Answer up to five questions and this checker will tell you whether the Terrorism (Protection of Premises) Act 2025 — Martyn's Law — puts you in the standard tier, the enhanced tier, the qualifying-event category, or outside the duties altogether. It takes about a minute, asks for no personal details, and explains its reasoning.
How the thresholds actually work
Most confusion about Martyn's Law comes from assuming it is purely a capacity question. It isn't — there are two separate routes into the duties, and two significant exceptions that catch people out.
The premises route. Premises wholly or mainly used for one of the uses in Schedule 1 of the Act — shops, food and drink, entertainment and leisure, sports grounds, libraries and museums, halls, visitor attractions, hotels, places of worship, health care, stations, aerodromes, childcare, schools, further and higher education, and public authority premises — are qualifying premises once it is reasonable to expect 200 or more individuals may be present at the same time. From 200 to 799 that is the standard tier; at 800 or more it is the enhanced tier.
The events route. An event can be caught in its own right, even on land that is not qualifying premises. That needs all six of the Act's conditions — including 800 or more people present at the same time, public access, and checks that attendees meet a condition of entry. Our events guide works through what that means for organisers.
The two exceptions worth knowing
Four uses are standard tier whatever their capacity. Places of worship, childcare, primary and secondary education, and further education premises are standard duty premises by reason of their use rather than their headcount. A cathedral holding two thousand people is standard tier. Note that higher education is not in that group, so a university building at 800+ can be enhanced tier.
Open-access outdoor space is excluded. Parks, gardens, recreation grounds and other open-air premises used for recreation or leisure are excluded where access is not restricted. That is why a free, unfenced village fete on the green generally sits outside the duties — though a ticketed 800+ event on the same field could be a qualifying event.
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Where to check the official position
This tool is written from the Act and the Home Office factsheets, but it is a summary and you should not rely on it alone. The primary sources are the GOV.UK factsheets — there is one specifically on assessing the number of individuals expected to be present, which is the figure everything else hangs on — the statutory guidance published on 15 April 2026, and ProtectUK, which carries free official guidance and training material. The Act received Royal Assent on 3 April 2025 with an implementation period of at least 24 months, and the Security Industry Authority is the regulator.
Common questions
Is this tool legal advice?
No. It is a plain-English orientation tool that walks you through the thresholds in the Terrorism (Protection of Premises) Act 2025 so you can see roughly where you sit. It cannot account for every circumstance, and the responsibility for determining your duties remains yours. Always confirm against the official GOV.UK factsheets and statutory guidance, and take professional advice where the risk warrants it.
How do I work out the number of people to enter?
It is the number of individuals — including staff — that it is reasonable to expect may be present at the same time, based on how the premises or event actually operates. It is not the fire capacity plaque, and not the total number of people across a whole day. The Home Office has published a factsheet specifically on assessing this figure; document whichever method you use, because that reasoning is the thing you may be asked to justify.
Why does my church or school come out as standard tier even at 800+?
Because four use types are treated as standard duty premises by reason of their use rather than their headcount: places of worship, childcare, primary and secondary education, and further education. Higher education is not in that group, so a university building at 800+ can be enhanced tier. This is one of the most commonly misunderstood parts of the Act.
My event is free and open to the public — am I really outside the duties?
Possibly, on the qualifying-event route. One of the six conditions is that the event has measures to check attendees satisfy a condition of entry — payment, a ticket or pass, membership, or being a named guest. A dress code or a suggested donation does not count. But note two things: the venue you are using may be qualifying premises in its own right with duties that affect you, and being outside the duties is not a reason to skip thinking about it.
When does this actually start being enforced?
The Act received Royal Assent on 3 April 2025 with an implementation period of at least 24 months, and the Home Office published statutory guidance on 15 April 2026. Enforcement is not expected before April 2027. Check GOV.UK, the SIA and ProtectUK for the current commencement position rather than relying on any third-party summary, including this one.
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