What actually triggers a police response?
When a burglar alarm activates, the police do not monitor it directly. That job belongs to an Alarm Receiving Centre (ARC) - a permanently staffed facility that receives signals from your system around the clock. If the ARC identifies a genuine intrusion, it uses a direct reporting link to notify the police.
But here is the critical point: the police will only respond if your system holds a Unique Reference Number (URN).
A URN is a registration code issued by your local police force that puts your premises on the list of properties eligible for police attendance when an alarm activates. Without one, the ARC has no route to a police response - no matter how good your equipment is.
The five things your system must have
For a URN to be issued, your alarm system must be:
- Designed by an NSI or SSAIB-registered company
- Installed by an NSI or SSAIB-registered company
- Maintained by an NSI or SSAIB-registered company
- Monitored by an NSI or SSAIB-registered ARC
- Registered with the local police - via an application made by the approved company on your behalf
You cannot apply for a URN yourself. Only the NSI or SSAIB-registered installer can make that application.
You will also need to nominate at least two keyholders - trusted individuals who are trained to operate the alarm, contactable by phone and able to attend your premises within 20 minutes of being notified. The NPCC Police Requirements for Security Systems 2026 sets these criteria and is clear that a keysafe is not an acceptable alternative.
Why the police insist on NSI or SSAIB approval
The scale of the false alarm problem explains everything.
Industry data consistently shows that the overwhelming majority of alarm activations are false - triggered by user error, poor maintenance, or sub-standard installation. False alarms consume police resources and delay response to genuine emergencies. The NPCC Police Requirements for Security Systems (the framework governing police alarm response across England, Wales, and Northern Ireland) exists specifically to filter out unreliable systems.
NSI (National Security Inspectorate) and SSAIB (Security Systems and Alarms Inspection Board) are both UKAS-accredited certification bodies - independently audited by the UK Government’s accreditation authority. Companies they certify undergo regular inspections to confirm they install and maintain systems to the current British Standards: PD 6662:2017 (the UK framework for intruder alarm systems) and BS 8243:2021 (the confirmed alarm standard that defines how a genuine intrusion signal is corroborated before police are called).
NSI Gold-approved and SSAIB-registered companies are the only installers the police trust for URN-eligible systems. That is not a preference - it is a policy condition.
What NOT to do
You cannot shortcut this by:
- Researching what equipment NSI Gold and SSAIB companies use
- Purchasing equivalent products online
- Fitting the system yourself
Even if you use identical hardware, a DIY or unregistered installation does not qualify for a URN. The approved company is responsible not just for the equipment - it is responsible for the design, commissioning, ongoing maintenance, and the standards compliance that the URN application is based on. No approved company, no URN.
Systems installed by handymen, general electricians, locksmiths, or non-approved security firms do not qualify, regardless of the equipment used.
Confirmed alarms: why your system needs to corroborate itself
A key requirement under BS 8243:2021 is that systems eligible for police response must generate a confirmed alarm - not just a single detector activation.
A confirmed alarm means the system has corroborated the intrusion through additional evidence before the ARC contacts police. This is typically done by:
- Sequential confirmation - two independent detectors in different zones both activate within a set time window
- Audio confirmation - ARC operators listen via microphones installed at the premises
- Visual confirmation - ARC operators view CCTV footage of the activated area
This is the technical mechanism that separates a genuine intrusion signal from a false alarm. Only confirmed signals from systems with a valid URN are eligible for immediate police attendance under the NPCC policy.
Maintenance is not a luxury
Your system must stay maintained - this is a condition of holding a URN, not an optional add-on.
Unmaintained systems drift. Sensors lose calibration, batteries fail, and software becomes outdated. The result is false alarms - and false alarms put your URN at risk.
Under the current NPCC Police Requirements for Security Systems:
- After two false alarm calls in a rolling 12-month period, you receive a written warning
- After three false alarm calls in any rolling 12-month period, police response is withdrawn (Level 3 - no attendance)
- There is no Level 2 (delayed response) in England, Wales, or Northern Ireland - it was abolished. Your system goes directly from Level 1 (active response) to Level 3 (no response)
- Reinstatement requires identifying and rectifying the fault, plus 90 consecutive days free of false alarms
Hold-up alarms (panic buttons) have even tighter thresholds: a written warning after one false call; withdrawal after two.
For Grade 3 commercial systems - the standard grade for most business premises - the minimum maintenance requirement is two engineer visits per year (or one site visit plus one remote system check), as specified under BS 9263:2016. Blake Fire & Security Systems handles scheduled maintenance as part of its rolling service agreements, with no long-term lock-in.
