Biodiversity net gain: exempt developments
A guide to the types of development that will be exempt from the mandatory biodiversity net gain (BNG) requirements.
Applies to England
Biodiversity net gain (BNG) is mandatory from 12 February 2024.
The developments listed in this guide are exempt from BNG rules.
Existing planning applications
If a planning application for a development was made before day one of mandatory BNG on 12 February 2024, the development is exempt from BNG.
Variations of planning permission
Transitional arrangements also apply for variations to existing planning permissions. There is more information in the planning practice guidance.
Developments below the threshold
A development that does not impact a priority habitat and impacts less than:
- 25 square metres (5m by 5m) of on-site habitat
- 5 metres of on-site linear habitats such as hedgerows
A development ‘impacts’ a habitat if it decreases the biodiversity value.
Find out more about this exemption.
Householder applications
These are applications made by householders as defined within article 2(1) of the Town and Country Planning (Development Management Procedure) (England) Order 2015.
It includes, for example, small projects like home extensions, conservatories or loft conversions.
Self-build and custom build applications
An exemption applies to this type of development when it meets all the following conditions:
- consists of no more than 9 dwellings
- on a site that has an area no larger than 0.5 hectares
- consists exclusively of dwellings that are self-build or custom housebuilding as defined in section 1(A1) of the Self-build and Custom Housebuilding Act 2015
Biodiversity gain site
Developments undertaken mainly for the purpose of fulfilling the BNG planning condition for another development are exempt.
High speed rail transport network
An exemption applies to any development forming part of, or ancillary to, the high-speed railway transport network, comprising connections between all or any of the places or parts of the transport network specified in section 1(2) of the High Speed Rail (Preparation) Act 2013.
Other exemptions
The following are exempt by the Environment Act 2021:
- urgent crown developments
- developments that are granted planning permission by a development order (including permitted development rights)
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Last updated 2 April 2024 + show all updates
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Removed 'small developments' from the exemptions list as small developments are subject to BNG from 2 April 2024.
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Updated box at top of page to state that biodiversity net gain (BNG) is mandatory from 12 February 2024 and removed the 'draft guidance' label. Also provided more clarity around the 'Developments below the threshold' exemption. Added other exemptions.
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Updated to clarify that a small site does not fall into the category of a major development, as defined in article 2(1) of the Town and Country Planning (Development Management Procedure) (England) Order 2015.
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First published.