Martyn’s Law – Home Office Guidance issued to assist duty holders

The Terrorism (Protection of Premises) Act 2025 (the “Act”), also known as Martyn’s Law, received royal assent in April 2025. The Act will require premises and events that meet certain requirements to put in place security measures to reduce the risk and impact of a terrorist attack.

The legislation is currently in an implementation period and is not expected to be enforced until April 2027 with the government cognisant that duty holders will need sufficient time to assess and implement any necessary measures to make sure they comply with the Act.  

To assist duty holders in their preparation for Martyn’s Law, the Home Office recently published statutory guidance (the “Guidance”). The Guidance is intended to provide further clarification to assist those responsible for premises and events in scope of the Act to determine (amongst other things):

• whether their premises would be considered ‘qualifying premises’ (Chapter 4);

• whether their events will be considered a ‘qualifying event’ (Chapter 5);

• who will be responsible for premises and events within scope of the Act (Chapter 6); and

• what the requirements are for those falling under the standard and enhanced tier (Chapters 7&8)

The Guidance is supported by materials produced by the National Counter Terrorism Security Office (NaCTSO) and the National Protective Security Authority (NPSA) which provide information on training resources for the more practical element of protective security.

Most helpfully, the Guidance includes illustrative examples of how the Act may apply to real world examples to aid understanding.

Guidance has also been published by the regulator with responsibility for enforcing the requirement under the Act, the Security Industry Authority (the “SIA Guidance”). The SIA Guidance is still in draft form and is undergoing consultation before being finalised and taking effect. The consultation closes at 11:59pm on 12 June 2026.

The duty in a nutshell

The Act introduces a tiered system, based on the number of attendees reasonably expected at an event or premises at any one time. The standard tier (200-799 attendees) requires duty holders to consider reactive public protection procedures in the event of terrorist attack - such as evacuation, invacuation, lockdown and communication. These public protection procedures are set out and explored within Chapter 7 of The Guidance.

The enhanced tier (800 or more attendees) imparts more robust requirements on duty holders not only to put in measures to appropriately react in the event of a terrorist attack (i.e. the same obligations to standard tier duty holders) but also to have in place appropriate preventative measures, as per Chapter 8 of the Guidance. This includes physical safety measures such as installing barriers and controlling the movement of attendees in to, out of and within the premises or event.

Duty holders under the Act are called Responsible Persons. This is the individual, organisation or company that has control of the premises for the purposes of their Schedule 1 use (see below) or qualifying event.

In this article, we will explore the key takeaways from the Guidance against the statutory responsibilities of duty holders in relation to qualifying premises and qualifying events, to help those responsible for publicly accessible premises and events assess whether they are likely to be subject to the duties under the Act.

Qualifying premises

The criteria for Qualifying Premises are set out in Section 2 of the Act and are explored further within chapter 4 of the Guidance. Qualifying Premises must meet the following requirements to fall within scope:

1. The site meets the definition of premises in the Act

The site must be a building, or a building and other land. Notably this will include part of a building, or a group of buildings that share close geographical proximity, i.e. a university campus.  4.14 of Chapter 4 of the Guidance explains that where smaller premises exist within larger premises, both may be caught by the Act if it is reasonable to expect 200 people will be present in the smaller premises at any one time. However if a smaller shop, for example, within a larger premises (i.e. shopping centre) will not reasonably expect 200 or more people present at any one time, the smaller shop will not be considered a Qualifying Premises, even if the shopping centre is.

2. The premises are wholly or mainly used for one or more of the uses specified in Schedule 1 of the Act.

Schedule 1 uses include entertainment, food and drink and visitor attractions. Chapter 4, Figure 3 of the Guidance sets out further examples of Schedule 1 uses such as village halls, community centres, hotels, hostels and holiday parks.  

Premises will often have more than one use, and therefore it will be important to establish how the premises are used for most of the time, and whether the premises have a principal use.

3. It is reasonable to expect that, from time to time, 200 or more individuals may be present at the same time.

The Guidance states in Paragraphs 4.23 and 4.24 of Chapter 4 that a reasonable method should be used to calculate the greatest expected number of individuals at the premises at the same time, considering the busiest trading time, and including staff working on the premises.

