Standard or enhanced tier: what each one actually requires
Premises expecting 200 to 799 people are standard tier. 800 or more is enhanced tier. Standard tier means notifying the SIA and having public protection procedures. Enhanced tier adds registration, documented public protection measures, and a security document that must be re-provided within 30 days of every revision.
What decides the tier
One number: how many individuals may reasonably be expected to be present at the same time. 200 to 799 is standard tier. 800 or more is enhanced tier.
That figure includes staff. It is not your fire capacity, your licensed capacity, or your ticket allocation, though any of those may be evidence for it.
What standard tier requires
Notify the SIA that you are responsible for the premises, and have public protection procedures: evacuation, invacuation, lockdown and communication.
That is the whole of it. There is no requirement to buy equipment, install physical measures, or submit your procedures to anyone.
What enhanced tier adds
Register with the SIA, put public protection measures in place and keep them under review, and maintain a security document describing them.
The document must be provided to the SIA, and re-provided within 30 days of every revision. That clock restarts each time you change the document, which is the part most easily missed.
Enhanced tier premises must also have a designated senior individual responsible for compliance.
The exception that catches people out
Some premises are held at standard tier no matter how many people they hold. Places of worship, childcare, and primary, secondary and further education never move up to enhanced tier on capacity alone.
Higher education is not in that group. A university lecture theatre or students' union at 800 or more is enhanced tier.
Enter your premises and expected occupancy. You get the tier for each site and the reasoning behind it. Free, no account.