Biodiversity Net Gain transition period

When preparing a planning application that includes the requirement for Biodiversity Net Gain (BNG), the specifics can often be blurry, leading to confusion regarding what percentage of net gain is actually required for your site. We are now waiting for 10% net gain in biodiversity to become mandatory throughout England. How should the requirement for BNG be approached during this period of transition?

Why are we in a transitional period for BNG?

BNG is the requirement for planning applications to provide measurable gains in biodiversity when developing sites. This is achieved through habitat creation, enhancement and restoration on the development site, or by providing habitat creation off site. Percentage gains and losses are calculated within a specialised metric calculator tool.

The Environment Act 2021 became law in November 2021. A gain in biodiversity of 10% is a fundamental element of the new Act. We are now in a period of transition whereby Local Planning Authorities (LPAs) are obligated to include the requirement for at least 10% BNG to their local plans. BNG at 10% will become mandatory when secondary legislation is provided in November 2023. However, it is the decision of LPAs whether to include a requirement for net gain in advance of this date. Some LPAs have had planning policies related to BNG for some time, with some differences in the extent of gain required.

The National Planning Policy Framework states planning policies should seek to conserve biodiversity by “minimizing impacts on and providing net gains in biodiversity”. This guidance does not state that net gains in biodiversity should be demonstrated using a metric tool, but many councils have already adopted the use of such tools.

Do all LPAs require developments to demonstrate 10% net gain?

LPAs that request BNG differ in their percentage requirements. Some councils will request ‘a gain’ which could technically be satisfied by only a marginal positive gain, whereas other LPAs may accept planning applications without the use of a metric, provided that the actions intended to achieve a gain in biodiversity are clearly stated and are very likely to result in the improvement of biodiversity on site. It should be noted however that these sites are usually very simple and would only be acceptable for specific LPAs. Other LPAs already have planning policies related to 10% BNG, and there has been the suggestion that some LPAs will begin to request gains of up to 20% or more in the future.

There are instances where developments are exempt from demonstrating net gain, including; permitted development, brown field sites (that meet specific criteria), some nationally significant infrastructure projects and irreplaceable habitats such as ancient woodland.

If my LPA doesn’t specify that BNG is required, should I bother?

Providing BNG already features within planning legislation, specifically the National Planning Policy Framework as mentioned above. Ecology by Design always recommend future-proofing sites by considering the requirement for BNG from the early stages of planning application preparation. As discussed in further detail below, the approach of LPAs can change, especially during this transitional period between the Royal Assent of the Environment Act 2021, and the enactment of mandatory 10% BNG nationwide.

Can LPAs change their requirement for BNG?

BNG can be requested for any application that qualifies under the Town and Country Planning Act 1990. Section 55 of the Town and Country Planning Act states the definition of a ‘development’ which would therefore require planning permission to proceed legally. It includes building operations, material changes of land use, engineering and mining operations, operations requiring a professional builder and the subdivision of buildings. This includes applications at later stages, including reserved matters applications, detailed applications and non-material amendment applications. Therefore the requirement for BNG could be triggered at a later stage of an application, even if there was no mention at the time of receiving outline consent. Ecology by Design have assisted with examples of these later requirements for BNG, and it is therefore recommended that the potential for net gain is considered during the early stages of the planning application. This is especially important for developments that will not achieve BNG on site due to the habitats present or the number of houses proposed, an action plan should be in place to ensure that the application can still be feasible when BNG is included. It is expected that detailed guidance will be provided in November 2023 which may include exclusions but at this stage, any proposed development could require BNG at any stage of the application process.

It is also worth considering that providing BNG on a development site will always be preferable to LPAs, even if they do not specify the requirement within their planning policies at this stage. The National Planning Policy Framework encourages the support of applications that secure net gains in biodiversity; therefore it is likely to put the application in a positive light.

Ecology by Design have the experience to guide you through the BNG process from the earliest stages, and as standard will investigate the specific requirements of the LPA which you will be applying to. We can then work alongside developers, architects, planners and landscape designers to provide a feasible outcome for your site. Forward planning is essential when navigating the new requirements for Biodiversity Net Gain.

Should you need any more guidance on biodiversity offsetting, please contact us. Our knowledgeable team of ecology experts would be happy to help. You may also find more advice and insight into other ecology services in our blog.