. This strongly suggests that applications under the BNG system are not being systematically rejected for reasons connected to biodiversity.
These findings are significant because both the housebuilding industry and the government are keen to present environmental regulation as a ‘block’ to development. Though mandatory BNG is about to celebrate its second birthday, it has had a difficult infancy under Labour. A prolonged review and changes to site thresholds have worried many in the environmental sector, while rumours circulated that the policy in its entirety may face the axe. The ENDS report recently quoted the Managing Director of an environmental consultancy, who captured the uncertainty of the present juncture:
“[Someone well-connected to the government said] ‘well, you know BNG’s for the chop, don’t you?’ It was as if Labour had got into bed with the developers and both were rejoicing in the fact that they could point at nature and say ‘that’s the problem’”[1]
Research for the Planning for Nature Project, funded by the Economic and Social Research Council, seeks to explore the effectiveness of BNG at protecting nature. So far, the project has analysed 235 housing developments, covering 1,134 hectares, across 25 English Local Planning Authorities who were ‘early adopters’ of the policy between 2021 and 2024. We found that approved applications had a 14% median increase in biodiversity units, while those that were rejected had a median increase of 17%, indicating that Local Planning Authorities are not rejecting applications on the grounds of the percentage of mitigation offered. Our analysis also suggests that developers are able to submit adequate metrics - otherwise, we would likely see a difference in the mitigation strategy between applications that are approved and dismissed.
We also examined the proportion of habitat that was created, retained or enhanced, and found that the proportion of each was roughly the same between accepted and rejected applications. 84% of all habitat proposed after development was to be newly created, with 7% retained, and 9% enhanced. Most habitat that was lost was cropland and modified grassland, whilst the largest type of new habitat created was ‘other neutral grassland’. This might suggest that more attention should be paid to habitat retention and enhancement to follow the mitigation hierarchy. However, it may also indicate that the policy is working to dissuade developers from urbanising sites with higher ecological value. This is borne out through interviews that the Planning for Nature team have conducted with housebuilders, who have suggested that BNG is encouraging them to choose less ecologically damaging locations for development.
In a period when nature is being presented as a block to development, it is no surprise that one of the key policies to advance biodiversity, BNG, has come under attack for halting building. Yet the government’s own impact assessment of the Planning and Infrastructure Bill admitted that there is very little evidence that nature is blocking development[2]. When we conducted focus groups last autumn with professionals, local and national government officials and those in the development sector, one key message was that BNG needed time to ‘bed in’ before further changes were made.
[1] Fair, J. (2026) Net gain in numbers: The breakthroughs – and warning signs – as the embattled policy turns two, ENDS Report, 19 February.
[1] Planning and Infrastructure Bill Impact Assessment https://www.gov.uk/government/publications/plannin...
About the Project
The Planning for Nature Project is funded by the Economic and Social Research Council. Further information, including academic papers when they are published, will be made available at our website https://www.planningfornature.org/
Malcolm Tait is Professor of Planning at the University of Sheffield
Kiera Chapman is Research Fellow at the University of Oxford
Rob Davies is Postdoctoral Researcher at the University of Sheffield
Karl Evans is Senior Lecturer in Conservation Biology at the University of Sheffield
Rob Davies, Karl Evans, and Malcolm Tait are supported by ESRC grant ES/Z503459/1. Kiera Chapman is supported by the National Institute for Health and Care Research (NIHR) Oxford Health Biomedical Research Centre [NIHR203316]. The views expressed are those of the authors and not necessarily those of the ESRC, NIHR or the Department of Health and Social Care .
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