Accompanying the Guidance, the Home Office has published some non-statutory guidance to assist potential duty holders in assessing capacity (supplementary document A). Examples of methods of assessing capacity include:

• Safe occupancy for fire safety purposes

• Historic attendance data

• Fixed seating or standing positions

• Tickets and pre-registration numbers

• Restrictions

• Any other means of assessing capacity that be justified and backed up with data

  • The key takeaway is that the method of assessing capacity is not one size fits all, but must be reasonable and capable of justification. For example, at Paragraph 4.31, the Guidance gives the example of a shop having a maximum occupancy figure of 300 based on its fire risk assessment with historic attendance records showing that the shop usually has well below 200 individuals on the premises at the same time. Therefore, those responsible initially consider the shop to be out the scope of the Act. However, if the shop has peak periods during bank holiday and sales periods, it is likely to fall within scope of the Act as it is reasonable to expect over 200 people on the premises “from time to time.”

    4. The premises are not Excluded Premises

    Schedule 2 of the Act specifically excludes certain premises from falling within scope of the Act. These include:

    • Premises used for legislatures and devolved administrations.

    • Parks, gardens and recreation grounds where access is not ordinarily restricted. Paragraph 4.35 makes clear that these are excluded from the scope unless there are measures in place to check that members of the public have either paid to be there or are members of an association that allows them to be there.

    • Transport premises that are already subject to enhanced security requirements.

    Premises subject to different thresholds

    A key proviso of the Act, explored further at Paragraph 4.36 of the Guidance, states that certain premises will receive special treatment under the Act which means they will remain in the standard tier even if the expected number of individuals in attendance is 800 or more. This includes places of worship and primary and secondary education facilities, but not higher education facilities. The effect of this is that even if it is expected that over 800 people will be present, the premises will only be caught by the standard tier requirements, and not the enhanced tier requirements.

Qualifying events

An event will be considered a “Qualifying Event” if there are expected to be 800 or more people in attendance but it is not being hosted at a premises that is already considered as a “Qualifying Premises” within the enhanced tier.

There are six criteria to determine whether an event is a Qualifying Event for the purpose of the Act, explored within Chapter 5 of the Guidance:

1. The event takes place at premises as defined in s (3)(1) of the Act

This is a wider definition than the definition for Qualifying Premises, as it also includes land without buildings. It will therefore cover, for example, music festivals that take place in a field (Paragraph 5.8).

2. The event takes place at premises not already covered by the Act as enhanced tier premises

This simply means that if an event is already taking place at a Qualifying Premises where it is reasonably expected there will be 800 or more people in attendance at any one time, it will not be caught twice by the Act (i.e. under both Qualifying Premises and a Qualifying Event). The duties for a Qualifying Premises within the enhanced tier will apply.

3. The event is accessible to the public

This criterion will be satisfied if the public can, in principle, attend the event, even if there are some restrictions, or tickets ultimately sell out for the event. Some examples of events that are not open to the public include wedding receptions or private awards dinners, as set out in Paragraph 5.13.

4. It is reasonable to expect that, at some point during the event, 800 or more individuals may be present

Similar methods of calculation can be used as when working out the capacity for Qualifying Premises. In practice, it may be slightly simpler to calculate expected attendance for a Qualifying Event, as there will more than likely be a condition of entry, such as a ticket purchase required. Organisers can therefore judge expected attendance based on the number of sign-ups, or tickets sold.

5. The event has measures in place to check that attendees satisfy an entry condition

Examples of entry conditions that will satisfy this criterion include ticketed events or a requirement for the attendee to be a member or guest of a club or association however conditions such as imposing a specific dress code or suggested voluntary donations will not suffice. Further examples of conditions of entry are given at Paragraphs 5.22-5.26 of the Guidance.

6. The event is not taking place at excluded premises

Where a potentially Qualifying Event is held in premises that have special consideration for enhanced tier purposes (i.e. places of worship, schools etc) or at excluded premises (i.e. houses of parliament etc) it will not be considered a Qualifying Event.