How many people does my building need to count towards Martyn's Law?
In short
Martyn's Law asks how many people you actually, realistically expect at your busiest times — not the maximum number your building could technically hold for fire safety purposes. Those two figures are often very different, and using the wrong one can tip you into a duty the law doesn't place on you, or hide one that it does.
Key points
The test is the number reasonably expected at the same time, from time to time — not an average, and not a theoretical maximum.
Staff, volunteers and contractors must be included in the figure, not just visitors or ticket-holders.
A safe occupancy figure for fire safety is one accepted way to estimate the number, but where your actual attendance is reliably lower, the lower figure is what counts.
A group of buildings adds its figures together; a smaller unit inside a larger site does not add the whole site's figure to its own.
You'll need to say which method you used to reach your number, and show your working, when you eventually notify the SIA.
"From time to time", not an average
The Act's wording is specific: it asks whether it's reasonable to expect 200 (or 800) or more people present at the same time "from time to time". The government's own supplementary guidance is explicit that this doesn't mean an average over a day, a week or a season — a hall that's usually at 40 but reliably hits 220 every Christmas fair is assessed on the 220, because that's genuinely, predictably reached, even though it isn't typical. Equally, a one-off that happened once and isn't expected to happen again doesn't count at all, in either direction — it doesn't bring an otherwise small premises into scope, and it doesn't push an in-scope premises up a tier.
Count everyone connected with the activity — including yourselves
It's easy to count the audience and forget the people running the event. The figure must include everyone present in connection with the premises' use, which expressly includes staff, volunteers and contractors, however they're employed or engaged. A hall that sells 195 tickets but has five committee members on the door, in the kitchen and behind the bar is actually expecting 200, not 195 — and 200 is the threshold. If the way you worked out your number didn't already include your own people — ticket sales and seating counts often don't — you need to add them on top, not assume they're covered.
Why a fire safety figure can mislead you
One recognised way of estimating your number is to use the safe occupancy figure calculated for fire safety purposes — the number your building could hold under separate fire safety rules. It's a legitimate starting point, but it answers a different question: fire safety asks how many could safely escape, not how many you actually expect. The government's own worked example makes the point directly: a gallery with a safe occupancy figure of 850 for fire safety, but historic records showing it reliably peaks at 500, is treated as standard tier on the 500 — not enhanced tier on the 850. Whatever method you use must be a reasonable, evidenced assessment of your own expected attendance, and where good records show a lower figure than your fire capacity, that lower figure is the one that counts.
If your premises is more than one building used together — a church and its hall, say — add the expected number in each building together for your total. But if you're a smaller part of somebody else's site, such as a café inside a leisure centre, you count your own expected number only; you don't add in the whole site's figure, which is someone else's assessment to make.
Needs a closer look
Where your figures depend on someone else's premises — a unit inside a larger site run by the same organisation as you — the Act may treat you as one combined premises rather than two separate ones. That changes the number the thresholds apply to, and it needs a closer look rather than a guess. Check your scope to work through it properly.
Common questions
- Do we count people who are in the building but have nothing to do with our event?
No — only those present in connection with your premises' use. If you're a shop inside a much bigger building used for something else entirely, you don't count the rest of the building's visitors, only your own.
- Our safe occupancy certificate says we can hold 300 — is that our number?
Not necessarily. That's a reasonable starting point, but if your actual, reliable attendance is lower, the lower figure is the honest and evidenced one to use.
- What if we've never properly counted before?
Use whichever reasonable method fits how you operate — a seat count, ticket sales, past attendance records or a licensed capacity limit — and write down how you reached your figure, including whether staff and volunteers were already in it. Check your scope if you're not sure which applies.
Check your building, free
Answer a few questions about who uses your building and how many people could be there at once. We’ll tell you plainly whether Martyn’s Law applies, and why.
Sources
Last reviewed 2 November 2026, against the statutory guidance of 15 April 2026 (corrected 6 August 2026).