BNG Non-Major Development Off-Site Hierarchy August 2026: What Changes Now

Last updated: August 20, 2026

Quick Answer: From 6 August 2026, the BNG non-major development off-site hierarchy changed fundamentally. Under the Biodiversity Gain (Town and Country Planning) Amendments Regulations 2026, registered off-site biodiversity units now sit on equal footing with on-site habitat enhancement for non-major schemes. Developers no longer need to demonstrate they have exhausted on-site options before purchasing off-site units. This is a distinct change from the small-site exemption and applies to non-major schemes that still carry a mandatory BNG obligation.

Key Takeaways

• From 6 August 2026, on-site and off-site BNG delivery are equally valid starting points for non-major development, the old sequential hierarchy no longer applies to these schemes [6]
• Non-major development means fewer than 10 dwellings, less than 1,000 sqm of floorspace, or a site area under 1 hectare [5]
• The strict on-site-first hierarchy is retained for major development only
• Statutory credits remain the last resort for all development types, this has not changed
• The change is separate from the 0.2 ha small-site exemption and self-build exemption removal, which are distinct policy instruments [3]
• Developers can now go straight to the Biodiversity Gain Site Register to source off-site units without first justifying why on-site delivery was impractical
• Off-site units are typically cheaper and faster to arrange than statutory credits, but more expensive than well-designed on-site delivery
• Professional bodies still recommend good-practice sequencing (avoid, minimise, restore, offset) as a design principle, even where it is no longer legally required [10]
• Local planning authorities may still issue advisory notes encouraging on-site consideration, but cannot require it as a precondition for non-major schemes [4]

What Is BNG Non-Major Development Off-Site Hierarchy?

The BNG non-major development off-site hierarchy refers to the order in which developers of smaller schemes must consider their options for delivering the mandatory 10% biodiversity net gain. Before 6 August 2026, that hierarchy required on-site enhancement to be explored and, in practice, largely exhausted before off-site units could be used. After 6 August 2026, the hierarchy for non-major development was relaxed so that on-site and off-site delivery are treated as equivalent options at the same step.

This matters because many small developers found the old sequential approach burdensome and disproportionate for constrained urban sites where meaningful on-site habitat creation was genuinely limited. The change removes that administrative friction without abandoning the underlying 10% BNG target [6].

For a broader overview of how BNG works, see our biodiversity net gain guidance.

BNG Non-Major Development Off-Site Hierarchy August 2026: What Changed and Why

The Biodiversity Gain (Town and Country Planning) Amendments Regulations 2026 formalised the equal weighting of on-site and off-site delivery for non-major schemes. This followed Defra's twin consultations, which identified that the strict sequential hierarchy was creating disproportionate compliance costs for smaller developers and, in some cases, producing poor ecological outcomes where developers shoehorned token on-site planting onto unsuitable sites simply to satisfy the hierarchy [9].

What the old hierarchy looked like for non-major development:

1. On-site habitat creation and enhancement (required first)
2. Off-site registered units (only after on-site options were exhausted)
3. Statutory biodiversity credits (last resort)

What the new hierarchy looks like from 6 August 2026:

1. On-site habitat creation and/or registered off-site units (equal footing, either or both)
2. Statutory biodiversity credits (still last resort)

The practical effect is significant. A developer of a nine-unit housing scheme on a tight brownfield site can now go straight to purchasing registered off-site units without writing a justification for why on-site delivery was impractical [6].

Pre- vs Post-6 August 2026 Hierarchy Comparison for Non-Major Development

Who Needs to Follow BNG Non-Major Development Off-Site Hierarchy Requirements?

The relaxed hierarchy applies to any development that meets all three conditions: it is non-major, it is in England, and it carries a mandatory BNG obligation under the Environment Act 2021. Non-major development is defined as [5]:

• Fewer than 10 dwellings (residential)
• Less than 1,000 sqm of new floorspace (commercial)
• A site area under 1 hectare

If a scheme exceeds any of these thresholds, it is classified as major development and the strict sequential hierarchy remains in force. Major developers must still demonstrate on-site enhancement is maximised before off-site units are used.

Who this does not apply to:

• Schemes below 0.2 ha that qualify for the small-site exemption (they have no BNG obligation at all)
• Permitted development that falls outside the mandatory BNG regime
• Development in Wales, Scotland, or Northern Ireland (separate regimes apply)

For guidance tailored to smaller projects, see our article on BNG for small development projects.

How Does BNG Non-Major Development Off-Site Hierarchy Work in Practice?

