More than one use? The principal-use test explained
Last reviewed:
Plenty of real buildings don't fit neatly into one of the Act's 17 listed uses. A shop with a flat above it, a leisure centre inside a council office building, a shopping centre with dozens of separately let units. The Act handles this with a principal-use test, and a part-of-building rule that lets one use qualify even where the rest of the building doesn't.
The principal-use test
Where premises are used for more than one purpose, the Act asks what the principal use is, and applies the Schedule 1 test to that (para 4.18). "Principal" means the main, dominant use of the premises, not simply the largest use by floor area, and not every incidental or occasional use counts. A small staff kitchen inside a shop doesn't turn the shop into a mixed-use premises; a genuinely separate business or activity operating alongside the main one is a different question. Where it's not obvious, look at what the premises are actually held out and used for, day to day, rather than picking whichever label is administratively convenient.
Part of a building can qualify on its own
You don't need the whole building to be a Schedule 1 use for part of it to be in scope. The guidance's own example is a factory with a shop attached: the factory floor itself isn't a Schedule 1 use, but the shop part can still qualify on its own if it separately meets the public-access and numbers tests (para 4.8). The same logic runs the other way for many everyday buildings: a restaurant with a flat above it doesn't pull the private flat into scope, and a leisure centre operating inside a larger council building can be assessed on its own terms rather than by reference to the whole building's mix of uses.
Groups of buildings can be one premises, or many
The same principle scales up. A group of buildings under common control can be treated as a single premises, the guidance's own example is a hospital trust running 14 buildings across one site, assessed together rather than building by building (para 4.9). But common ownership alone doesn't force that outcome: a supermarket chain with stores across the country is a different pattern, and the guidance's own example has each store counted separately, not summed nationally, because each store is independently controlled and used on a day-to-day basis rather than functioning as one combined premises.
Nested premises: the shopping-centre example
Shopping centres are the clearest official illustration of how nesting works. The centre operator is the responsible person for the centre as a whole, common areas, mall walkways, shared entrances, and the centre's own total can be built up by summing the individually let units. Each unit is separately assessed too, with its own occupier as the responsible person for that unit specifically. Crucially, a unit's own total isn't inherited from the centre, and the centre's total isn't simply the sum of what each unit would be on its own; they're related but separately assessed figures (para 4.30). The same nested pattern shows up in the guidance's hotel example, where a hotel with an attached restaurant and conference centre has the hotel operator, as the party controlling the premises for its principal use, as the overall responsible person (para 6.4). See who the responsible person is for the general control test behind all of this.
Where the principal-use test does, and doesn't, bring a building into scope
It applies where a Schedule 1 use is genuinely the dominant one: a building that's mostly a restaurant with a small flat above it, or a leisure centre occupying most of a council building. It doesn't automatically apply where a Schedule 1 use is a minor, incidental part of a much larger building with a different principal purpose, an office block with a small public café tucked into the ground floor is a common example, where the office use, not the café, is what's actually principal. Whether the café itself separately meets the numbers and access tests on its own footprint is worth checking too, using the part-of-building rule above, rather than assuming the office block's overall use settles the question either way.
What the standard tier actually requires
Once you've identified the right premises and its principal use, the duties themselves are the same as anywhere else: a one-time notification to the regulator, and public protection procedures covering evacuation, invacuation, lockdown and communication, in place so far as reasonably practicable. See the standard tier explained for the full detail, and who Martyn's Law applies to for the underlying four-condition test this page builds on.
What it costs, and how the service helps
Working out where the boundaries actually sit is the hard part for mixed- use and nested premises; the duties themselves cost nothing to meet at the standard tier. Our service starts with a short questionnaire about how your building is actually used and controlled, and builds the right premises boundary into your plan before working out procedures, rather than assuming a single simple answer.
Not sure which part of your building is in scope? Start with the free tier checker, no email required.
Common questions
I run a shop unit in a shopping centre. Is it me or the centre that's responsible?
Generally both, for different things. The centre operator is the responsible person for the centre as a whole, and the centre's own total is what all the individually let units sum into. Your unit is separately assessed too, though, and as the occupier in control of it, you're the responsible person for your own unit's duties. Your unit's total doesn't get inherited from or added to the centre's, and the centre's total doesn't get inherited by you.
Does a church hall attached to a church count as one premises or two?
It depends on how they're actually run. If the hall is a genuinely separate, independently controlled space, a different building or a self-contained part with its own booking system and its own operator, it may be assessed as its own premises. If it's functionally part of the same building under the same control, part of a building can qualify alongside the rest, so treat it as one premises with one responsible person rather than assuming a split by default.
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.