Following the enactment last November of the Environment Act, a mandatory 10% biodiversity net gain (BNG) is on the horizon from Autumn 2023 and some local authorities have started to develop their planning frameworks accordingly.

BNG can be delivered on-site, off-site or via statutory biodiversity credits, and is calculated using the approved Biodiversity Metric 3.1. Before the commencement of the property or infrastructure development, planning applicants must quantify the existing and proposed biodiversity values of their site and demonstrate that the intended gain exceeds the loss of the development project by at least 10%.

Carter Jonas has researched all 322 local planning authorities (LPAs) in England and analysed the extent to which BNG measures have been incorporated into Local Plans. The research collected data in December 2021 on planning policies, which expressly set a requirement for measurable net gain using a recognised metric.

Considering that Local Plan policies are still developing, it is unsurprising that the number of LPAs in England that have already implemented such policies is low. Only 5% have an adopted BNG policy and 23% have emerging policies.

But the West Midlands is significantly ahead, with 53% LPAs having BNG policy either adopted in Local Plans or emerging. The South East is also ahead at 32%.

Ten (3.2%) LPAs have gone above and beyond the 10% minimum. For example, the Greater Cambridgeshire Shared Planning service is seeking to introduce a minimum of 20%. Six of these LPAs are in the South East, two in the South West and one each in both the North West and East. We anticipate that many others will follow suit and mandate a level of net gain higher than 10%.