When your burglar alarm triggers at 2am, what actually happens? If you have professional alarm monitoring in the UK, the answer involves a highly trained operator sitting in an Alarm Receiving Centre (ARC) who receives your alarm signal within seconds, assesses the threat, and decides whether to call your keyholders, dispatch a guard, or request a police response. If you don’t have monitoring, nothing happens except your siren waking the neighbours. Understanding how alarm monitoring companies work — and which one is right for your home — is one of the most useful things you can do when investing in a security system.
This article contains affiliate links. If you buy through them, we may earn a small commission at no extra cost to you. This doesn’t affect our editorial independence — we only recommend products we’d genuinely suggest to a friend.
An Alarm Receiving Centre is a dedicated, staffed facility that receives electronic signals from alarm systems and takes action on them. In the UK, reputable ARCs are certified to BS EN 50518, the European standard for monitoring centres, which requires physical security at the monitoring facility itself, redundant power supplies, and trained operators following defined response protocols. The National Security Inspectorate (NSI) and SSAIB (Security Systems and Alarms Inspection Board) both audit ARCs against this standard.
When your alarm activates, the signal travels from your alarm panel — typically over a dual-path connection using both broadband and a 4G SIM as a backup — to the ARC. The dual path matters: if a burglar cuts your phone line or broadband, the 4G backup still delivers the signal. Single-path monitoring (broadband only) is cheaper but significantly less reliable in a real attack scenario.
The response sequence after an alarm activation typically follows this order:
UK police forces will not respond to an alarm signal unless the alarm system has a registered Unique Reference Number (URN). To obtain and maintain a URN, your system must meet specific requirements — the key ones being:
It’s worth noting that even with a URN, police response is not guaranteed — forces are under significant resource pressure, and response times vary widely. The URN simply means police may respond; a guard response contract gives you a guaranteed attendance time. You can read more about how monitoring connects to alarm certification in our guide to burglar alarm monitoring in the UK.
The UK monitoring market has a handful of dominant providers alongside specialist regional players. Here’s an overview of the major names:
ADT is the UK’s largest alarm monitoring company by installed base, with their own NSI Gold-certified ARC. They offer monitored alarm installations under their own brand as well as monitoring-only contracts for existing systems. ADT’s residential monitoring contracts start at around £20–£25/month and include keyholder response and police URN support. Their monitoring centre is ISCEC (Industry Standard Contract for Electronic Communications) compliant.
Verisure is a European market leader that has grown rapidly in the UK. Their proposition is a proprietary all-in-one alarm with built-in camera verification and a private guard response network. When your Verisure alarm activates, an operator sees a video clip from the alarm’s internal camera before deciding to dispatch. They operate their own ARC (NSI Gold certified) and their own response teams in major cities. Pricing starts around £35–£40/month on a 36-month contract, making them among the more expensive options — but the guard response and video verification are genuinely differentiated.
Custodian Monitoring is one of the UK’s largest independent wholesale ARCs, meaning they provide monitoring services to alarm installation companies rather than direct to homeowners. If your local NSI or SSAIB alarm company says your system will be “monitored by Custodian,” this is a credible, professional ARC with NSI Gold ARC certification. Many high-quality independent alarm installers route their monitoring through Custodian or similar wholesale ARCs.
Calder Security is a Yorkshire-based alarm company with its own in-house ARC, NSI Gold certified. They operate nationally and offer monitoring from around £15–£20/month. A solid mid-market choice with strong customer service reputation and no lock-in contracts beyond the initial installation.
Pyronix (owned by Hikvision) produces one of the most widely installed professional alarm panels in the UK — the Enforcer range. Their cloud platform allows alarm installers to offer app-based remote access and monitoring. Monitoring through Pyronix-connected ARCs varies by installer; the panel itself is NSI/SSAIB certifiable. If your installer uses Pyronix Enforcer, ask who their ARC partner is and confirm it is NSI Gold certified.
