Biodiversity Net Gain Changes - Effective from 6th August 2026
- 5 hours ago
- 4 min read
Biodiversity Net Gain (BNG) rules for developments in England are changing from 6th August 2026. This blog post explores what the changes are, what will stay the same and what this may mean for your development and planning application.
What Are The Changes?
Planning applications for Sites with a red line boundary of less than 0.2 hectares and do not impact any Priority Habitats on Site will be exempt from the biodiversity gain planning condition requiring a minimum of 10% BNG to be delivered.
Planning applications which solely constitute a temporary development lasting no longer than 5 years and do not impact any Priority Habitats on Site will be exempt from the biodiversity net gain planning condition.
Changes to the Biodiversity Gain Hierarchy - minor developments will now be able to opt for purchasing registered offsite biodiversity units (such as those listed on the Biodiversity Gain Register) in lieu of delivering BNG on site through habitat creation and enhancement.
The BNG exemption for developments proposing 9 or fewer dwellings on a Site no larger than 0.5 hectares and consisting solely of self-build or custom housing will no longer exist.
What Is Staying The Same?
The 'de minimus' exemption from the biodiversity gain planning condition will still exist, i.e. development that does not impact a Priority Habitat and impacts less than 25 square metres of onsite habitat or less than 5 metres of linear habitat such as a hedgerow.
Householder developments will still be exempt from the biodiversity gain planning condition.
Urgent crown development, developments to deliver biodiversity gain sites and developments related to the high speed railway transport network will still be exempt from the biodiversity gain planning condition.
The purchase of Statutory Biodiversity Credits will still be a last resort for minor and major developments. In addition, the need for both minor and major developments to avoid and minimise impacts to medium, high and very high distinctiveness habitats before seeking to enhance, create or purchase offsite biodiversity units to achieve a minimum of 10% BNG will still apply.
What Will This Mean For Development?
The above changes to BNG rules will only apply for planning applications lodged on or after 6th August 2026.
The above changes to BNG rules will not apply to variations of planning applications granted before 6th August 2026.
An ecology survey is still likely to be required to confirm whether Priority Habitats are present on Site and if they will be impacted by the proposed development. 'Impacted' can either mean the habitat, or part of the habitat, will be lost, or, the habitat will be negatively affected in such a way that its value within the Statutory Biodiversity Metric is decreased, for example, an area of good condition grassland may be made into poor condition grassland due to proposed grassland management or a proposed change in land use.
The proposed changes to the Biodiversity Mitigation Hierarchy will make it easier for minor developments not covered by the 0.2 hectare exemption to achieve the minimum 10% BNG. Minor developments will be able to choose to purchase offsite biodiversity units to achieve 10% BNG, reducing the pressure to deliver potentially unrealistic high value habitats on site.
The New Biodiversity Gain Hierarchy
The changes to the Biodiversity Gain Hierarchy in article 37A of the Town and Country Planning (Development Management Procedure) (England) Order 2015 will in effect, create two different orders of priority for achieving BNG, one for minor developments and one for major developments.
Both minor and major developments will still be required to first avoid effects to medium, high and very high distinctiveness habitats (such as the majority of woodland types, native hedgerows with trees and individual trees).
Once this avoidance and mitigation has been put in place, major developments must then achieve BNG in the following order of priority: habitat enhancement on Site, habitat creation on Site, purchase of registered offsite biodiversity units and finally as a last resort, purchase statutory biodiversity credits.
For minor developments, once avoidance and mitigation for medium distinctiveness and above habitats has been put in place, BNG can then be achieved by either: habitat enhancement on Site, habitat creation on Site or through the purchase of registered offsite biodiversity units. Should these options still not deliver the minimum 10% BNG, the purchase of statutory biodiversity credits can be considered as a last resort.
Put side by side, the changes to the Biodiversity Gain Hierarchy on 6th August 2026 will look as follows.
What Further BNG Changes Are On The Horizon?
DEFRA's BNG update on 20th April 2026 states that the following further changes to BNG rules are on the horizon for later in 2026:
Introduce an exemption for development whose primary objective is to conserve or enhance biodiversity.
Introduce a targeted exemption for development that enhances parks, playing fields and public gardens.
Adjust the way spatial risk is assessed for area habitats, using Local Nature Recovery Strategy areas only.
Improve identification of Open Mosaic Habitat and other urban habitats by updating Metric guidance.
Introduce the use of a proxy habitat as an acceptable alternative when no Open Mosaic Habitat units are available.
Move the current Excel Metric tools to a digital, integrated service.
Consider changes to the assessment of watercourse condition, including a new distinctiveness category for highly modified watercourses.
Further Guidance
If you are a land owner or developer and would like further advice and guidance on Biodiversity Net Gain, contact Autumnwood Arboriculture and Ecology Ltd. at info@autumnwoodconsultancy.co.uk and we would be happy to assist with your enquiry.
Article References
Comments