A plain-English scope check for Martyn's Law.
Martyn's Law Check reads a few facts about your premises or event and tells you whether the Terrorism (Protection of Premises) Act 2025 applies to you, which tier you are in, and the duties that follow. It is a scoping tool for operators who need a clear answer, not a law firm.
What it is
Martyn's Law is named after Martyn Hett, one of the 22 people killed in the Manchester Arena attack in 2017. The Terrorism (Protection of Premises) Act 2025 received Royal Assent on 3 April 2025. It asks those responsible for certain premises and events to be better prepared for a terrorist attack and to reduce the harm one could cause.
Plenty of free material exists on gov.uk and ProtectUK. What is harder is getting a clear answer for your specific site: does this catch you, which tier are you in, and what must you actually do. This tool takes the handful of facts that decide that, your use, your capacity band and your role, and returns a verdict, your itemised duties and a checklist you can act on.
How the verdict is reached
The tiers and thresholds are set out in the Act and the Home Office statutory guidance. A qualifying premises with a Schedule 1 use and 200 to 799 people reasonably expected at the same time is standard tier; 800 or more is enhanced tier; a qualifying event of 800 or more with controlled access is enhanced tier. Under 200 is out of scope on capacity. The free check and the report apply exactly those rules. Our methodology sets out each step, and our sources page lists the primary references.
Independence
Martyn's Law Check is an independent, privately operated tool. It is not affiliated with, authorised by, or endorsed by the Home Office, the Security Industry Authority (the regulator), or any authority. We cite the Act and the Home Office guidance so you can read the source yourself.
A note on timing
The Act is not yet in force. The Home Office has committed to an implementation period of at least 24 months from Royal Assent, and commencement is expected around spring 2027, though the exact date is not yet fixed. Nothing here is a live legal duty yet. We date every fact and flag the status so you are preparing against the right timeline, not a false deadline.