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Does My Site Require Biodiversity Net Gain?

In 2024, the BNG legislative and policy landscape is fast-moving. In this article we will provide up to date guidance on determining if BNG applies to a development site.

We will firstly discuss whether BNG is required for a site under The Environment Act 2021, and then discuss the influence of the National Planning Policy Framework and Local Planning Policy.

What Is Biodiversity Net Gain (BNG)?

Biodiversity Net Gain (BNG) can be defined as an approach to development that ensures habitats for wildlife are in a measurably better state post-development than prior to development.

The BNG can be delivered either entirely on-site, or part on-site and part off-site, or via the purchasing of statutory biodiversity credits. The BNG framework requires preference to be given firstly to on-site delivery. In all cases where mandatory BNG applies, the development must result in an overall ‘net gain’ relative to the pre-development biodiversity value.

The post-development percentage uplift of BNG required under The Environment Act 2021 is 10%, relative to the pre-development biodiversity value of the site. A range of qualitative conditions must also be met to claim BNG at a site, and BNG does not change the existing obligations for planning applications regarding ecology and biodiversity.

The Environment Act 2021

For all development defined as ‘Major’, as of the 12th of February 2024, delivering a 10% Biodiversity Net Gain is a mandatory legal requirement. Major development includes:

  • the provision of dwellinghouses where—
    • the number of dwellinghouses to be provided is 10 or more; or
    • the development is to be carried out on a site having an area of 0.5 hectares or more and it is not known whether the development is 10 or more dwellinghouses;
  • the provision of building(s) where the floor space to be created by the development is 1,000 square metres or more;
  • development carried out on a site having an area of 1 hectare or more;
  • the winning and working of minerals or the use of land for mineral-working deposits;
  • waste development.

For small developments BNG will become mandatory from 2 April 2024. These include:

  • residential development of 1 to 9 dwellings on a site of an area 1 hectare or less, or if the number of dwellings is unknown, the site area is less than 0.5 hectares;
  • commercial development where floor space created is less than 1,000 square metres or the total site area is less than 1 hectare;
  • development that is not the winning and working of minerals or the use of land for mineral-working deposits;
  • development that is not waste development.

Some sites are exempt from the BNG requirements under The Environment Act. These include:

  • existing planning applications, where planning permission was made prior to 12 February 2024
  • development that does not impact priority habitat and impacts less habitats than:
    • 25 square metres (5m by 5m) of on-site habitat; or
    • 5 metres of on-site linear habitats such as hedgerows;
  • householder applications;
  • self-build and custom build applications, meeting all of the following criteria:
    • no more than 9 dwellings; or
    • on a site no larger than 0.5 hectares; or
    • consists exclusively of dwellings that are self-build or custom house building;
  • developments that are granted planning permission by a development order (including permitted development rights).

The National Planning Policy Framework (NPPF)

The NPPF (updated 12 February, 2024) sets out that ‘Planning policies and decisions should contribute to and enhance the natural and local environment by: […] minimising impacts on and providing net gains for biodiversity, including by establishing coherent ecological networks that are more resilient to current and future pressures’.

Local Planning Authorities can request that developments deliver a measurable Biodiversity Net Gain via a Biodiversity Metric even where The Environment Act 2021 does not apply, using the government’s planning policies set out in the NPPF alongside local planning policy. In these scenarios, and in the absence of local planning policy requiring a minimum BNG percentage, appeals have shown any BNG on site (i.e., above 1%), would meet the requirement.

Local Planning Policy

At a local level, planning policy can require that developments deliver in excess of the 10% Biodiversity Net Gain requirement under The Environment Act 2021. Examples of areas where an above 10% BNG policy is in draft, emerging, or adopted planning policy are:

  • The Royal Borough of Kingston upon Thames Council – 30% BNG
  • Greater Cambridge – 20% BNG
  • East Devon District Council – 20% BNG
  • Canterbury City Council – 20% BNG
  • Maidstone Borough Council – 20% BNG
  • Medway Council – 20% BNG
  • Swale Borough Council – 20% BNG
  • London Borough of Richmond upon Thames – 20% BNG
  • Mole Valley District – 20% BNG
  • Surrey Heath Borough Council – 20% BNG
  • Swindon Borough Council – 20% BNG

Key Conclusions

When determining if a development project will be required to deliver a Biodiversity Net Gain and the relevant percentage required, it is critical to consider both national and local level requirements, including any planning advice available from the Local Planning Authority.

Elton Ecology Ltd have extensive experience in securing Biodiversity Net Gain for development projects including Major residential and commercial development. Contact Us to discuss your project.