The publication of further regulations last week marks the final steps required to introduce mandatory biodiversity net gain (BNG). From 12 February 2024 most developers will need to provide a BNG of at least 10% on new planning applications for development that result in a loss or degradation of habitat.  

Planning consents granted pursuant to applications made after 12 February 2024 will be subject to a condition that development may not begin until a  biodiversity gain plan (BNG plan) has been submitted to and approved by the Local Planning Authority. There are limited exceptions, including householder applications and developments of below 25 square meters of habitat. "Small" sites will not be subject to the new requirements until 2 April 2024.  

The BNG plan will only be approved if the biodiversity value attributable to the development exceeds the pre-development biodiversity value of habitat on the land to which the plan relates by at least 10%. Developers will therefore want to ensure that a BNG plan is prepared and assessed at any early stage in the acquisition / planning process.  

BNG requirements can be met by enhancing the biodiversity of the development site itself, or offsite on land owned by the developer. Alternatively, where this is not possible or practicable the developer may satisfy its BNG requirements offsite on land owned and operated by a BNG land  manager and listed on a public BNG register, or by the purchase of statutory biodiversity credits.   

Where the BNG plan details onsite or offsite biodiversity enhancement, the enhancement must be maintained for at least 30 years after the development is completed, with such obligation secured by a s106 planning agreement or a conservation covenant (as appropriate). When calculating the mandatory 10% BNG, a statutory "biodiversity metric" will be used, and will give greater weight to improvements onsite, or within the same local authority (if off site), as a result disincentivising the purchase of statutory biodiversity credits.  

BNG is a mandatory requirement and, accordingly , will be an essential consideration on site acquisition and development. BNG can also provide a potential source of revenue for land owners, particularly those with rural and / or biodiverse sites.  Whilst there are still considerable areas of uncertainty, particularly surrounding the form of conservation covenants and enforcement, we are seeing the market respond, with the development of products to assist developers ascertain the current and projected ecological status of a site by way of a cost effective screening report.