Martyn's Law guidance: which official document to read

There are two sets of official guidance on Martyn's Law. The Home Office guidance explains what the duties are. The Security Industry Authority (SIA) guidance explains how the regulator will work. Neither is the law, but the Act gives the Home Office guidance a particular legal weight.

Which guidance should you read first?

It depends on your question.

What are the two documents?

Both are published on GOV.UK and linked in the sources below. Start with the Home Office guidance for scope and duties. Read the SIA guidance for what happens when the duties begin.

Why does section 27 matter?

Section 27 of the Act requires the Secretary of State to publish guidance about the requirements in Part 1, to keep it under review, and to lay it before Parliament. It also sets an evidential rule.

If it is alleged in proceedings that a person has contravened a requirement, proof that they acted in accordance with applicable section 27 guidance may be relied on as tending to establish that there was no contravention.

That has two consequences.

• Following the guidance is evidence, not immunity. The wording is "may be relied on as tending to establish". It supports a defence. It does not guarantee one.
• Departing from the guidance is allowed, but needs a reason. The guidance is not binding. If you take a different approach, you lose the benefit of the rule, so you need a recorded reason that stands on its own.

In both cases, the record of what was decided, on what basis and against which guidance is what carries weight.

What does the SIA guidance add?

The SIA's guidance rests on section 12 of the Act. That section requires the SIA to prepare guidance on how it proposes to use its functions, and to give advice on the requirements. Those parts of section 12 came into force on 15 June 2026 under SI 2026/622.

The SIA guidance describes how the regulator will check compliance, through desk-based assessment and on-site inspection. It describes how notification will work. It also says the SIA expects the Act to come into force in spring 2027, and that people will be invited to test the notification portal from early 2027.

Those are statements of expectation, not a commencement date. Only the Secretary of State can set that, by regulations. The commencement note shows what is in force and what is not.

How do you use the guidance?

1. Start with scope. Whether your premises or event qualify, and at which tier, decides which duties apply. The scope checker applies the Act's tests. The Act guide states them with section references.
2. Read the duties for your tier. Standard and enhanced duty premises have different requirements, and the guidance is organised by tier.
3. Check what you must notify, and when. Notification has its own deadlines and content, set by regulations. The notification note summarises both.
4. Record your reasoning. Because section 27 turns on acting in accordance with guidance, keep a dated record of which guidance you applied to which premises and what you decided.

The procedure gap checker shows which evacuation, invacuation, lockdown and communication arrangements you already have. The plan builder turns them into a one-page plan for standard-tier premises. The staff briefing pack records that your team has been briefed. All three are free and store nothing.

What does the guidance not do?

It does not decide scope for a particular building. The guidance explains the tests. Applying them to a specific site, such as a mixed-use building or an event with a variable capacity, is a decision for the Responsible Person.

Responsibility for compliance under the Act cannot be passed to an adviser.