Check whether a venue or an event falls under the Terrorism (Protection of Premises) Act 2025, which tier it sits in, who is responsible, and what the Act will require. It is the UK law often called Martyn’s Law. Everything you type stays in this browser.
1The site
What it is and what it is used for.
Why this matters
The main use decides whether a tier override applies, and in some cases who is responsible. For sites with more than one use, the Principal Use of Premises Regulations 2026 (in force from 15 October 2026) say it is the use that “relates most closely to the purpose and nature of the premises”. The factors are how the site was built or modified, whether it is still used that way, its physical layout, and how the local authority treats it. Write down why you chose it.
2The count
The most people likely to be there at once, staff included. Count only people there for the public use: a factory floor behind a shop doesn’t count towards the shop.
Busiest normal period
Peak, not average.Biggest regular occasion
The largest occasion that happens every year or more often, or is planned to happen again.The one-off occasion
About the methods
The Act gives no method for counting. The Home Office lists six in a supplementary document, which is guidance rather than law. They can give different figures for the same site and nothing says which one wins. Use the one that best reflects real peak use. A fire or licence capacity is a ceiling: where your recorded peak is reliably lower, the guidance uses the recorded peak.
Staff means employees, contractors, volunteers and anyone else working there for the public use. Giving the SIA false or misleading information is a criminal offence, so the method you declare should be one you can evidence.
3The answer
Position
Start with the site
Not sure about any of this?
A tribunal can settle every question this tool answers: whether a site or event is covered, its tier, its main use, and who is responsible. The SIA, or anyone with any control of the site, can apply (section 11).
4Who is responsible
Whoever controls the site for its public use. Owning the building or holding the licence doesn’t settle it.
The tenanted pub correction
In April 2026 the guidance said a brewery holding the licence for a tenanted pub was responsible. On 6 August 2026 the Home Office corrected it: the tenant controls the pub, so the tenant is responsible. Material written between those dates may still carry the error.
5The next 60 days
6What the Act requires
Alongside your other duties
The Act sits alongside the law you already work to, and doesn’t override it. These are the places they meet. Only you can settle them for your site, so record what you decide and why.