Mandatory biodiversity net gain requirements are around the corner and will affect most new “major developments” in England. Joanna Fox answers some commonly-asked questions on the requirements.
What are the biodiversity net gain requirements?
For planning applications submitted after the new rules come in, BNG requires at least a 10% increase in the biodiversity value of a site as a result of the development. The BNG must be maintained for at least 30 years.
Every affected planning permission in England will be deemed to have been granted subject to a BNG condition. This means that whether the BNG condition is actually written on the permission or not, the development cannot begin until a BNG plan has been submitted to and approved by the planning authority.
Which developments are affected?
Initially, the BNG requirement will apply to major developments, which includes residential development (10+ homes); buildings greater than 1,000 sq m; and development on sites of 1ha or more.
Exemptions include a de minimis exemption for developments which do not impact priority habitats. The exemption for small developments (ie those which are not major developments) ends in April 2024. Nationally significant infrastructure projects are exempt until late November 2025.
If you think your development is exempt from the BNG requirement, you need to state this in the planning application for the development.
What must be included in a BNG plan?
The plan provides information about how the BNG will be secured. This includes pre- and post-development plans showing on-site habitat, BNG register reference numbers for any off-site units that will be purchased, and proof of purchase for any statutory biodiversity credits.
The plan also needs to include a completed biodiversity metric calculation showing the pre- and post-biodiversity value of the site. Plans are required for each stage of a phased development.
Will this delay my start date?
The planning authority has eight weeks to approve or refuse your BNG plan (unless you agree a longer period). You may want to include a draft plan in your planning application and discuss it with the council as part of the application process to speed up approval of the plan.
What level of BNG is required?
The statutory minimum is a 10% increase. However, a number of councils will require a BNG greater than 10%, eg Guildford Borough Council requires at least 20% BNG.
How is the pre-development value determined?
The value is taken to be the biodiversity value of the development site on the date of the application. However, if a planning authority suspects that the biodiversity value of an on-site habitat has been damaged by activities carried out on or after 30 January 2020 (other than in accordance with planning permission), the baseline biodiversity value of the on-site habitat will be the biodiversity value of the site before the damage occurred.
What is the BNG hierarchy?
The BNG hierarchy requires adverse BNG effects of development to be mitigated in the following order of priority: on-site habitat enhancement; on-site habitat creation; off-site BNG; and, finally, by purchasing biodiversity credits. The planning authority must take into account how the BNG hierarchy is applied when determining whether to approve a BNG plan. Developers are incentivised to comply with the hierarchy as credits purchased under the statutory credit scheme can run into hundreds of thousands of pounds.
What is the spatial risk multiplier?
The Department for Environment, Food and Rural Affairs has published a biodiversity metric calculation tool which must be used to measure biodiversity value for the purposes of BNG.
Biodiversity is measured in biodiversity units. The BNG metric takes into account different factors including the location of off-site gains. This is done through a “spatial risk multiplier” which results in more biodiversity units being required the further away the off-site gain is to the development.
If a developer produces surplus biodiversity units on a site, it can register these on the national register and sell them to other developers, or use them as off-site BNG for its other schemes.
Does the BNG requirement apply to irreplaceable habitats?
No. Compensation for any impact on irreplaceable habitats will need to be agreed with the planning authority. The initial list of irreplaceable habitats will broadly mirror the list of examples already within the National Planning Policy Framework and will be updated following a consultation later this year.
How can I secure off-site mitigation for 30 years?
Section 106 agreements and conservation covenants both create an enforceable commitment to create or enhance habitat and manage the habitat for 30 years.
Conservation covenants are deeds entered into between a landowner and a responsible body (eg the council). They provide flexibility on who can enter into agreements and are not subject to the same restrictions on the type of obligations that can be secured by a section 106 agreement.
Conservation covenants may be entered into in addition to a contract for the acquisition of off-site units. Contracts could record the price and payment terms, number and type of units and obligation for the land manager (or developer with the land manager’s permission) to record the biodiversity units on the BNG sites register.
Joanna Fox is a senior associate in the planning and environment team at Ashurst LLP
