The short answer
Martyn's Law — the Terrorism (Protection of Premises) Act 2025 — requires certain venues and events to prepare for a terrorist attack. Premises where 200 to 799 people may be present fall into the standard tier, which focuses on simple procedures to protect people; those for 800 or more fall into the enhanced tier, with further measures and documentation. It is regulated by the Security Industry Authority, with an implementation period before the duties apply.
Why it exists
The Act is named after Martyn Hett, one of the 22 people killed in the Manchester Arena attack in 2017. His mother, Figen Murray, campaigned for venues to have a legal duty to plan for terrorism, as they already do for fire.
Standard tier: 200–799 people
The standard tier is about procedures, not expensive equipment. In outline, it asks those responsible to be ready to act quickly: how to evacuate, how to move people to safety inside, how to lock down, and how to communicate with people on site — and to make sure staff know what to do.
Enhanced tier: 800 or more
Larger premises and qualifying events must go further: measures to reduce vulnerability to an attack and the harm it could cause, such as monitoring and controlling who comes in, plus documented plans and a designated senior individual.
How to prepare now
- Work out which tier your premises or events are likely to fall into.
- Write down simple procedures for evacuation, invacuation and lockdown, and walk them through with staff.
- Make sure staff know how to spot and report something that does not feel right — the government’s free ACT (Action Counters Terrorism) awareness training is a good start.
- Review how people get in: searching, entry control and CCTV coverage at the points where crowds gather.
- Follow the SIA’s guidance as it is published — it is the regulator, and the detail matters.
Where we help
Licensed, briefed event security for entry control and searching, monitored CCTV with operators watching live, and incident management planning for the day the plan is needed. This guide is general information, not legal advice.
Talk it through with us
Every site is different. Tell us about yours and we will tell you plainly what we would do.