Prices shown are approximate monthly monitoring fees for a typical residential property. Installation costs are separate and vary significantly. Always get at least three quotes.
| Provider | Monthly cost | Response type | NSI/SSAIB ARC | Police URN | Contract |
|---|---|---|---|---|---|
| ADT | £20–£25 | Keyholder + police URN | NSI Gold | Yes | 12–24 months |
| Verisure | £35–£45 | Guard response + video verification | NSI Gold | Yes | 36 months |
| Calder Security | £15–£20 | Keyholder + police URN | NSI Gold | Yes | 12 months |
| Custodian (via installer) | £12–£18 | Keyholder + police URN | NSI Gold | Yes | 12 months |
| Ring Protect Pro (self-monitored) | £10/month | 24/7 professional monitoring via Noonlight (US-based) | No NSI/SSAIB | No | Monthly |
| Yale Smart Alarm (app only) | £0 (self-monitoring) | App notification only | No | No | N/A |
Understanding what your monitoring contract actually delivers is critical. There are three main response types:
The ARC calls a list of people you’ve nominated — typically two or three contacts — to attend your property. This is included in virtually all monitoring contracts. The limitation is obvious: if your keyholders are unavailable, asleep, or too far away, no one attends. For most homes in populated areas, keyholder response is sufficient because the siren and deterrence value of a monitored alarm mean most burglars leave before a keyholder arrives anyway.
If your system has a URN, the ARC can contact police. As noted above, a confirmed/verified alarm protocol is required. The National Police Chiefs’ Council guidance requires that only signals from URN-registered, properly maintained systems receive police response. Police response time varies enormously — in rural areas it may be 30–60 minutes; in cities, often faster. Do not rely on police response alone for high-value properties.
A uniformed, licensed Security Industry Authority (SIA) guard attends your property within a contracted response time, typically 20–45 minutes. Guard response is available as an add-on through companies like Verisure (built in), ADT (available as an upgrade), and most regional alarm companies via guard response partnerships. Expect to pay an additional £10–£20/month for this service. It is most valuable for high-value homes, remote properties, or homeowners who travel frequently and have no reliable local keyholders.
Professional alarm monitoring in the UK typically costs £10–£30 per month for a residential property, plus any line rental or SIM costs for the signalling path. The total annual cost therefore ranges from around £120 to £360. The variation depends on:
If you are getting quotes from installers, always ask them to specify which ARC they use and confirm it holds NSI Gold or SSAIB certification. For more detail on what NSI certification means for your alarm, see our guide to NSI-approved alarms in the UK.
Products like Ring Alarm, Yale Smart Alarm, and Honeywell Home offer app-based self-monitoring for free or a modest monthly fee. For many homes, this level of monitoring is entirely adequate — you receive an instant notification on your phone the moment the alarm triggers, and you can view live camera footage and decide whether to call police yourself. The shortfall is the absence of a certified ARC and the inability to obtain a police URN.
The practical difference matters most at night, when you are away for extended periods, or when your mobile signal is unavailable. A certified ARC is always staffed, acts on your behalf without you needing to be alert, and can request police response through official channels. If you travel regularly or own a second property, professional ARC monitoring is worth the additional cost.
For a full breakdown of how monitoring connects to insurance eligibility, see our guide to insurance-approved alarm systems in the UK.
When evaluating alarm monitoring companies, ask these five questions:
Professional alarm monitoring is one of the most effective upgrades you can make to a home alarm system. The £15–£25/month investment in an NSI-certified ARC contract buys you 24/7 coverage, police URN eligibility, and the confidence that someone is always watching — even when you’re asleep, travelling, or simply unable to answer your phone. Compare quotes from at least three NSI or SSAIB-approved companies and ask them each to specify their ARC partner before committing.
Finding a genuinely certified alarm installer in the UK takes more than a Google search. Here's how to verify NSI…
Buying a smart alarm is easy — but many homeowners discover it doesn't qualify for an insurance discount. Here's what…
There are three main types of burglar alarm available to UK homeowners, and they are not interchangeable. Here is what…