An intruder alarm system is a commonly used security measure that prevents or mitigates a variety of crimes (burglary, robbery, malicious damage and arson) at home and business premises and is widely recognised by insurers – subject to the alarm system meeting some basic criteria.

If you are planning to have an alarm system installed it is worth being aware of what your insurer may typically be looking for if they are to recognise the alarm system as meeting your security needs or, perhaps, as being worthy of a premium discount.

The guidance notes that follow are therefore intended to provide you with an overview of the key choices underpinning the process of buying a new alarm system and provide an insight into some typical related insurer expectations. The guidance is necessarily general, so before proceeding with any purchase it is advisable to check with your insurance provider.


The installation of an alarm system is a significant investment in the security of your premises, so it makes sense to ‘get it right first time’. If you succumb to the temptation to simply select the cheapest alarm quotation, you may end up with a system that fails to fulfil your, or your insurer’s, expectations, and you may also have bought a system that cannot later be easily altered.

It is therefore very important to seek insurer advice/approval before purchase.

Before reading the guidance notes that follow, it is helpful to understand the two fundamental types of alarm system that are available, i.e. ‘unmonitored’ or ‘monitored’, and consider which type may best suit your, or your insurer’s, purposes.

Unmonitored systems

These systems are often referred to as ‘audible only’, or sometimes ‘locally signalled’, systems as their activation is usually only indicated by the activation of an audible warning device, e.g. a siren, located on the outside of the premises. Response to such systems relies on someone nearby both hearing the alarm and then taking suitable action to investigate its cause or alert others to the activation.

In any event, a telephoned (999) request for police attendance will only be met if the caller can persuade the police that some evidence of criminal activity exists, i.e. the caller can say more than “I can hear an alarm operating”.


Unmonitored systems are typically used at lower risk homes (those without significant amounts of contents/valuables) and which, for a potential response, have other homes adjacent.

Monitored systems

These systems are often referred to as ‘remote signalling’, or sometimes ‘remote monitored’, systems as, in addition to having a site warning device, an alarm transmission system (ATS) product is used to transmit alarm signals to a continuously manned alarm receiving centre (ARC).

The ARC will hold suitable details of the system, the premises and its nominated keyholders – who may be a commercial response company (a company providing alarm response in return for a fee) and/or private individuals, e.g. employees, neighbours, friends, etc.

The installers of such systems conforming to police rules and the applicable standards are entitled to request a police unique reference number (URN).  The award of a URN allows the ARC to directly contact the police force’s control room and request an immediate response to alarm activations justifying police attendance.


Insurers requiring a monitored system normally expect it to have a URN.

Note that if such systems generate too many false alarms, police response will be curtailed or withdraw – which may affect any related insurance cover.

When an alarm system recording as having a URN notifies an alarm activation to the ARC both the police and the keyholders are contacted immediately.


Monitored systems are typically used at business premises and at higher risk homes (those with significant amounts of contents/valuables).


Discussing your requirements with an alarm company is much easier to do if you have an idea of the broad framework within which they operate, and some of the terminology that may be used. This guidance summarises the key features to be aware of, some insurance perspectives and, in the context of monitored systems, any police requirements.


Where your insurer relies upon the presence of an alarm system, it is likely that a policy ‘alarm condition’ will be applied which, subject to the type of system, may typically require:

  • Installation/maintenance, and any monitoring, to be undertaken by an ‘inspectorate’ listed company
  • a maintenance contract with an ‘inspectorate’ listed company being kept in force
  • the insurer being informed of any changes to the system (including signalling)
  • complete setting of the system when the premises are left unattended
  • alarm operating devices (keys/fobs) or alarm code details not being left on site, or in a site keybox
  • the appointment of suitable persons to act as premises keyholders
  • the insurer being informed of any reduction in, or withdrawal of, police response
  • prompt keyholder attendance if there’s any activation or fault

Always read any such condition that applies to you in full, ensuring you both understand and comply with it. In case of doubt always contact your insurance broker/insurer.


