Biodiversity net gain (BNG) regulations and implementation; Government response

[edit] Introduction

In December 2018, the Environment Secretary announced a government consultation on mandating biodiversity net gain in development. The plan was to require developers to ensure habitats for wildlife are enhanced and left in a measurably better state than pre-development. The consultation ran until February 2019.

In January 2022 a consultation on biodiversity net gain (BNG) regulations and implementation was launched and ran for 12 weeks. It was supported by a consultation document, market analysis study, impact assessment for Nationally Significant Infrastructure Projects (NSIPs), and a report detailing the results of an economic appraisal for major infrastructure projects. It covered the 3 main areas:

• The scope of the Town and Country Planning Act 1990 (TCPA) requirement and proposed exemptions; development within statutory designed sites, and irreplaceable habitats.
• Applying BNG to different types of development, including phased development; small sites,
• How mandatory BNG will work for TCPA development and an example biodiversity gain plan.

In February 2023, with the consultation complete, the Government published outcomes and responses to the programme in 3 parts;

On 28 May 2025, phrased as the Government backs SME builders to get Britain building, plans were announced to allow smaller housebuilders to benefit from simpler rules with new reforms across land, regulation and finance. This included proposals for eased Biodiversity Net Gain (BNG) requirements for small sites, defined as developments of up to nine homes, as well as 'simplified BNG rules' for a newly established medium sized site category, of between ten to 49 homes.

[edit] Defining the scope of the BNG requirement for Town and Country Planning Act 1990 development

[edit] Exemptions

The Environment Act 2021 already makes exemptions for permitted development and urgent crown development. The biodiversity metric, allows for temporary impacts that can be restored within 2 years to be excluded from calculations. It also gives existing sealed surfaces (such as tarmac or existing buildings) a zero score, meaning that these surfaces are effectively exempted from the percentage gain requirement. Proposed exemptions are:

• Development impacting habitat of an area below a ‘de minimis’ threshold of 25 metres squared, or 5m for linear habitats such as hedgerows.
• Householder applications.
• Biodiversity gain sites (where habitats are being enhanced for wildlife).

In addition to the exemptions above, it is proposed that small scale self-build and custom housebuilding will be exempt.

[edit] Development within statutory designated sites for nature conservation

Development on statutory sites designated for nature conservation will not be exempt from the BNG requirement.

[edit] Irreplaceable habitat

Respondents expressed strong agreement with the 5 proposals for irreplaceable habitats:

• To exclude irreplaceable habitat from the quantitative mandatory biodiversity gain objective.
• To include a requirement to submit a version of a biodiversity gain plan for development (or component parts of a development) on irreplaceable habitats to increase proposal transparency.
• To allow the use of the biodiversity metric to calculate the value of enhancements of irreplaceable habitat where there are no negative impacts to irreplaceable habitat.
• To use the powers in BNG legislation to set out a definition of irreplaceable habitat, which would be supported by guidance on interpretation.
• To provide guidance on what constitutes irreplaceable habitat to support the formation of bespoke compensation agreements.

[edit] Applying the biodiversity gain objective to different types of development

• Phased development and development subject to subsequent applications - additional biodiversity gain information across the whole site on a phase-by-phase basis, approval of a biodiversity gain plan prior to commencement of each phase.
• Small sites and reducing the burdens of the process, provision of a small sites metric for developments which meet its size and absence of priority habitats criteria, defined as: Residential where the number of dwellings to be provided is between one and nine inclusive on a site having an area of less than one hectare (or 0.5 hectares if dwelling nos not known). Non-residential where created floor space is less than 1,000 square metres or where the site area is less than one hectare.
• Nationally Significant Infrastructure Projects (NSIPs), in general no exemptions, other than the provision made for development on irreplaceable habitats to help create consistency between different project types.

[edit] How the mandatory BNG requirement will work for Town and Country Planning Act 1990 development

In quite a detailed section the requirements are described under 9 key headings;

• Biodiversity gain plan.
• Off-site biodiversity gains.
• The market for biodiversity units.
• Habitat banking.
• The biodiversity gain site register.
• Additionality
• Statutory biodiversity credits.
• Reporting, evaluation, and monitoring.
• Local planning authorities (LPAs).

This article is based on "Consultation outcome,Government response and summary of responses" from the Gov.uk website updated 21 February 2023. For further information on the theme also visit the collection "biodiversity net gain".

[edit] Related articles on Designing Buildings

• Biodiversity.
• Biodiversity gain.
• Biodiversity in the urban environment.
• Biodiversity offsetting.
• Biophilia.
• BREEAM Enhancing site ecology.
• BREEAM Long term impact on biodiversity.
• Ecological network.
• Ecological impact assessment.
• Ecology.
• Ecology compensation.
• Ecology connectivity.
• Environmental impact assessment.
• Environmental net gain.
• Green infrastructure.
• Green roofs.
• Nature improvement area.
• Natural environment white paper.
• Sustainable development toolkit.
• The future of green infrastructure.

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