For a non-major developer, the process from 6 August 2026 works as follows:

1. Commission a baseline habitat survey using the DEFRA biodiversity metric to establish the pre-development biodiversity unit value of the site [8]
2. Calculate the 10% uplift required, the number of biodiversity units that must be created or enhanced
3. Choose your delivery route, on-site, off-site registered units, or a combination. No justification is needed for choosing off-site first
4. If using off-site units, search the Biodiversity Gain Site Register (maintained by Natural England) for available registered units that match the habitat type and condition required
5. Enter a legal agreement with the off-site unit provider, secured by a conservation covenant or Section 106 agreement
6. Submit the Biodiversity Gain Plan to the local planning authority as a pre-commencement condition
7. Statutory credits are only used if registered off-site units cannot be sourced in sufficient quantity or type

The Biodiversity Gain Site Register is the central database where landowners register habitat creation sites. Units on the register are verified, legally secured for at least 30 years, and matched to specific development projects [5].

For a detailed comparison of off-site and on-site delivery options, read our guide on biodiversity net gain off-site or on-site delivery.

BNG Non-Major Development Off-Site Hierarchy vs Major Development

The single most important distinction is that the relaxed hierarchy applies only to non-major schemes. Major development retains the original sequential approach: on-site first, then off-site, then statutory credits [5].

This creates a two-tier system from 6 August 2026:

• Non-major: On-site and off-site are equal options at Step 1. Developer chooses freely.
• Major: On-site must be maximised first. Off-site is only used to top up what cannot be achieved on-site. Statutory credits remain the last resort for both.

Local planning authorities cannot impose the major development hierarchy on non-major schemes. Where advisory notes suggest on-site preference for minor sites, these are guidance only and carry no legal weight as a precondition [4].

Off-Site Units vs Statutory Credits: What Is the Difference?

These are two distinct mechanisms and the distinction matters for cost and compliance. See our detailed breakdown on the cost of biodiversity units and statutory credits.

Registered off-site biodiversity units:

• Purchased from private landowners who have registered habitat sites with Natural England
• Prices vary by habitat type, condition, and location, market-driven
• Generally more cost-effective than statutory credits for most habitat types
• Ecologically preferable because habitat is created in the real landscape

Statutory biodiversity credits:

• Purchased directly from the government via Natural England
• Fixed prices set by Defra, typically significantly higher than market off-site units
• Intended as a last resort when off-site units cannot be sourced
• Proceeds are ring-fenced for habitat creation by government bodies

"Statutory credits are not a convenient shortcut. They are priced deliberately high to incentivise genuine habitat creation through the register.", GOV.UK guidance on biodiversity net gain [5]

For non-major developers, the practical advice is: always check the Biodiversity Gain Site Register for available units before defaulting to statutory credits. The cost difference can be substantial.

When Is On-Site BNG Still the Better Strategic Choice?

Even though on-site delivery is no longer legally required as a first step for non-major schemes, there are situations where it remains the stronger option:

• Planning goodwill: Some local planning authorities look favourably on on-site biodiversity improvements, particularly in sensitive areas or where green infrastructure is a local plan priority
• Cost on larger non-major sites: If a site has genuine habitat creation potential (for example, a brownfield site with space for a wildflower meadow or sustainable drainage), on-site delivery can be cheaper than purchasing off-site units
• Green credentials: Developers targeting sustainability ratings or marketing to environmentally aware buyers may prefer visible on-site nature features
• Combination approach: Many non-major schemes will use a mix, delivering what is practical on-site and topping up with off-site units, which remains entirely valid under the new rules

For a fuller discussion of the strategic trade-offs, see our article comparing biodiversity net gain off-site or on-site delivery.

Common Mistakes With BNG Non-Major Development Off-Site Hierarchy

Confusing the hierarchy change with the small-site exemption. The 0.2 ha exemption means those schemes have no BNG obligation at all. The hierarchy change affects non-major schemes above 0.2 ha that still have a BNG obligation. These are separate instruments [3].

Assuming statutory credits are now equivalent to off-site units. Statutory credits remain the last resort. The relaxed hierarchy only equalises on-site and registered off-site units at Step 1.

Skipping the Biodiversity Gain Site Register. Some developers go straight to statutory credits because they are easier to find. This is poor practice and significantly more expensive. The register should always be checked first [5].

Ignoring habitat type matching. Off-site units must broadly match the type of habitat lost. Purchasing woodland units to offset grassland loss may not satisfy the metric correctly.

Not securing the legal agreement early enough. The Biodiversity Gain Plan must be approved before development commences. Leaving off-site unit procurement to the last minute risks delays at a pre-commencement condition stage.

