Martyn's Law for outdoor and street events

A festival on the common, a street party, a food market, a fireworks night, an open-air concert — none of these has a building, so Martyn’s Law judges them as an event, not as premises. And an event turns on one thing: a controlled, bounded crowd of 800 or more. Stay under that number, or leave it open for anyone to wander into, and the law does not bite. Here is when an outdoor event is caught, and what running the response on open ground actually looks like.

Does Martyn’s Law apply to an outdoor event?

Only if it is a qualifying event. A qualifying premises has to include a building, so a field, a park, a car park or a closed-off street is not caught as premises. That leaves the event test, and it is a higher bar than the one for premises: an outdoor event is in scope only if it is open to the public, expects 800 or more people at the same time, and controls who gets in behind a well-defined, secure perimeter.

So the threshold outdoors is 800, not the 200 that applies to a building. And all of those conditions have to be true together — miss one and it is not a qualifying event, whatever the headcount.

The boundary is what decides it

This is the part that matters most outdoors. With no walls, the perimeter you put up is the premises for the day. A fenced, ticketed music festival expecting thousands has a boundary and an entry check — it is in. A free, open gathering anyone can walk into — a parade, a switch-on in the square, a free festival on the park — has neither, so it is not a qualifying event, however big the crowd.

That is not a loophole to lean on; it is the logic of the law. If you cannot say where your event starts and stops, and you are not checking who comes in, you could not run a controlled evacuation or hold a perimeter anyway. The boundary is what makes a response possible — which is why the law hangs the duty on it.

What counts as controlling entry?

A real check that someone is entitled to be there: they have paid, hold a ticket or pass, or are a member or guest. The check can be a person on the gate or automatic — wristbands, barcodes, a box office — as long as there is a secure perimeter so it actually means something. A free event can still qualify if it has an entry check of this kind.

What does not count: a bag search on the way in, a dress code, or a suggested donation. Those manage the crowd or raise money; they do not decide who is allowed through the gate.

Who is responsible?

Whoever controls the event — the organiser running it and controlling the ground it uses. If you put your event on council land, it is usually you, the organiser, not the council that owns the park — unless the council is the one running it. Where a landowner or a venue with its own duty is also involved, the Act expects you to co-ordinate, so far as is reasonably practicable, rather than each assume the other has it covered.

What would you actually do — with no building?

The same four procedures as anywhere else, worked out for open ground. Because a qualifying event is a crowd of 800 or more, it sits at the heavier end — the Enhanced Tier style duties: procedures and measures, with a documented assessment of how they reduce the risk. For the four procedures, on a field that means:

• Evacuation — getting people out through the gates and exits to a rendezvous well away from the site, and who gives the word. On the day that is your stewards acting on one clear instruction.
• Invacuation — moving people to a safer part of the site if the danger is outside it. Outdoors this can be the opposite of a fire drill: sometimes holding people inside a secure perimeter is safer than pushing them out into an open street.
• Lockdown — controlling the perimeter: closing the gates, holding the line and stopping someone getting in, and who has the authority to call it.
• Communication — reaching a field of people quickly: a PA, the stage screens, and stewards on radio, so one instruction lands across the whole site.

Alongside the procedures, a qualifying event also has to put public protection measures in place, so far as is reasonably practicable, and keep a short assessment of how they cut the risk. The Act groups them four ways — on open ground that means:

• Monitoring — eyes on the event and its approaches: a steward rota, a control point, and CCTV if you have it.
• Movement of people — how the crowd flows in, around and out: entry lanes, clear routes, and no bottlenecks at the gates.
• Physical safety and security — the fencing and barriers that make the perimeter real, queue management, and something to stop a vehicle where one could reach the crowd.
• Security of information — not publishing what would help someone plan an attack: detailed site layouts, timings, and your security arrangements.

The people who deliver all of that are your stewards. The job is to make sure they know the plan, know who calls it, and could carry it out on the day — not just that it is written in a file somewhere.

Draw the site, not just describe it

Because it is open ground, a plan of the site earns its place even more than it does in a building. Mark the perimeter, the gates and exits, the rendezvous points and the corners a shout or a PA will not reach. It is the fastest way to see the gaps before the day — our guide on drawing your response on the plan walks through it, and the core event rules are in what counts as a qualifying event.

You have time to get this right

Martyn’s Law is not in force yet. The statutory guidance was published on 15 April 2026, and the government has committed to a minimum 24-month implementation period before the duties apply — so, with Royal Assent on 3 April 2025, April 2027 is the earliest they could come into force. The regulator’s notification system is not open yet either, so there is nothing to file today. For a recurring event, that is time to build the perimeter, the gates and the rendezvous into how you run it — once — rather than scrambling against a deadline.

Where the definitive answer is

For definitive information about whether your premises or event is within scope and what is required, refer to the current statutory guidance issued under the Terrorism (Protection of Premises) Act 2025.