Evacuation, invacuation, lockdown, communication: the four procedures
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Martyn's Law's standard-tier duty comes down to four types of public protection procedure: evacuation, invacuation, lockdown and communication. Each has a distinct purpose, and a venue's job is to work out, in plain terms, what each one would actually look like on its own premises. Here's what the guidance says about each, with a worked example for a different kind of venue.
Evacuation
Evacuation means getting people out of the premises and away from danger.
The guidance's considerations include: which exits are usable, whether some should be avoided depending on where the threat is, who directs people, and where they should gather once outside, away from the building rather than clustered by the entrance.
Worked example: a gym. A leisure centre with a main entrance, a rear fire exit by the changing rooms, and a car park at the front. Its evacuation procedure names the rear exit as the default route if the threat is at the front, sends the duty manager to sweep the changing rooms and pool area last, since people there are less likely to have heard an announcement, and directs everyone to gather at the far end of the adjoining playing field, not the car park, which is too close to the building and the road.
Common mistake: writing an evacuation procedure that assumes the threat is always inside the building, so it always sends people toward the nearest exit, without considering that the nearest exit might be walking people straight toward danger outside.
Invacuation
Invacuation means moving people to a safer place inside the building, or bringing them in from outside, when the danger is outside rather than in.
The guidance's considerations include: how you'd get outdoor areas cleared and secured quickly, which internal doors or gates can be locked, and how you'd account for people who might not hear or understand an instruction to come inside.
Worked example: a pub. A pub with a busy beer garden opening onto a side street. Its invacuation procedure has bar staff nearest the garden doors bring customers inside immediately on the signal, rather than waiting for people to finish their drinks, and the duty manager locks the garden gate from inside once it's clear, so nobody can be pulled back out or wander back in unaware.
Common mistake: having no invacuation procedure at all, on the assumption that "evacuation" covers every scenario. A venue with any outdoor or semi-open space needs a plan for bringing people in, not just sending them out.
Lockdown
Lockdown means securing the premises to keep danger out, distinct from invacuation's job of getting people to safety once they're already inside.
The guidance's considerations include: which doors can actually be locked from the inside, where keys or fobs are kept, whether any doors release automatically on a fire alarm in a way that would defeat a lockdown, and who has the authority to call it.
Worked example: a church. A church running a well-attended Sunday service. Its lockdown procedure has whoever is on welcome duty at the main doors lock them from inside on the signal, notes that a side vestry door also needs securing since it's often left propped open for deliveries, and confirms that neither door is on an automatic fire-alarm release, since that would undo the lockdown the moment an alarm sounded.
Common mistake: assuming a door is secure because it has a lock, without checking whether it's wired to release automatically on a fire alarm, which some fire safety systems do by design.
Communication
Communication means alerting everyone present quickly and telling them what to do, in a way that's actually understood.
The guidance's considerations include: what words are used, who says them, over what system, and making sure the message is specific enough to act on rather than a vague or unexplained alarm that leaves people guessing.
Worked example: a village hall. A volunteer-run hall regularly hired out to outside groups it doesn't otherwise staff. Its communication procedure gives whichever committee member or hirer is present a short, fixed phrase to use ("please move to the car park now, this way"), repeated twice, rather than relying on an alarm the hall doesn't have, and includes a line in every hire agreement telling hirers where that phrase and the rest of the procedures are kept.
Common mistake: an announcement that's technically audible but not specific, "there's an incident, please be aware", that leaves people unsure whether to move, and if so, where.
How the four interact
A single incident can call for more than one procedure in sequence: communication to alert people, then evacuation or invacuation depending on where the danger is, with lockdown following once everyone who's coming in is in. Decide in advance who has the authority to call each one, so nobody is waiting for permission mid-incident.
Fire procedures are not enough on their own
Your existing fire evacuation plan is not a substitute for these four. A fire procedure assumes the danger is the fire itself and sends everyone to the nearest safe exit and a fixed assembly point; a terrorism incident might mean the nearest exit or the assembly point is exactly where you shouldn't be. Keep both plans, and think through where they'd genuinely differ for your building, rather than assuming one covers the other.
"Reasonably practicable" is a proportionality test, not a minimum bar
Procedures have to be appropriate and reasonably practicable for your premises, weighing what achieves the objective against the cost, time and difficulty of doing it. That cuts toward simplicity as often as it cuts toward more effort: the guidance's own example is a venue that wrote several different evacuation procedures for different attack types, watched staff freeze during a practice because they couldn't tell which one applied, and replaced them all with one clear procedure. More complexity is not automatically more compliant.
Writing it down and briefing staff
None of this has to be a formal document by law, but writing your four procedures down is how you brief staff consistently and how you'd demonstrate compliance if an inspector asked. See a free template to get started, and our guide to training for how to make sure the people who need to know their role actually do.
Start with the free checker to confirm your tier, or see the standard tier explained for how these four procedures fit into the wider duty.
Common questions
What is invacuation?
Invacuation means moving people to a safer place inside the building, or bringing them in from outside, rather than getting them out. It's the opposite instinct to a fire evacuation, and it's often the right response when the danger is outside, for example in the street or a car park, rather than inside the premises.
Do I need all four procedures?
The Act asks for procedures appropriate to your premises, not a fixed checklist you must tick regardless of relevance. In practice, most venues with an inside and an outside space, a beer garden, a car park, a hired room, need all four in some form, because the danger could plausibly come from any direction. If a genuine reason means one clearly doesn't apply to your building, note why, rather than skipping it silently.
Who decides which procedure to trigger during an incident?
That's a decision you make in advance, not in the moment. Name who has the authority to call evacuation, invacuation or lockdown at your venue, usually the duty manager or most senior person on shift, so staff aren't left waiting for someone to figure out who's in charge.
About this guide. Written by the Martyn's Law Plan team, based on the statutory guidance published under the Terrorism (Protection of Premises) Act 2025. Last reviewed: . Read the official guidance on GOV.UK.
Sources: Terrorism (Protection of Premises) Act 2025; Home Office statutory guidance (April 2026, updated May 2026) and supplementary documents. Paragraph references are to the statutory guidance. General information, not legal advice. Contains public sector information licensed under the Open Government Licence v3.0.