Editor at 16:58, 28 May 2026

2026-05-28T16:58:01Z

← Older revision		Revision as of 16:58, 28 May 2026
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		+	= Introduction =
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	Biodiversity net gain (BNG) is a planning requirement introduced under the Environment Act 2021 that requires new developments in England to deliver a measurable improvement in biodiversity compared to the pre-development baseline. From February 2024, a minimum 10% biodiversity net gain became mandatory for most major developments in England.		Biodiversity net gain (BNG) is a planning requirement introduced under the Environment Act 2021 that requires new developments in England to deliver a measurable improvement in biodiversity compared to the pre-development baseline. From February 2024, a minimum 10% biodiversity net gain became mandatory for most major developments in England.

−	~~Contents~~	+	= Legislative background =
−		+
−	~~# Legislative background~~	+
−	~~# The 10% BNG requirement~~	+
−	~~# How biodiversity is measured~~	+
−	~~# Delivering BNG~~	+
−	~~# BNG and the planning condition discharge process~~	+
−	~~# Exemptions~~	+
−	~~# Related articles~~	+
−		+
−	~~-----~~	+
−	1. Legislative background	+

	Schedule 14 of the Environment Act 2021 introduced mandatory BNG requirements in England. The requirement was phased in as follows:		Schedule 14 of the Environment Act 2021 introduced mandatory BNG requirements in England. The requirement was phased in as follows:
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	Prior to mandatory BNG, many LPAs in England included BNG requirements in local plans on a discretionary basis.		Prior to mandatory BNG, many LPAs in England included BNG requirements in local plans on a discretionary basis.

−	~~-----~~	+	= The 10% BNG requirement =
−	2. The 10% BNG requirement	+

	Developers must demonstrate that their scheme will deliver at least 10% more biodiversity value after development than was present on the site before. This net gain must be maintained for a minimum of 30 years.		Developers must demonstrate that their scheme will deliver at least 10% more biodiversity value after development than was present on the site before. This net gain must be maintained for a minimum of 30 years.
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	The requirement applies to the habitat units and hedgerow units present on the development site. A 10% net gain must be achieved across both habitat and hedgerow metrics independently.		The requirement applies to the habitat units and hedgerow units present on the development site. A 10% net gain must be achieved across both habitat and hedgerow metrics independently.

−	~~-----~~	+	= How biodiversity is measured =
−	3. How biodiversity is measured	+

	Biodiversity is quantified using the statutory biodiversity metric developed by Natural England (Metric 4.0 as of 2024). The metric calculates biodiversity units based on:		Biodiversity is quantified using the statutory biodiversity metric developed by Natural England (Metric 4.0 as of 2024). The metric calculates biodiversity units based on:
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	Assessments must be carried out by a suitably qualified ecologist. The metric is publicly available as a downloadable Excel tool from Natural England.		Assessments must be carried out by a suitably qualified ecologist. The metric is publicly available as a downloadable Excel tool from Natural England.

−	~~-----~~	+	= Delivering BNG =
−	4. Delivering BNG	+

	Biodiversity net gain can be delivered through three routes, applied in order of preference (the mitigation hierarchy):		Biodiversity net gain can be delivered through three routes, applied in order of preference (the mitigation hierarchy):
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	BNG habitats must be secured and managed for a minimum of 30 years through a legal agreement.		BNG habitats must be secured and managed for a minimum of 30 years through a legal agreement.

−	~~-----~~	+	= BNG and the planning condition discharge process =
−	5. BNG and the planning condition discharge process	+

	In most cases, BNG is secured through a combination of planning conditions and legal obligations. Pre-commencement conditions typically require submission and approval of:		In most cases, BNG is secured through a combination of planning conditions and legal obligations. Pre-commencement conditions typically require submission and approval of:
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	Post-development, a post-completion metric calculation and monitoring reports are usually required to demonstrate that the committed habitat units have been delivered.		Post-development, a post-completion metric calculation and monitoring reports are usually required to demonstrate that the committed habitat units have been delivered.