Various British Standards covering the design, installation maintenance and monitoring of intruder alarm systems exist:

  • PD 6662 and BS 8243 – applies to the installed alarm system
  • BS 5979 or BS EN 50518 – applies to the ARC

Adherence to these Standards is vital to obtain a Police URN.


Alarm Inspectorates

Whilst anyone can claim to comply with a British Standard, organisations do exist to enforce such claims. The two inspectorates recognised by the police as providing this function, and which also ensure personnel are suitably trained and Criminal Record Bureau vetted, are:

  • National Security Inspectorate (NSI)
  • Security Systems Alarm Inspection Board (SSAIB).

Inspectorate listing of an alarm company and ARC is vital to obtain a Police URN.

Alarm Companies

Systems should be designed, installed and maintained by an NSI or SSAIB listed company.

Inspectorate listing of an alarm company is vital to obtain a Police URN

Alarm Receiving Centres

Monitored systems should be connected to a NSI or SSAIB listed ARC.

Inspectorate listing of an ARC is vital to obtain a Police URN.


Keyholders, sometimes referred to as ‘first response’, should be appointed to deal with/attend all alarm activations/faults.

To adequately fulfil their role, keyholders need to be suitably trained in use of the system, understand the premises security arrangements and have access to all its alarm protected parts. With safety considerations in mind, it is often prudent to arrange for keyholders to attend in pairs – or perhaps use a commercial response company as well, or instead.

Providing an ARC with telephone contact details of at least two keyholders, each able to reach the premises within 20 minutes of being asked to attend, is vital to obtain a police URN.

Commercial Response

The response personnel used by commercial response companies have to hold Security Industry Authority (SIA) guarding licences. NSI or SSAIB listing of a response company is the best assurance that this is being done, and that other relevant standards are being observed.

Where a commercial response company acts as a keyholder and a police URN is required, its personnel must be able to reach the premises within 20 minutes of being asked to attend.

System Design

To ensure adequate system design, inspectorate listed alarm companies have to carry out a formal security ‘risk assessment’. Amongst other matters, this will help determine an appropriate system ‘grade’, the extent and nature of the deployed detection devices, the intended response (a police response normally) and the performance of the alarm transmission system.

System Grade

PD 6662 (in effect) requires all systems, and the equipment used within them, to meet a particular security grade 1 – 4 (4 being the highest), the grades most often required being grade 2 and grade 3.  Unmonitored systems, i.e. those warning with a local audible device only and no connection to an ARC, slot-in as one of the options within grade 2, namely grade 2E.  Insurers disregard grade 1 which provides very low security and very rarely call for grade 4 as there is little equipment on the market that meets its high security requirements.


Insurers typically regard the suitability of these system grades as being:

·        grade 2E – suitable for lower risk homes

·        grade 2 – suitable for higher risk homes and lower risk commercial premises

·        grade 3 – suitable for high risk homes and most commercial premises

A key difference between grade 2 and 3 systems is that in grade 3 systems, any movement detectors have to report ‘masking’ to users when they set the system. Masking is a tactic used by many criminals to deliberately impair the function of movement detectors, by covering (masking) them with sticky tape or hairspray. The aim is to prevent operation of the detectors during a subsequent break in, and is most typically a risk at premises open to the public where unnoticed access to detectors is possible, e.g. retail or leisure premises.

A PD 6662, conforming system, at grades 2, 3 or 4, is vital to obtain a police URN.


System design should ensure that intruders are detected as soon as they enter premises, or at least as soon as they approach or enter areas within it in which ‘target items’ (items of attraction to criminals), are located or concentrated. Various types of detection device exist, those most commonly used being magnetic door contacts (which detect opening of a door), and sensors which detect movement (movement detectors).

If a police URN is held, the police will only attend if a ‘confirmed’ activation is generated – see below.

Hold-up devices

Various push button devices can be used to indicate that a robbery is underway. These are most often used in monitored systems, and may also be used conjunction with other devices, e.g. cameras and microphones, to help an ARC provide ‘confirmation’ of a robbery.


If a police URN is held, the police will initially respond to ‘unconfirmed’ hold up alarms – but if too many false alarms occur an upgrade to provide ‘confirmation’ may be required.


