What should happen when your alarm goes off in the middle of the night?
What should you do first if your alarm sounds overnight?
Verify the activation before anyone attends. Check the alert source, alarm zone, CCTV or app feed, and any message from the monitoring centre, then decide whether trained attendance or emergency escalation is needed. A night-time alarm needs a clear response chain, because guesses put people and premises at risk.
For commercial buildings, retail premises, managed residential blocks and high-value homes, the weak point is rarely the alarm sound itself. The weak point is the gap between the alarm going off and someone making a safe, informed decision.
We see the same risk in many informal plans. A manager receives an app alert, a resident hears the siren, or an owner gets an out-of-hours call, and the plan quietly becomes a personal trip to site. That leaves too much resting on one tired person with limited information.
A better plan is simple to understand before anything happens. It states who receives the alert, what they check first, who has authority to attend, when emergency services become relevant, and how the site is handed back after the alarm has been reset.
The first response is verification
A phone alert at night gives you a signal. It does not give you the full picture. The first job is to establish what kind of activation you are dealing with and whether any sign of immediate danger exists.
If a burglar alarm goes off at night, the first person notified should check the alarm zone, any CCTV, the app history and the Alarm Receiving Centre message where the system is monitored. Forced entry, violence, fire or an immediate threat changes the response. A routine alarm signal with no supporting evidence still needs action, but it needs controlled action.
A clear alarm activation response follows a set order:
Notification. The alert reaches the nominated keyholder, monitoring centre or response provider named in the plan.
Verification. Available information is checked before anyone goes to the premises, including zone data, CCTV and any call from site.
Attendance decision. A trained keyholder or security officer is sent when attendance is needed and safe to arrange.
Escalation. Police, fire services or another emergency route becomes relevant when the information shows crime, fire, violence or immediate danger.
Securing and reset. The responder follows the site instructions for access, alarm reset, locking up and any temporary securing.
Report. The incident log records what happened, who attended and what follow-up is required.
That order matters because each step gives the next person better information. If you are working out what to do when an alarm goes off while the phone is already ringing, the plan has failed at the point where you need it most.
Why alarm type changes the route
Alarm type controls who receives the signal, who can act on it and what evidence is needed before escalation. We want you to know the route your system actually creates, because a siren, an app alert and a police-response alarm are different arrangements.
The table below compares common alarm types with the response route each one creates.
Alarm type | Response route |
|---|---|
Audible-only intruder alarm | The siren alerts people nearby. Police attendance for most audible-only domestic alarms depends on evidence of crime or suspicious activity. |
Monitored intruder alarm | An Alarm Receiving Centre receives signals and follows the agreed notification route for keyholders or escalation. |
Police-response intruder alarm | A compliant system needs a current URN (Unique Reference Number). National Police Chiefs’ Council policy treats an activation without a current police URN as a Type B system. |
Possible fire alarm activation | Treat possible fire or smoke as life safety first. London Fire Brigade’s commercial non-attendance policy applies between 7am and 8.30pm only, and it attends all automatic fire alarms outside those hours. |
A monitored intruder alarm and a police-response intruder alarm are often confused, but they are not the same arrangement. Technical standards such as BS 8243, PD 6662 and BS EN 50518 sit behind some monitored and police-response systems, and the practical point is simpler. Your plan must match the system you actually have.
Fire alarms deserve separate judgement. London Fire Brigade says automatic fire alarms made up 34% of all incidents it attended in 2025, equal to 47,500 calls, which is why commercial premises need a proper filtering and investigation process during the day. The timing matters here. That non-attendance policy covers 7am to 8.30pm, so a night-time fire activation should be treated as life safety and escalated without delay.
Safe attendance is a controlled security task
Attendance is where poor alarm plans become risky. A proper alarm response keeps the person attending in control, not exposed at the door. For retail premises, offices, commercial sites and high-value homes, we look for a response method that keeps the responder outside the risk until the situation is clearer.
