What is the difference between Protect Duty and Martyn's Law?

There is no difference in substance: Protect Duty and Martyn's Law are the same policy at different stages. Protect Duty was the working name the Home Office used for the 2021 consultation and the early drafts; Martyn's Law is the campaign name, after Martyn Hett, one of the 22 people killed in the Manchester Arena attack in May 2017; and the law itself is the Terrorism (Protection of Premises) Act 2025, which received Royal Assent on 3 April 2025 and is expected to commence in spring 2027.

From the floor. Search GOV.UK for Protect Duty and you land on 2021 consultation papers and the 2023 draft Bill, whose thresholds did not survive into the Act. The 100-capacity standard tier is the one that catches people out: it became 200 in the final Act. If a supplier's compliance material still talks about 100-capacity premises, it is working from the draft. (Toni Moss, Managing Director and Owner)

Three names, one law

Capacity is counted as everyone reasonably expected to be on the premises at the same time, including staff, diners and event attendees, not bedrooms or seats.

What the final Act requires

Standard tier (200 to 799 people):

• Notify the Security Industry Authority (SIA) within three months of commencement; there is no fee.
• Name a responsible person for the premises.
• Put public protection procedures in place, so far as reasonably practicable, for evacuation, invacuation, lockdown and communication.
• Make sure staff know how to carry those procedures out.

Enhanced tier (800 or more people, and qualifying events of 800 or more with entry checks):

• Everything in the standard tier.
• Public protection measures across four categories: monitoring, movement, physical safety and security, and security of information.
• A documented compliance statement describing the procedures and measures, provided to the SIA.
• A designated senior individual where the responsible person is an organisation, with personal liability for consent, connivance or neglect.

The Act does not prescribe any technology or product; the duty is to procedures and, at the enhanced tier, measures, and the AV and communication systems that support them are chosen by the responsible person. Scope, tiers and the full dated timeline are set out in the Martyn's Law guide, and the Martyn's Law compliance service maps the four procedures onto existing voice alarm, signage and notification infrastructure.

Quick reference: same law, three names: Protect Duty (2021 consultation working title), Martyn's Law (campaign name), Terrorism (Protection of Premises) Act 2025 (the statute; Royal Assent 3 April 2025, commencement expected spring 2027); standard tier 200-799, enhanced tier 800+ and qualifying events 800+.