Once your premises is in scope of Martyn’s Law (the Terrorism (Protection of Premises) Act 2025), the next decision is which tier applies. Standard Tier and Enhanced Tier carry different duties, and the difference shapes the whole approach to readiness.

This page explains how the two tiers work, what each one requires, and the single specific exception that applies to places of worship regardless of attendance.

The Act uses expected attendance (not building capacity) as the cut-off between tiers.

The 800-individual cut-off applies to the same “reasonable to expect from time to time” test as the 200-individual scope threshold, and “individuals” counts staff, volunteers, and visitors combined.

Standard Tier is where the majority of in-scope premises sit. The duties focus on response readiness, and break into four public protection procedures:

• Evacuation. Getting people out by the nearest safe exit, away from the threat.
• Invacuation. Getting people inside and securing the premises when the threat is outside.
• Lockdown. Stopping movement, barricading, and preventing access to specific rooms.
• Communications. A system that reaches everyone on the premises, in every building, quickly.

Each procedure must be purpose-built to your premises, trained out to staff, exercised, and evidenced.

Enhanced Tier premises carry all the Standard Tier duties and add:

• Public protection measures. Physical and operational steps that reduce vulnerability: deter, detect, delay, defend. Measures are not a prescribed kit list; they’re chosen based on a risk assessment of your specific premises.
• A nominated Responsible Person. A named individual accountable for Martyn’s Law duties at the premises.
• A documented rationale. Evidence of how measures were chosen and > why those measures (and not others) are reasonably practicable.

The Enhanced Tier duties are deliberately more demanding because they apply to premises with the highest expected attendance, where the impact of an incident would be greatest.

One specific exception sits in the Act. Places of worship that would otherwise fall into Enhanced Tier (those with 800+ individuals reasonably expected from time to time) remain in Standard Tier.

In practice, this means a cathedral, large mosque, synagogue, temple, or gurdwara expecting more than 800 individuals is subject to the four public protection procedures but not the measures, Responsible Person, or documented rationale duties. The reasoning reflects the unique nature of faith premises: volunteer governance, open-door policies, and community use patterns that sit outside the Enhanced Tier model.

Getting the tier right at the start saves significant rework later. Preparing Enhanced Tier documentation for a premises that only needs Standard Tier duties is wasted effort. Preparing Standard Tier documentation for an Enhanced Tier premises leaves meaningful gaps that a regulator would spot on inspection.

If your expected attendance sits close to 800, the safer position is usually to prepare to Enhanced Tier standard. The upfront cost is higher, but it removes the risk of a regulator disagreeing with your tier call.

The fastest way to know is our free Am I in Scope? tool. A handful of questions, a clear answer, no account needed.

If you already know you’re in scope, Get Started with Prova Risk to prepare your public protection procedures, train your staff, and keep the evidence you’ll need if inspected. £399 per year per site.

• The 200-Person Threshold Explained
• Procedures vs Measures Explained
• Standard Tier vs Enhanced Tier: The Full Comparison
• What Are Public Protection Procedures?
• For Places of Worship