At Fahrenheit Security, we approach alarm response in Central London and Greater London as a controlled security task. The point is controlled judgement: where the responder waits, how they assess the site, who they call if something is wrong and how they record the decision.
The perimeter check comes first
Arrival should start from a safe position outside the premises. The responder checks the perimeter, looks for obvious forced entry, checks vulnerable access points and uses the available site instructions before any access decision is made.
If there are signs of a break-in, the responder should escalate before entry. A lone person entering a possibly compromised building creates avoidable risk and can disturb the situation that emergency services may need to assess.
Access needs authority
Keys, alarm codes and reset decisions should follow the client’s agreed instructions. Professional keyholding is about controlled access, clear authority and proper handover after the event. It is not simply holding a set of keys.
For Type A police-response systems, National Police Chiefs’ Council policy requires at least two keyholders who can be contacted by telephone, access the relevant parts of the premises and attend within 20 minutes of notification. Contracted private security work involving manned guarding or key holding is licensable by the Security Industry Authority, which is why casual arrangements are a poor fit for high-value sites.
Repeat activations need a written fix
Once the siren stops, the tempting answer is to treat the event as finished. That misses the useful evidence. A false activation can point to a sensor fault, a closing mistake, a user error, a maintenance issue or a weak instruction that will repeat until someone owns the fix.
A good alarm incident report captures the details that help you stop repeat alarm activation:
Time and signal. Record when the activation came in and which zone or device triggered.
Notification route. Note who was alerted, including the Alarm Receiving Centre, nominated keyholder or response provider.
Attendance outcome. State who attended, what they found and whether the premises was secure.
Action taken. Include reset, temporary securing, emergency escalation or any access issue.
Follow-up required. Send faults, repeat triggers or unclear instructions to the alarm maintainer or property lead.
Repeated false activations can affect police response arrangements under National Police Chiefs’ Council policy, and nuisance burglar alarm noise can also become a local issue. GOV.UK guidance confirms that councils in England can act where intruder alarm noise causes a statutory nuisance.
For managed buildings, nearby occupiers and retail neighbours, repeated night alarms also create a practical problem. People start treating the signal as background noise. A written fix keeps the alarm useful.
The real test is response ownership
One night-time activation tests the system in public. The stronger test happens before that, in the way responsibility has been assigned.
The strongest alarm plan is owned and rehearsed, not left to whoever answers a phone first. In our view, response ownership means the route is known, the limits are clear and the person attending has the authority and information to act safely.
Fahrenheit Security builds that thinking into professional security response by treating the alarm as part of the wider site instruction, with verification, attendance, escalation and reporting linked together. That matters most out of hours, when the people who know the building best are often asleep, off site or unavailable.
The real question is whether your current alarm response plan still works when nobody convenient is standing nearby.
Questions clients ask us about alarm response after hours
Can a hold-up alarm be used for routine shoplifting or nuisance behaviour?
No. Hold-up alarms are for situations involving a threat to a person or fear of immediate violence or a criminal act. Routine loss prevention incidents need a separate site procedure.
What is the difference between a keyholder and an alarm maintainer?
A keyholder attends, accesses the premises under authority and helps secure or reset the site after an activation. An alarm maintainer deals with faults, servicing and technical repairs to the system.
Who should receive the incident report in a managed building?
The report should go to the person or team responsible for the site instructions, such as the property manager, facilities lead or estate manager. They need enough detail to decide whether maintenance, access changes or a resident update is needed.
Can a planned closure change the alarm response arrangement?
Yes, a closure can change who is available, which areas are accessible and what risks matter overnight. We recommend checking the response route before the closure starts, especially for retail units, offices and residential blocks with shared access.
Does a silent app alert need the same attention as a loud alarm?
Yes, because the alert still shows that the system has detected something. The response starts with verification, then moves to attendance or escalation if the available information supports it.
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