BNG Non-Major Development Off-Site Hierarchy: Compliance Checklist

Use this checklist for any non-major scheme above 0.2 ha submitted or determined after 6 August 2026:

• Confirm the scheme is non-major (under 10 dwellings, under 1,000 sqm, or under 1 ha)
• Confirm the scheme is not exempt (not below 0.2 ha, not householder, not permitted development outside BNG scope)
• Complete a baseline habitat survey using the current DEFRA metric
• Calculate the biodiversity units required to achieve 10% net gain
• Decide on delivery route, on-site, off-site, or combination (no justification needed for off-site first)
• If off-site: search the Biodiversity Gain Site Register for available units
• Secure a legal agreement with the off-site unit provider
• Only use statutory credits if registered units are genuinely unavailable
• Prepare and submit the Biodiversity Gain Plan as a pre-commencement condition
• Ensure monitoring obligations are understood and documented

For further guidance, visit our guidance for developers.

FAQ

Q: Does the 6 August 2026 hierarchy change apply to planning applications already submitted before that date?
A: The change applies to applications determined after 6 August 2026. Applications already submitted but not yet determined may benefit from the new rules depending on how the local planning authority applies transitional provisions. Check with your planning consultant.

Q: Can a local planning authority still require on-site BNG first for non-major schemes?
A: No. The Biodiversity Gain (Town and Country Planning) Amendments Regulations 2026 override local policy on this point. LPAs can issue advisory notes encouraging on-site consideration, but cannot make it a legal precondition for non-major schemes [4].

Q: What is the difference between the small-site exemption and the hierarchy change?
A: The small-site exemption (for sites below 0.2 ha) removes the BNG obligation entirely. The hierarchy change affects non-major schemes above 0.2 ha that still have a mandatory BNG obligation, it changes how they can meet that obligation, not whether they have one [3].

Q: Are off-site biodiversity units always cheaper than statutory credits?
A: In most cases, yes. Statutory credits are priced by Defra at a premium to incentivise use of the register. Market off-site units are typically lower cost, though prices vary by habitat type, condition, and regional availability. See our breakdown of biodiversity unit and statutory credit costs.

Q: Does the relaxed hierarchy apply in Wales or Scotland?
A: No. The change is England-only under the Environment Act 2021 framework. Wales, Scotland, and Northern Ireland have separate biodiversity legislation.

Q: If a non-major developer wants to use a combination of on-site and off-site delivery, is that still permitted?
A: Yes, and it is often the most practical approach. The new rules allow any combination of on-site enhancement and registered off-site units. Statutory credits can top up any remaining shortfall as a last resort.

Conclusion

Two weeks into the new regime, the BNG non-major development off-site hierarchy August 2026 change is already reshaping how small developers approach biodiversity compliance. The core shift is straightforward: registered off-site units are now a valid first choice for non-major schemes, not a fallback option requiring written justification.

Actionable next steps for developers and consultants:

1. Review any live non-major applications to confirm they are using the updated hierarchy
2. Familiarise your team with the Biodiversity Gain Site Register and available unit types in your target geography
3. Build off-site unit procurement into project programmes early, do not leave it as a last-minute pre-commencement task
4. Do not conflate this change with the small-site exemption, they are separate instruments serving different purposes
5. Remember that statutory credits remain the last resort, not a convenient alternative to the register

For tailored advice on your specific scheme, visit our guidance for developers or explore the full range of biodiversity net gain resources.

References

[1] New Exemptions And Revised Thresholds For Biodiversity Net Gain From 6th August England Only – https://www.cla.org.uk/news/new-exemptions-and-revised-thresholds-for-biodiversity-net-gain-from-6th-august-england-only/

[3] Biodiversity Net Gain Changes August 2026 UK Developers Small Sites Exemption And What Changes Now – https://biodiversitysurveyors.com/blog/biodiversity-net-gain-changes-august-2026-uk-developers-small-sites-exemption-and-what-changes-now

[4] BNG Advisory Note V1.2 Accessible Version – https://blackburn-darwen.org.uk/wp-content/uploads/BNG-Advisory-Note-v1.2-Accessible-version.pdf

[5] Biodiversity Net Gain – https://www.gov.uk/guidance/biodiversity-net-gain

[6] New Biodiversity Net Gain Exemptions From August 2026 What Developers Need To Know – https://www.footanstey.com/our-insights/articles-news/new-biodiversity-net-gain-exemptions-from-august-2026-what-developers-need-to-know/

[8] Understanding Biodiversity Net Gain – https://www.gov.uk/guidance/understanding-biodiversity-net-gain

[9] Defra Revises England's Biodiversity Net Gain Regime Following Twin Consultations – https://www.osborneclarke.com/insights/defra-revises-englands-biodiversity-net-gain-regime-following-twin-consultations

[10] CIEEM Good Practice Requirements For Delivering Biodiversity Net Gain On And Off Site July 2021 – https://cieem.net/wp-content/uploads/2021/07/CIEEM-Good-Practice-Requirements-for-Delivering-Biodiversity-Net-Gain-On-and-Off-Site-July2021.pdf

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