Martyn’s Law: what it means and how to get communication right

Martyn’s Law — formally the Terrorism (Protection of Premises) Act 2025 — requires certain UK premises and events to be prepared to keep people safe in the event of a terrorist attack. It received Royal Assent on 3 April 2025 and is expected to come into force after an implementation period of at least 24 months, around 2027. The Home Office published its statutory guidance in April 2026. The law is named after Martyn Hett, one of the 22 people killed in the 2017 Manchester Arena attack, and was driven by the campaign led by his mother, Figen Murray.

For the first time, those responsible for many public venues and events will be legally required to plan how they protect people — and communication sits at the heart of that. Of the four core “public protection procedures” the law sets out — evacuation, invacuation, lockdown and communication — communication is the thread that makes the other three work. Not forcing, but steering smarter.

Who Martyn’s Law applies to

The law applies across England, Wales, Scotland and Northern Ireland, and splits in-scope premises and events into two tiers based on how many people are reasonably expected to be present at the same time:

• Standard tier (200–799 people) — must put in place public protection procedures (evacuation, invacuation, lockdown and communication). The emphasis is on planning and readiness; there is no requirement to document them or install physical measures. In short: think and plan.
• Enhanced tier (800 or more people) — must do all of the above and put in place public protection measures covering monitoring, movement, physical security and information security. They must also document their compliance, submit it to the Security Industry Authority (SIA), designate a senior individual and keep their measures under review. In short: build and prove.

Public events are in scope from a capacity of 800 or more. Some premises — such as schools and places of worship — fall under the standard tier regardless of capacity. The penalties for enhanced-tier breaches are significant: up to £18 million or 5% of qualifying worldwide revenue, whichever is greater, plus daily penalties for ongoing contraventions.

The four procedures — and why communication ties them together

Martyn’s Law defines four core public protection procedures:

• Evacuation — moving people safely out of the premises.
• Invacuation — moving people to a safer area inside the premises.
• Lockdown — securing the premises and restricting access.
• Communication — getting clear, reliable messages to staff and the public quickly.

Each of the first three depends on the fourth. You cannot evacuate, invacuate or lock down a crowd you cannot reach. The statutory guidance is explicit that organisations should check whether their communication methods are fast, clear and reliable. That is exactly the problem we solve.

Where CrowdCows fits — the communication layer

To be clear: meeting Martyn’s Law is broader than communication alone. Risk assessment, procedures, training and — for enhanced premises — physical measures are for you and your security advisers, and nothing on this page is legal advice. What we do is the communication layer, at the scale and reliability these situations demand.

We place our HIKER screens — robust LED screens on a concrete base — at tactical points across a site, route or venue, and drive each one individually and wirelessly from a single control room. The system is built for situations where mistakes have major consequences: redundant, vandal-resistant and equipped with backup power, so communication keeps working even if technology fails. In an emergency, safety messages automatically override all other content. And because a screen that shows information is not the same as a screen that changes behaviour, we apply behavioural-psychology techniques so messages actually land. Whether you need to steer a crowd along a safe route, hold people in place, or push an emergency instruction in seconds, our system is built for exactly the moments Martyn’s Law asks you to prepare for.

Proven where it matters most

This is not theory. At Notting Hill Carnival — one of the most demanding crowd environments in the UK — we ran 14 HIKER screens from the Control Room to steer up to two million visitors, and the Metropolitan Police’s Carnival commander pointed to the screens on the BBC. At the British Grand Prix at Silverstone, we guided the exit of a vast motorsport crowd with screens and dynamic signage, controlled live from the Event Control Centre. The same approach underpins our wider crowd communication work across Europe’s largest events.

More about Martyn’s Law and communication

This page is general information about Martyn’s Law and is not legal advice. For your specific obligations, refer to the Home Office statutory guidance or a qualified adviser.