Ecologists and environmental scientists call for a small sites levy one year on from mandatory BNG for small sites

The Association of Local Government Ecologists (ALGE), the Institution of Environmental Sciences (the IES), and CIEEM have today sent a letter to the Nature Minister Mary Creagh and the Planning Minister Matthew Pennycook, one year since mandatory BNG came into force for small sites. The letter calls for the introduction of a levy for small sites, stating:

“One year on from the introduction of mandatory Biodiversity Net Gain (BNG) for small sites, we are writing to express our concerns as professional bodies collectively representing over 15,000 ecologists and environmental professionals.

BNG is not currently working for small sites. This is the message from our members and is set out in detail in BNG for Small Sites and BNG in Practice: One Year after Mandatory Implementation.

To meet the BNG requirement, small site developers have to go through a simplified BNG process, which includes requirements for securing a baseline biodiversity metric calculation, and often the purchase of prohibitively expensive off-site biodiversity credits. The majority of biodiversity gains on small sites also have no monitoring requirement and so are at high risk of not being maintained over the required 30 year period.

We support the introduction of a levy for small sites to simplify and accelerate small site development. One option could be to incorporate the levy into the newly announced Nature Restoration Fund system, provided there is robust and transparent accountability for the discharge of this funding on nature gains. This would enable small site developers to follow a simple charging schedule to fulfil their BNG requirements.

The current small sites system is over-complicated and impractical, imposing a disproportionate burden on small developers and further stretching the already limited capacity of ecologists and Local Planning Authorities. Small developments add up; they must support nature recovery and a levy is a more effective and strategic way to achieve this.

We also want to reiterate our strong commitment and support for BNG. We have been highly concerned to hear reports that Defra has been considering its removal. BNG is a world leading piece of legislation that has the potential to be a huge success for development and nature recovery, if action is taken now to address implementation issues. As professional bodies, we are keen to work with the Government to overcome these challenges, and support its vision of a modern planning system that delivers high-quality development together with meaningful nature recovery.”

The IES, ALGE and CIEEM are holding a Small Sites Symposium on 27 May 2025, to further explore the challenges and opportunities faced by mandatory BNG for small sites.