NSI or SSAIB monitoring - and what the ARC actually does
Your ARC must also hold NSI or SSAIB approval. The ARC receives the confirmed alarm signal, verifies it against your system’s registration, and uses an electronic reporting route to notify the police.
Since April 2021, many forces have adopted ECHO - an electronic call handling system that transmits alarm data directly from the ARC to police control rooms, eliminating voice relay and saving up to four minutes in response time. Essex Police and the Metropolitan Police were among the first forces connected to ECHO in 2021.
Blake Fire & Security Systems monitors its customers’ alarms through Southern Monitoring, an NSI Gold-approved ARC. Signals are transmitted via CSL DualCom dual-path technology - two independent communication routes (IP and cellular) - so that if one path is cut or fails, the other continues to function. Insurers for most commercial premises require dual-path signalling as a condition of cover.
What happens if your current installer was not NSI or SSAIB registered?
If your alarm was installed by a non-approved company, or your previous approved installer has ceased trading or had certification withdrawn, your URN may be invalid or non-existent.
Blake Fire & Security Systems offers alarm system takeovers - taking over maintenance of an existing system, assessing it against current standards, and where the system meets PD 6662:2017 requirements, applying for or reinstating a URN. If the system is below the required standard, the team will advise on the most cost-effective upgrade path.
What it looks like in practice: a 46-year track record
Blake Fire & Security Systems has been installing NSI Gold-approved and SSAIB-registered alarm systems across Essex and London since 1979 - 46 years of family-run, accreditation-led service.
“On the 21st December of last year, I had a complete breakdown of the school’s intruder alarm… Within hours I had two engineers on site… I am extremely satisfied with all of the disciplines provided by Blakes and I am happy to continue to use Blakes for many years to come.”
Leonard Levey, Site Manager, St Anne Line Junior Catholic School
The Dedication to Accreditation principle is simple: if Blake’s is not qualified to provide a service, it will not offer it. Every system is designed, installed, and maintained by specialists - and every alarm eligible for police response is registered with a valid URN.
In the news: why alarm reliability continues to matter (2024 - 2025)
Burglary in England and Wales totalled 264,963 offences in the year ending June 2024 - a 3% decrease on the previous year, but still a significant ongoing risk to businesses and homeowners (Office for National Statistics, Crime in England and Wales: Year Ending June 2024). These figures underline why police operational policy tightly controls the response criteria for monitored alarms.
The all-IP network transition is also directly relevant. BT’s phased withdrawal of the PSTN (traditional telephone line) network means systems still using PSTN signalling to contact their ARC face disruption. NSI and SSAIB-registered companies are required to maintain current signalling technology. Blake Fire & Security uses CSL DualCom digital signalling, which is IP and cellular-based and unaffected by the PSTN closure.
Frequently asked questions
What is a URN and how do I get one for my alarm system?
A URN (Unique Reference Number) is a registration code issued by your local police force that puts your premises on the list eligible for police attendance when an alarm activates. You cannot apply for one yourself - only the NSI or SSAIB-registered company that installs and maintains your system can make the application. The system must comply with PD 6662:2017 and BS 8243:2021, and be monitored by an NSI or SSAIB-registered ARC. Blake Fire & Security Systems handles the full URN application as part of every installation.
How many false alarms before the police stop responding to my alarm?
Under the current NPCC Police Requirements for Security Systems, police response is withdrawn (Level 3) after three false alarm calls in a rolling 12-month period. There is no Level 2 (delayed response) in England, Wales, or Northern Ireland - it was abolished. Your system goes directly from Level 1 (active response) to Level 3 after three false calls. A written warning is issued after the second. Reinstatement requires fixing the fault and 90 consecutive days free of false alarms.
Can I install an NSI-grade alarm myself to get police response?
No. A DIY installation, or one by an unregistered installer, will not qualify for a URN regardless of the equipment used. The NPCC requires the system to be designed, installed, maintained, and monitored by an NSI or SSAIB-registered company. Buying equipment online and fitting it yourself will not produce a URN-eligible system.
Get your free survey from Blake Fire & Security
Whether you are installing a new monitored alarm, transferring maintenance of an existing system, or reinstating lapsed police response, Blake Fire & Security Systems offers a free, no-obligation survey for businesses and homeowners across Essex and London.
Call: 01702 447800
Email: info@blakefire-security.co.uk
NSI Gold approved · SSAIB registered · Protecting Essex since 1979
