6 min read | May 17, 2024

What Developments are Exempt from BNG?

The list of exemptions for the UK’s new Biodiversity Net Gain mandate are narrow and very (and we mean very) specific, they have been laid out to ensure that BNG does not inhibit very small scale developments. The key thing to note about exemptions is that they are designed to be the exception, not the rule. By definition, exemptions are designed to be few and far between. In this blog, we’ll brief and exemplify exactly what developments are exempt. 
Taking The Scenic Routeby v2osk

The BNG De Minus Exemption 

The de minimis exemption is designed for the very smallest planning applications. In the words of the Government, it was designed with street furniture in mind - think benches and disability ramps. 

Specifically, the exemption applies to developments that 1) don’t “impact” priority habitats, AND 2) “impact” less than 25 square metres of non-priority onsite habitat, AND 3) “impact” less than 5 metres for non-priority linear habitats. All three of these requirements must be met in order to be exempt. 

Why the quote marks? Because “impact” is defined in the law as meaning a negative impact as measured by the metric itself. Note that this applies to non-zero rated habitats (so not surfaces like tarmac or buildings, already in place). 

It’s worth noting that this is a tricky exemption to claim. Why? Because there are many grounds that will mean that the exemption won’t be appropriate. Just because there isn’t clear vegetation on a site that doesn’t mean that there site is eligible for a de minimis exemption. You should also be aware that the presence of trees on or near the site may mean that the de minimis exemption isn’t appropriate if any of these trees are impacted. 

A good example of a de minus exemption would be an accessibility ramp to a building entrance that is already on an established hardstanding or developed area. This addition wouldn't disrupt or change any existing habitats, and falls in line with other compliance mandates within the UK. 

Developers can consult publicly available datasets on priority habitats to determine whether their site falls under this exemption.

Householder Developments

This exemption applies to modifications or extensions to existing houses. If it is a householder application then your development is automatically exempt. 

Biodiversity Gain Sites

Exemptions are applied to off-site biodiversity gain projects in the cases where enhancements would require an additional 10% net gain. To prevent this redundancy, the following types of site developments are exempt:

“developments which solely enhance biodiversity to achieve the BNG planning condition for another development through off site enhancements of habitat.


development undertaken to fulfil the BNG planning condition and for the purpose of permitting the public to access or to use the site for educational or recreational purposes without the payment of a fee.”

Small Scale Self-Build and Custom Housebuilding

Exemptions also apply to self and custom build developments consisting of no more than 9 dwellings on sites no larger than 0.5 hectares. All houses must meet the legal definition of self-build or custom builds - this is a very specific definition and can’t be generally claimed. 

High Speed Railway Transport Network

This exemption covers development associated with the remaining phases of the high-speed transport network.

Implications and Considerations

While these exemptions exist, applicants should remember that BNG is a general condition for planning permission. Exemptions are meant to be the norm and - even if a exemption is allowed - it will likely always be possible to do BNG. All developers should consider the possibility of BNG whenever they submit a planning application, regardles of exemptions.

You can quickly and affordably check if your development is exempt with Joe’s Blooms BNG Exemption Checker. If you are, the tool will provide you with the legal documents that prove your BNG exemption.

Oliver Lewis

Oliver Lewis

Founder of Joe’s Blooms
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Oliver Lewis is the founder of Joe’s Blooms, providing end-to-end digital solutions to help you create best-in-class Biodiversity Gain Plans. Expert in this field, he shares his knowledge on the Environment Bill.

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