−	~~-----~~	+	= Exemptions =
−	6. Exemptions	+

	The following development types are exempt from mandatory BNG requirements:		The following development types are exempt from mandatory BNG requirements:

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Biodiversity net gain (BNG) is a planning requirement introduced under the Environment Act 2021 that requires new developments in England to deliver a measurable improvement in biodiversity compared to the pre-development baseline. From February 2024, a minimum 10% biodiversity net gain became mandatory for most major developments in England.

Contents

# Legislative background
# The 10% BNG requirement
# How biodiversity is measured
# Delivering BNG
# BNG and the planning condition discharge process
# Exemptions
# Related articles

-----
1. Legislative background

Schedule 14 of the Environment Act 2021 introduced mandatory BNG requirements in England. The requirement was phased in as follows:

* February 2024: Mandatory for major developments (10 or more dwellings, or over 0.5 hectares)
* April 2024: Extended to small sites (under 10 dwellings)
* April 2024: Extended to nationally significant infrastructure projects (NSIPs) under a separate regime

Prior to mandatory BNG, many LPAs in England included BNG requirements in local plans on a discretionary basis.

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2. The 10% BNG requirement

Developers must demonstrate that their scheme will deliver at least 10% more biodiversity value after development than was present on the site before. This net gain must be maintained for a minimum of 30 years.

The requirement applies to the habitat units and hedgerow units present on the development site. A 10% net gain must be achieved across both habitat and hedgerow metrics independently.

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3. How biodiversity is measured

Biodiversity is quantified using the statutory biodiversity metric developed by Natural England (Metric 4.0 as of 2024). The metric calculates biodiversity units based on:

* Habitat type
* Habitat condition (assessed as Poor, Moderate, or Good)
* Spatial risk multiplier (accounting for geographic risk to habitat creation)
* Temporal risk multiplier (accounting for the time required for habitat to reach its target condition)

Assessments must be carried out by a suitably qualified ecologist. The metric is publicly available as a downloadable Excel tool from Natural England.

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4. Delivering BNG

Biodiversity net gain can be delivered through three routes, applied in order of preference (the mitigation hierarchy):

# On-site habitat creation or enhancement: The preferred route. Habitat is created or improved within the development site boundary.
# Off-site habitat creation or enhancement: Where on-site delivery is not possible or sufficient, developers can create or enhance habitat on land outside the development site. This land must be secured through a Section 106 agreement or conservation covenant.
# Statutory biodiversity credits: As a last resort, developers can purchase statutory biodiversity credits from the government. Credits are priced to incentivise on-site and off-site delivery.

BNG habitats must be secured and managed for a minimum of 30 years through a legal agreement.

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5. BNG and the planning condition discharge process

In most cases, BNG is secured through a combination of planning conditions and legal obligations. Pre-commencement conditions typically require submission and approval of:

* A pre-development biodiversity metric calculation
* A biodiversity gain plan detailing how the 10% net gain will be achieved
* A habitat management and monitoring plan (HMMP)

Post-development, a post-completion metric calculation and monitoring reports are usually required to demonstrate that the committed habitat units have been delivered.

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6. Exemptions

The following development types are exempt from mandatory BNG requirements:

* Householder applications (extensions, loft conversions etc.)
* Development with a de minimis impact on biodiversity (no impact on priority habitats and less than 25 square metres of impact on non-priority habitat)
* Permitted development (unless a condition is imposed requiring BNG)
* Biodiversity gain sites themselves
* Development subject to a hybrid BNG approach under the NSIP regime
* Self-build and custom-build housing (fewer than 10 units)

[[Category:Planning_permission]] [[Category:Regulations]] [[Category:Sustainability]] [[Category:Conservation]]

Biodiversity net gain in England - Revision history

Editor at 16:58, 28 May 2026

Sarah jones: Created page with "Biodiversity net gain (BNG) is a planning requirement introduced under the Environment Act 2021 that requires new developments in England to deliver a measurable improvement in b..."