Regulation 10(5)(a): International relations, defence, national security and public safety

When disclosure of environmental information would substantially prejudice international relations, defence, national security or public safety.

International relations, defence, national security and public safety#

Regulation 10(5)(a) of the EIR(S) allows an authority to refuse your request if disclosure would, or would be likely to, substantially prejudice international relations, defence, national security or public safety. This is the broadest of the substantial prejudice exceptions, covering four distinct interests in a single provision.

In plain terms#

The authority is saying that releasing the information would cause serious harm to one of these four interests. In an environmental context, this might involve plans for critical infrastructure like water treatment works, information touching on military land use, or environmental data shared in confidence between governments.

You ask a council for the site-specific fire and incident plan for a fuel storage depot near your home. The council withholds details about on-site fuel capacity, fire-fighting resources, and access points, arguing that this information could be used to target the depot. The authority relies on the “public safety” limb of regulation 10(5)(a).

The legal detail#

Regulation 10(5)(a) applies where disclosure would, or would be likely to, substantially prejudice one or more of:

international relations - the UK’s relationships with other states and international organisations
defence - the defence of the realm, armed forces operations, military planning
national security - the security of the United Kingdom and its people
public safety - the welfare and protection of the general public from danger, harm, or injury

None of these terms is defined in the EIR(S). The Aarhus Convention Implementation Guide says they should be given their generally accepted meaning in international law.

This is a substantial prejudice exception. The authority must show that disclosure would cause real and significant harm - not just theoretical risk or diplomatic awkwardness. There must be a genuine, demonstrable link between releasing the information and the harm claimed. The Commissioner has rejected claims based on speculative or hypothetical risks.

The public interest test#

Even where the authority establishes substantial prejudice, it must apply the public interest test under regulation 10(1)(b). The presumption favours disclosure. Environmental information about pollution, contamination, or public health risks may tip the balance towards release even where national security or public safety concerns exist.

See What can they refuse? for how the public interest test works under the EIR(S).

How it’s used in practice#

The Commissioner has dealt with this exception across all four limbs. In Decision 051/2009, Scottish Ministers withheld correspondence about the proposed introduction of Giant Pandas to Edinburgh Zoo, arguing that disclosure would harm relations between the UK and China. The Commissioner accepted this, noting the sensitivity of the diplomatic context and that the information included views expressed with candour by both UK and Chinese officials.

In Decision 080/2019, North Ayrshire Council withheld building warrant details relating to Hunterston nuclear power station. The Commissioner was satisfied that some of the information would substantially prejudice national security, but ordered disclosure of other parts.

Public safety claims face particular scrutiny. In Decisions 102/2015 and 103/2015, Scottish Ministers withheld information about seals shot at salmon farms, arguing that disclosure would endanger staff safety by provoking protest action. The Commissioner rejected this - the Ministers had not provided evidence of a genuine and realistic threat to public safety or shown that harm was likely in the near future.

By contrast, in Decision 033/2015, Historic Scotland successfully withheld details about the refurbishment of the First Minister’s official residence. The Commissioner accepted that the detailed plans would provide information about entry points and surveillance vulnerabilities, creating a real risk to the security of the First Minister, Cabinet, and staff.

How to challenge it#

Ask which limb they’re relying on. International relations, defence, national security, and public safety are different interests. The refusal letter should specify which applies and explain why disclosure would cause substantial prejudice to that particular interest.

Challenge vague claims. The authority must show specific, real harm - not just that the information “relates to” defence or security. The fact that information concerns a sensitive subject does not automatically mean disclosing it would cause substantial prejudice.

Check whether the information is already public. If similar information has been officially published elsewhere, the authority will struggle to show that disclosure under the EIR(S) would cause additional harm.

Argue the public interest. Even if the exception applies, the public interest may favour disclosure - particularly where environmental contamination or public health is at stake.

See What to do if refused for the full process.

You can also use our interactive challenge tool for this exception to work through these questions step by step and draft a review request.

Good to know: This is the only EIR(S) exception where a ministerial certificate is available. Under regulation 12(1), Scottish Ministers can certify that disclosing the information would substantially prejudice national security. If issued, the certificate prevents the Commissioner from questioning whether the harm would occur - but it does not override the public interest test. No certificate has ever been issued. This exception also carries a neither confirm nor deny (NCND) power under regulation 10(8). The authority can refuse to reveal whether it holds the information at all, provided doing so would itself cause substantial prejudice to one of the 10(5)(a) interests and it would not be in the public interest to confirm or deny. The emissions carve-out in regulation 10(6) does not apply to this exception - it can be used even where the information relates to emissions. Under FOISA, the nearest equivalents are section 31 (national security and defence) and section 32 (international relations).