Planning · England
Biodiversity net gain: 10% more habitat before you build
Biodiversity net gain (BNG) is a condition attached by law to planning permissions in England.
Development may not begin until the planning authority approves a plan showing at least a 10% gain in biodiversity value.
It is a planning rule, not a company reporting duty.
The rule
What the 10% actually measures
The objective is met where the biodiversity value attributable to the development exceeds the pre-development value of the on-site habitat by at least 10%.
That value is a total: the on-site post-development value, plus any registered off-site gain allocated to the development, plus any statutory credits bought.
Every planning permission in England is deemed to be granted subject to the condition that development may not begin until a biodiversity gain plan has been submitted and approved.
Value is measured in biodiversity units with the statutory metric; Defra says any version of the statutory metric tools may be used.
Area, hedgerow and watercourse units are separate types, and the 10% applies to each type.
When it applies
Four start dates, not one
| Development | BNG applies | Instrument |
|---|---|---|
| Major development (TCPA Part 3) | Applications from 12 February 2024 | SI 2024/44 |
| Small sites (non-major development) | Applications from 2 April 2024, when a temporary exemption lapsed | SI 2024/47 reg 3 |
| Crown development (TCPA Part 13) | From 1 May 2025 | SI 2025/447 |
| Nationally significant infrastructure projects | DCO applications made on or after 2 November 2026 | Biodiversity gain statements |
For NSIPs, Schedule 2A to the Planning Act 2008 says the percentage in a gain statement “must be at least 10%”: a floor, not a fixed figure.
Exemptions
Who is exempt since 6 August 2026
| Exemption | Test | Status |
|---|---|---|
| Householder applications | Extensions, conservatories, loft conversions and similar | Live |
| De minimis | No priority habitat affected; under 25 m² of habitat and under 5 m of hedgerow | Live |
| Sites of 0.2 hectares or less | Red line boundary of 0.2 ha or below; no priority habitat affected | New from 6 August 2026 |
| Temporary development | Wholly temporary, for no more than five years; no priority habitat affected | New from 6 August 2026 |
| High speed rail; biodiversity gain sites | As defined in SI 2024/47 | Live |
| Self-build and custom build | Up to 9 dwellings on up to 0.5 ha | Omitted for applications from 6 August 2026 |
Defra’s guidance says the new exemptions apply to applications made from 6 August; applications already submitted stay under the earlier rules.
Permitted development, granted by a development order rather than an application, is outside Schedule 7A.
The hierarchy
On site first, credits last
Article 37A of the Development Management Procedure Order 2015 sets the biodiversity gain hierarchy “in the following order of priority”.
For high-distinctiveness habitat, avoid harm first and mitigate what cannot be avoided.
For major development, compensate in order: enhance on-site habitat, create on-site habitat, use registered off-site gain, and only then buy statutory credits.
For non-major development applied for from 6 August 2026, on-site enhancement, on-site creation and off-site gain rank equally, with credits still last.
A gain plan must give reasons for any departure from that order, and the authority must take the reasons, or their absence, into account.
The planning authority has 8 weeks to decide a gain plan unless a longer period is agreed in writing.
Off-site gain and credits
What off-site gain and credits cost
| Statutory credit tier | Price per credit |
|---|---|
| A1 | £42,000 |
| A2 | £48,000 |
| A3 | £66,000 |
| A4 | £125,000 |
| A5 | £650,000 |
| H (hedgerow) | £44,000 |
| W (watercourse) | £230,000 |
A spatial risk multiplier applies to statutory credits, so a developer buys two credits for every biodiversity unit; the multiplier is not in the prices above, and VAT is not charged.
No statutory instrument fixes these prices: section 101 of the Environment Act 2021 lets the Secretary of State sell credits and requires the price to be published.
An off-site gain must sit on a site entered in Natural England’s register, which costs £639 to register, and be secured by a legal agreement.
That agreement lasts at least 30 years from completion of the habitat enhancement; for significant on-site gains, the 30 years run from completion of the development.
BNG sits on the development, not in the annual report.
The statutory biodiversity reporting duty in section 40A of the NERC Act 2006 binds local and planning authorities; company nature disclosure is voluntary, under frameworks such as the TNFD.
Frequently asked
Biodiversity net gain, answered
What is biodiversity net gain?
Biodiversity net gain is a planning rule in England.
Schedule 7A to the Town and Country Planning Act 1990, inserted by the Environment Act 2021, makes every planning permission subject to a deemed condition that development may not begin until the planning authority has approved a biodiversity gain plan showing at least a 10% gain in biodiversity value over the site’s pre-development value.
