The Environment Act 2021 amended planning legislation to require planning permissions in England to be subject to a new pre-commencement condition requiring a 'biodiversity gain plan' ("BNG") for the development. That plan must ensure that the biodiversity value attributable to a development exceeds the pre-development biodiversity value of the onsite habitat by 10%. Note that the 10% requirement is not a cap - in practice, local planning policy requirements are likely to require more than that. This value can be delivered on-site, off-site, or through the purchase of 'biodiversity credits', or via a combination of these. There is a hierarchy, with on-site value being the preferred option. The associated habitat, or enhancement, must then be maintained for 30 years.

The delivery of BNG can range from the creation of new habitats such as chalk grasslands or meadows through to smaller enhancements such as the installation of bee bricks and green roofs. They will be calculated by reference to Biodiversity Metric 4.0.

BNG delivery can also be achieved in the construction of the built environment itself, through the inclusion of infrastructure like solar slate, ground source heat pumps, composting areas, and rainwater collection.

The idea that new projects should not only not harm biodiversity, but in fact positively contribute to it, represents a significant cultural shift. Putting it on a legislative footing and making it a pre-commencement requirement means that it must be taken seriously and front-loaded in the planning process.

The Government had originally intended to implement BNG in November 2023, but this was delayed until January 2024 for major schemes, and April 2024 for small sites. NSIPS are expected to be subject to a BNG requirement from 2025.

The Government had promised a raft of guidance for developers and LPAs on how BNG will operate in practice. This has now been published (Biodiversity net gain - GOV.UK (www.gov.uk)) ahead of the arrival of BNG at the start of next year.

Ultimately, with such a fundamental new requirement being added to the planning process, the key question will be how quickly it can bed in without significant disruption to the delivery of new development. In particular, there will be real pressure on (already overstretched) local planning authorities. They will be tasked with dealing with biodiversity gain plans submitted pre-commencement, with any delays in approvals meaning delays in starting on site. The forthcoming increase in planning application fees (by 35% for applications for major development and 25% for all other applications) is a start but resourcing challenges are likely to remain.

We will continue to keep you updated as and when further guidance is issued.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.