In most cases, yes. But how that response works, how fast it arrives, and whether the police are dispatched depend on the type of system you have, who installed it, and a detail that some alarm companies don’t explain to their customers.

This guide covers everything you need to know about monitored alarms: what they are, how they work, and what to look for when choosing one.

What is a monitored alarm?

A monitored alarm is a security system connected to a professionally accredited Alarm Receiving Centre (ARC). This staffed facility watches for signals from your system around the clock, every day of the year. When something triggers your alarm, the ARC receives an alert and initiates a response on your behalf.

In contrast, an unmonitored alarm sounds a siren or alerts your app, and relies on a neighbour, a passer-by or you to act.  

 

What is an Alarm Receiving Centre (ARC)?

An Alarm Receiving Centre is a professional monitoring facility that your system communicates with. Reputable ARCs are independently accredited, typically to the British and European standard for alarm receiving centres (BS EN 50518), and staffed around the clock by trained operators. What’s more, to be accredited, they must have a backup location to use in case of a fire, power cut, or other situation that would prevent them from using their regular premises. 

If you’re choosing a monitored alarm provider, ask which ARC they use and how it is accredited. Their quality and response protocols matter as much as the equipment itself.

 

What is the difference between monitored and non-monitored alarms?

The simplest way to think about the difference between a monitored and unmonitored alarm is as follows. 

• An unmonitored alarm alerts app users and anyone close enough to hear it. 
• A monitored alarm alerts trained professionals, wherever you are and whatever you’re doing. If it’s URN-equipped (which we explain in the next section), it can also generate a police response on your behalf. 

If you’re regularly away from home or are concerned about local crime rates, your alarm type can be the difference between peace of mind and endless worry.

 

What is a URN and why does it matter so much?

A Police Unique Reference Number (URN) is a code registered with your local police force. It allows your ARC to contact your local police force directly when your alarm or personal attack button is confirmed. The URN is registered to your system and property address and is only granted when your installer is NSI- or SSAIB-accredited and the system meets the required installation standard at the time of installation. 

Your URN matters because it determines the type of police response you get:

• Type A response (with a URN). Your ARC has a direct, priority link to your local Police Force’s Control Room. Your property details are already on file, and they’ll treat the activation as a verified, priority incident.
• Type B response (without a URN). Your ARC has no direct line to police. If it believes a break-in is happening, all it can do is call 999, like a regular member of the public. Under National Police Chief Council policy, this carries no guaranteed response time, and, worryingly, officers may not be dispatched at all.

When you’re choosing a monitored alarm system, be sure to remember this – if your installer or ARC is not accredited, your system cannot have a URN. This means it can only ever produce a Type B response, something you can’t change unless you install a new system. 

 

How do monitored alarms connect to a central alarm receiving centre (ARC)?

While not all monitored alarms are created equal, they all follow the same basic process:

1. Trigger. A sensor detects movement. This could be a door or window opening or another event. Your alarm panel will register the activation.
2. Signal sent to the ARC. Your system communicates the alert to the Alarm Receiving Centre.
3. Confirmation: A professional operator at the ARC receives the signal and then if they have confirmation, they generate a police response.

Most systems use confirmed alarm signalling to filter out false alarms. This means waiting for a second sensor to trigger before requesting a police response. For example, a door contact (indicating forced entry) and a motion sensor within the protected premises would count as two separate detection devices.  

Alternatively, a deliberately activated personal attack button will prompt a police response after ARC staff assess the situation. 

4. Response initiated. Once confirmed, the ARC contacts you and/or your nominated keyholders. They may also contact the police. If your system has a Police Unique Reference Number (URN), it alerts your local police force directly. If it doesn’t have a URN, they take a different route, which we cover in more detail shortly.
5. You stay updated. You receive a call or app notification letting you know what has happened and what response is underway.

 

What types of systems can be monitored?

Professional monitoring isn’t limited to intruder alarms. At Absolute Fire & Security, we install and monitor:

Intruder alarms. The most common type of alarm for residential and commercial properties. They are triggered by motion sensors, door and window contacts, and other detectors.