Is biodiversity net gain mandatory?
Yes, for planning permissions in England that are not exempt.
It applied to applications made under Part 3 of the 1990 Act from 12 February 2024, to small sites from 2 April 2024, to Crown development from 1 May 2025, and to nationally significant infrastructure projects for DCO applications made on or after 2 November 2026.
Does the 10% have to be delivered on site?
No. Schedule 7A counts the total of on-site post-development value, any registered off-site gain allocated to the development and any statutory credits bought.
The order of preference is set by the gain hierarchy in article 37A of the Development Management Procedure Order: on-site first, statutory credits last.
Which developments are exempt from BNG?
Householder applications; de minimis development that affects no priority habitat and less than 25 square metres of habitat (or 5 metres of hedgerow); high speed rail; biodiversity gain sites; and, for applications made on or after 6 August 2026, sites of 0.2 hectares or less that affect no priority habitat and temporary development of up to five years.
Permitted development is outside the regime.
Is self-build exempt from biodiversity net gain?
Not for applications made on or after 6 August 2026.
SI 2026/790 omitted the self-build and custom build exemption from that date. It still applies to applications made before 6 August 2026.
How much do statutory biodiversity credits cost?
Defra’s list, last updated 2 June 2026, runs from £42,000 for an A1 credit to £650,000 for A5, with £44,000 for hedgerow and £230,000 for watercourse credits.
A spatial risk multiplier means two credits are needed for every biodiversity unit, and VAT is not charged.
Credits are the last resort in the hierarchy.
How long must BNG habitat be maintained?
At least 30 years where it counts.
Schedule 7A applies the 30-year condition to significant on-site enhancements, and Defra’s legal agreement guidance requires off-site gains to be secured for at least 30 years from completion of the enhancement. It is not a blanket 30-year duty over every site.
Does biodiversity net gain apply in Wales or Scotland?
No. Schedule 7A is confined to grants of planning permission in England.
Wales, Scotland and Northern Ireland have their own planning systems.
Do companies have to report on biodiversity net gain?
Not in their annual reports.
BNG is a planning condition on a development.
The statutory biodiversity reporting duty in section 40A of the NERC Act 2006 falls on local authorities and planning authorities, not companies; company biodiversity disclosure in the UK is voluntary, for example under the TNFD recommendations.
Sources
Primary sources
Every date, percentage and price on this page is from the legislation or from Defra and Natural England.
- legislation.gov.ukTown and Country Planning Act 1990, Schedule 7A
The 10% objective (¶2), the 30-year condition (¶9) and the deemed planning condition (¶13).
- legislation.gov.ukSI 2024/44 (Environment Act 2021 Commencement No. 8 and Transitional Provisions)
Schedule 7A in force for Part 3 applications from 12 February 2024.
- legislation.gov.ukSI 2024/47, regulations 3 to 8 (the exemptions)
The exemptions; the small-sites carve-out to 2 April 2024.
- legislation.gov.ukSI 2026/790 (amendments and transitional provisions)
From 6 August 2026: the 0.2 hectare and temporary exemptions; self-build exemption omitted.
- legislation.gov.ukSI 2015/595 (DMPO), Part 7A
The biodiversity gain hierarchy (art 37A) and the eight-week determination (art 37D).
- legislation.gov.ukEnvironment Act 2021, section 101
The power to sell statutory biodiversity credits and publish their price.
- DefraStatutory biodiversity credit prices
Prices per credit (last updated 2 June 2026); the spatial risk multiplier; no VAT.
- DefraBiodiversity net gain: exempt developments
The 6 August 2026 exemptions in the owner’s words.
- DefraStatutory biodiversity metric tools and guides
Any version of the statutory tools may be used.
- Defra / Natural EnglandRegister a biodiversity gain site
£639 to register a site; a legal agreement for at least 30 years.
- DefraSubmit a biodiversity gain plan
What to attach; the authority has 8 weeks.
- DefraEnter a legal agreement for biodiversity net gain
At least 30 years from completion of the development or of the enhancement.
- legislation.gov.ukSI 2026/492 and Planning Act 2008, Schedule 2A
NSIP provisions in force 7 May 2026; the percentage “must be at least 10%”.
- GOV.UKBiodiversity gain statements for nationally significant infrastructure projects
The ten statements; DCO applications from 2 November 2026.
- legislation.gov.ukNERC Act 2006, section 40A
The biodiversity reporting duty, on public authorities only.