Martyn's Law standard tier or enhanced tier: what is the difference?

The standard tier covers premises where 200 to 799 people may be present at once, and it asks for a responsible person and four procedures. The enhanced tier starts at 800 people and adds public protection measures, a senior individual and a document that you send to the Security Industry Authority (SIA).

The thresholds and duties come from the SIA's guidance of 17 July 2026. The SIA expects the Act to come into force in spring 2027.

How do I know which tier I am in?

Your tier depends on how many people it is reasonable to expect on the premises at the same time. The SIA says the count includes members of staff.

• Standard tier: 200 or more people at the same time, from time to time.
• Enhanced tier: 800 or more people at the same time.
• Always standard: places of worship, schools, further education and childcare premises stay in the standard tier even at 800 or more, under Schedule 1.

Below 200, your premises are outside the tiers. Events can also be in scope: the SIA describes qualifying events as public events with entry checks where 800 or more people are expected at the same time.

What are the duties side by side?

Sources: SIA guidance (17 July 2026), Act sections 18 and 19, Home Office impact assessment (16 July 2024).

What are the four procedures?

Section 5 of the Act lists the procedures both tiers need, for use if a terrorist attack is suspected or happening:

1. Evacuating people from the premises.
2. Moving people to a safer place on the premises (invacuation).
3. Stopping people entering or leaving (lockdown).
4. Giving information to people on the premises.

The duty is to have them in place so far as is reasonably practicable. For a small venue this can be a short document that staff know and rehearse.

What are public protection measures?

Only the enhanced tier must put measures in place. The SIA lists four kinds:

• Monitoring, for example CCTV.
• Movement, meaning control of how people enter, leave and move around.
• Physical security of the building.
• Security of information, so that operational details that could help an attacker stay restricted.

The duty is to do what is reasonably practicable for your site. The Home Office impact assessment gives a sense of the range: hostile vehicle mitigation barriers at about £20,000 per premises, down to trauma first aid kits at about £60.

What goes in the enhanced tier document?

The SIA says enhanced tier premises must document their public protection procedures and measures, assess how they reduce the risk of physical harm and the vulnerability of the premises or event, and send this document to the SIA. They must also assign a senior individual, a member of staff involved in the management or control of the organisation, to be responsible for compliance.

Who needs outside help?

Standard tier premises can often use the free guidance from the SIA and ProtectUK, which says premises "do not need to spend money on consultants to be compliant". Enhanced tier sites more often buy help with the document and the measures. No adviser can certify that you comply, and neither the SIA nor the Home Office endorses any company.

Next step

Answer six questions in the tier check. You see your likely tier, the duties in this table that apply to you and the free guidance, before we ask for any details.