Monitoring is the first protective measure the guidance names. Here is what it actually means.
Enhanced tier venues must document protective measures across four categories. Monitoring leads the list, and it is the one your existing cameras can already carry, if they are watched.
In one line
Under Martyn's Law, monitoring means an enhanced tier venue can spot a developing threat in time to respond, and can document how. Guidance gives CCTV as the example. The measure is judged on whether it works, which for most venues turns on one question: is anything actually watching the cameras?
01 · Where monitoring sits
Where does monitoring sit in the Act?
The Terrorism (Protection of Premises) Act 2025 requires enhanced tier venues, premises and events where 800 or more people can reasonably be expected, to put proportionate protective measures in place and document them for the Security Industry Authority. Guidance organises those measures into four categories: monitoring, movement of people, physical security and security of information.
Monitoring covers the venue's ability to identify threats in and around the premises: hostile reconnaissance before an attack, a person somewhere they should not be, a situation building at an entrance or exit. CCTV is the example the guidance gives, which makes it the natural backbone of the category for any venue that already owns cameras.
The word the Act leans on is proportionate. A 900 capacity venue is not expected to build a control room with a dozen operators. It is expected to show that its monitoring genuinely works for its site and its risks.
02 · The test
What separates monitoring from recording?
Response time. A recorded camera contributes after the fact. A monitored camera contributes while there is still a decision to make: hold the doors, send a steward, start the lockdown procedure, call it in. Martyn's Law exists because minutes matter, and its four required procedures, evacuation, invacuation, lockdown and communication, all start faster when someone sees the trigger early.
The hard part is scale. Nobody can watch forty feeds, and hiring eyes for every screen is not proportionate for most operators. This is where detection software earns its keep: every camera watched at once, and only the moments that need judgement brought to a person.
03 · In practice
How does Archangel handle the monitoring category?
- Connects to your existing IP cameras through RTSP or ONVIF, live in under 48 hours
- Watches every feed through 15+ behaviour detection layers: restricted zones, crowd build-up, loitering, person down, queue pressure at ingress and egress
- Alerts your team in seconds with the camera, the location and a clip
- Logs every detection and response, so the documentation the SIA asks for is generated by operating, not written from memory
- No facial recognition, no biometric data stored, UK built and UK hosted
Monitoring is one category of four, and software is one part of it. Your procedures, your people and your documented risk assessment carry the rest. Anyone who tells you otherwise is selling you a shortcut the Act does not recognise.
04 · Questions
Monitoring questions, answered straight
What does monitoring mean under Martyn's Law?
For enhanced tier venues, official guidance names monitoring as one of four categories of protective measures, alongside movement of people, physical security and security of information. Monitoring means the venue can identify a developing threat in and around the premises in time to respond, and CCTV is the example the guidance itself gives. The Act does not prescribe how you monitor. It asks that the measure reduces vulnerability and that you can document how.
Is monitoring required for standard tier venues?
No. Standard tier venues (200 to 799 people) are required to have response procedures: evacuation, invacuation, lockdown and communication. Monitoring is not a legal requirement at this tier, though cameras that are actually watched make every one of those procedures faster and better informed.
Does someone have to watch the cameras all the time?
The Act does not set staffing rules, and for most venues a person watching every feed all night is not realistic. That is the practical case for detection software: it watches every connected camera simultaneously and brings the moment that needs human judgement to a human, rather than asking a human to find it among forty screens.
What evidence of monitoring will the SIA expect?
Enhanced tier venues must document their protective measures, explain how they reduce vulnerability and harm, and submit that documentation to the SIA. For monitoring, the strong version of that evidence is operational: what the system watches, what it flags, who responds and how fast, with logs to show it happening. A camera map alone says you own cameras. A detection and response log says you monitor.
Can hostile reconnaissance really be spotted on CCTV?
Counter-terrorism guidance from ProtectUK treats identifying hostile reconnaissance as a core aim of protective security: people testing security responses, loitering with sightlines to queues and entrances, or paying unusual attention to exits. Behaviour detection can flag the observable patterns, such as prolonged loitering or repeated presence in sensitive areas, so staff can make the judgement call. No system reads intent, and any vendor claiming to detect terrorists is selling fiction.