Guide Biodiversity Net Gain

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1. Biodiversity Net Gain in the Planning Process

What is Biodiversity Net Gain?

Biodiversity Net Gain (BNG for short) is an approach to planning and land management that ensures development will have a positive impact on biodiversity. This new planning requirement came into force in England in 2024. The principle of BNG requires developments to provide or enhance habitats for wildlife such that the environment is left in a measurably better state than it was prior to the development taking place.

Biodiversity Net Gain will transform how developments are planned, designed, built and maintained. It has the potential to bring benefits to both people and wildlife such as providing communities with beautiful natural green spaces and bringing back wildlife. It also has potential for improved air quality, flood management and soil stability.

BNG was introduced by Schedule 7A of the Town and Country Planning Act 1990, inserted by the Environment Act 2021. This is referred to as biodiversity net gain in Planning Practice Guidance to distinguish it from other or more general biodiversity gains.

East Devon District Council Requirements

Our guidance is strongly underpinned by Biodiversity Net Gain Good Practice Principles for Development (Construction Industry Research and Information, 2016). These principles provide an industry standard framework to ensure that Biodiversity Net Gain is much more than a box ticking exercise or a way of achieving biodiversity-by-numbers.

Currently, we are seeking a minimum 10% Biodiversity Net Gain (i.e. 110% of pre-development biodiversity value) through use of the Statutory Defra Biodiversity Metric or the Small Site Metric; the net gain must be meaningful as well as measurable. From the earliest stage, proposals for new development should involve competent and experienced ecologists contributing to the various design and layout options to enable the minimum 10% Biodiversity Net Gain to be delivered on site. Where this is clearly demonstrated not to be feasible (to be agreed with the Local Planning Authority) it may involve offsite compensation.

To ensure the requirements for Biodiversity Net Gain are achieved, it is important that these issues are addressed at a very early stage in the application process. Consequently, applicants are encouraged to engage in the Council’s Pre-application Advice Service.

Even where planning application sites are exempt from the national mandatory 10% BNG requirement, EDDC still expects applicants to achieve a net gain and other biodiversity enhancements, in line with the National Planning Policy Framework (2023) and relevant local plan policy.

BNG and existing wildlife legislation and policy

BNG is additional to, and does not replace, existing wildlife legislation, policy, and guidance, e.g., Environmental Impact Assessment (EIA), Habitats Regulation Assessment (HRA) etc.  Therefore, development proposals will still be subject to the same biodiversity assessment criteria for protected or important nature conservation sites and irreplaceable habitats.

Biodiversity Net Gain only relates to habitats so does not take rare, notable, and protected species into consideration. It will therefore be necessary to demonstrate how these species have been considered, protected, and supported through the Ecological Impact Assessment (EcIA) process to address legal requirements and to meet Policy EN5 (Wildlife Habitats and Features) of the Adopted East Devon Local Plan.

The presence of protected species is expected to influence the design, layout and specification of the proposals for habitat retention, enhancement and creation and this should be clearly demonstrated in the planning application documentation.

Biodiversity Net Gain in the Planning Process

Most planning applications, with a few exemptions, will be required to demonstrate a minimum 10% Biodiversity Net Gain under the Environment Act 2021.

BNG should be considered early in the planning process to ensure it is factored into site selection and design, as well as considering botanical and protected species survey windows which are seasonally dependent.  Applicants are encouraged to use the Council’s Pre-application Advice Service to further understand the specific requirements in relation to their site.

BNG is a mandatory requirement, and has had a phased introduction as follows:

  • Major development: 12 February 2024
  • Small-scale development: 2 April 2024
  • Nationally Significant Infrastructure Projects: November 2025

Developers must assess the pre- and post- development habitat value of their proposals to establish that a minimum 10% gain can be achieved prior to submitting a planning application. The 10% gain is required in legislation and therefore there is no scope for LPAs to allow a reduction on viability grounds.

GOV.UK biodiversity net gain planning practice guidance sets out the framework of how BNG will be applied in the planning process. The Devon County Council website also provides guidance for applications made in Devon and should be followed, unless stated otherwise.

Exemptions

Certain types of development are exempt from mandatory BNG as set out in the Biodiversity Gain Requirements (Exemptions) Regulations 2024. Before submitting an application, check whether the development may be exempt. In the following circumstances, the national biodiversity gain condition will not apply:

  • retrospective planning permissions made under section 73A
  • section 73 permissions where the original permission which the section 73 relates to was either granted before 12 February 2024 (for major development) or 2 April 2024 (for minor development). Or the application for the original permission was made before 12 February/2 April 2024
  • Planning permissions which have been granted through other routes to permission, including:
    • Local Development Orders
    • Simplified Planning Zones
    • Neighbourhood Development Orders
    • Successful enforcement appeals
    • Deemed planning permission
  • Permission in Principle applications
  • Householder development
  • Development subject to the de minimis exemption
  • Self-build and custom build development. Find out more what qualifies as Self-build and custom housebuilding
  • Urgent Crown development granted permission under section 293A of the Town and Country Planning Act 1990
  • Development of a biodiversity net gain site
  • Development related to the high speed railway transport network.