Panic and hold-up alarms. Also known as personal attack alarms, these discreet devices allow a homeowner or staff member to trigger a silent alert to the ARC and, where a URN is held, directly to police. They’re particularly important for high-value homes, lone workers and retail environments. 

Fire alarms. Monitored fire systems connect to the ARC in the same way as intruder alarms, alerting the monitoring centre to smoke or heat detection. This way the fire service can be contacted, even if no one is present at the property.

CCTV systems.  These provide visual confirmation that ARC staff can use to decide the necessary response.

Combined systems. A well-designed installation can combine all systems, integrating intruder detection, panic response, fire monitoring, CCTV, and access control into a single monitored platform, with a separate response path for each where required.

 

What is the typical police response time to a monitored alarm?

The typical police response time to a monitored alarm depends on whether your system has a URN.

With a URN (Type A). Your ARC contacts your local Force Control Room directly. Your property details are already on the system. The call is treated as a verified, priority activation – responded to within an average of 8 minutes, with all Level 1 alarms attended.

Without a URN (Type B). Your ARC calls 999. The call enters a national system, is handled wherever it lands, and is then transferred to your local force. They don’t automatically grade a non-URN alarm as an emergency, meaning some forces have a target response time of up to 60 minutes, while under NPCC national policy, they may not automatically dispatch officers at all.

 

What are the advantages of professionally monitored home security systems from an NSI Gold installer?

As well as the reassurance of a trusted response when you can’t respond yourself, monitored alarms from NSI Gold installers have three key advantages:

Recognised by insurers. Many home insurance policies require a professionally monitored, independently certificated alarm system for high-value properties or contents. Insurers want to see systems installed by an NSI Gold-approved company, with a formal Certificate of Compliance.

False alarm filtering. Professional installations using confirmed alarm signalling significantly reduce false alarms. This goes beyond immediate peace of mind because excessive false alarms can lead to police withdrawing response from a property entirely.

Verified, audited installation. An NSI Gold-approved installer, such as Absolute Fire & Security, is independently audited against BS EN 50131 — the British and European standard for intruder alarm systems. Every installation we complete is graded to that standard and backed by a formal NSI Certificate of Compliance. 

 

How much does a monitored alarm system cost in the UK?

Costs vary depending on the size of the property, the type of system, and the level of monitoring required. As a general guide:

• Installation. A professionally installed, NSI-compliant intruder alarm for a residential property typically starts at £800–£1,500, depending on the number of sensors and the required specification.
• Annual monitoring. Professional ARC monitoring typically costs around £199–£499 per year, often including planned maintenance visits. 

Some subscription-style alarm providers advertise low monthly costs but include the equipment on loan. This means you don’t own the equipment, and your total cost over a typical five-year contract can significantly exceed the outright purchase price. 

 

How do I know if my current alarm is properly monitored?

If you are unsure about the effectiveness of an existing system or a potential new monitored alarm system, ask your provider:

• Is my system monitored by an accredited ARC (Alarm Receiving Centre)?
• Do I have a valid Police URN registered to this property?
• Is my installation certified to BS EN 50131?
• Is my installer NSI- or SSAIB-accredited?
• Will I / do I own the equipment, or is it on loan?

If your provider cannot answer these questions clearly, contact Absolute Fire & Security for an honest, no-obligation assessment.

 

Am I tied to my equipment? What happens if I want to switch providers?

Before signing any alarm contract, we’d recommend you get the following confirmation in writing: 

• Who owns the equipment?
• How do you cancel, and what does this involve?
• Can another provider maintain or monitor your system in the future? 
• What are the likely lifetime costs associated with your equipment? Will costs increase after your first year’s contract expires?

The answers will tell you a great deal about how the company views its relationship with you as a customer.

 

Thinking about upgrading or reviewing your alarm?

At Absolute Fire & Security, we offer a no-obligation security assessment for homeowners and businesses across London and the South East. We’ll tell you what your current system does and doesn’t do — whoever installed it.

Get in touch to arrange your free security review →