BS 8243 sets out the rules for ‘confirmation’, a methodology that aims to avoid false alarms generated by monitored systems being passed to the police.

Confirmation can be achieved in various ways, for example by use of detection devices plus microphones (‘audio’ confirmation) or cameras (‘visual’ confirmation) but the most commonly used method is called ‘sequential’ confirmation. Simply put, this requires two alarm activations to be received at the ARC, within defined periods of time, before they can ask the police to attend. If only one activation is received, it is referred to as an ‘unconfirmed’ activation.  In these circumstances only keyholders will be notified and, depending on the wording of the insurer’s policy condition, may be required to attend the premises and investigate the cause of the activation.


BS 8243 contains various options for how systems may be unset by users, each of which has an impact on the ability of the system to generate a ‘confirmed’ activation should intruders force entry via the alarm user’s designated entry door. To avoid buying a system where intruders could break in and either not quickly, or at all, generate a ‘confirmed’ activation, it is vital to discuss this aspect fully with your alarm company. In general, some form of lock on the entry door that is electronically linked to the alarm system provides the most secure ‘means of unsetting’.

A monitored system able to provide confirmed activations is vital to obtain a police URN.

Alarm Transmission System (ATS)

This is a critical element of a monitored alarm system, being the function that ensures an alarm activation reaches the ARC for a response.  The response will take the form of police attendance if the system has a URN.  At its simplest, a coded message is sent over the telephone system via a single communication channel.  In alarm system jargon, this is referred to as a ‘single path’ ATS.  This is an inexpensive signalling method but its security weakness is that a fault or criminal act will delay or prevent an alarm activation reaching the ARC.  For this reason insurers generally recommend so-called ‘dual path’ ATS.  If one path of a dual path ATS is lost for any reason, subsequent alarm signals can still be transmitted to the ARC via the remaining path.  In addition, if loss of one path is followed shortly after by the loss of the other (with the implication of criminal activity), the ARC is permitted to call for a police response.

Just as with the alarm system itself, the ATS can be specified at different grades.  These grades determine how quickly the ATS notifies the ARC in the event of a fault – important in view of the possibility of criminal interference.  Again, as with the grade of the system itself, it is important to ascertain the insurer’s preferred or required ATS grade before committing to a particular specification.  Insurers usually also require inclusion of a self-powered audible warning device at the premises.


With the ATS often the most vulnerable part of any monitored system, using an ATS that is not dual path and does not have fast fault reporting times, can seriously undermine alarm protection.

A police URN is not dependent upon having a particular type of ATS, but because loss of one signalling path cannot be treated as a ‘confirmed’ activation, use of a dual path ATS is widely regarded as essential in a confirmation system.

Migration to ‘all-IP’ network

At the present time the national ‘analogue’ voice telephone system, often referred to as the ‘PSTN’ (public switched telephone network), is transitioning to a totally ‘digital’ network referred to as ‘all-IP’.  The program is due for completion sometime in 2025.  This is significant for intruder alarm ATS for two reasons above all others.

For one thing, one of the ATS technologies successfully used for years and the mainstay of cost-effective single path ATS for low risks (referred to in the alarm business as a digital communicator or, simply, a ‘Digicom’) will probably not work correctly on the new network.  If you currently have an alarm system that uses this technology it will probably need to be upgraded – typically to an IP + GPRS dual path system.  Your alarm company has responsibility for identifying ATS equipment suitable for your risk and compatible with the new all-IP network and so if you are informed of an early date for your own ‘migration’, but have not heard from the alarm company, you should contact them to establish the position.

Secondly, the 50V electricity supply that the PSTN system currently carries for the benefit of telecoms equipment in the customer’s premises will disappear.  All communication will pass through a router plugged in to the mains supply in your premises.  If the premises suffer a power cut or sabotage the alarm system ATS (and the telephone for that matter) will fail and be out of service until the power is restored.  Consequently, the insurer may require you to purchase a standby power supply unit for the router.  It may be that the alarm company will offer to deal with this on your behalf.

These and other issues arising from the migration will become clearer as the communications providers (BT, Virgin, Talk Talk etc) embark on the roll-out programme.  If in doubt contact your broker or insurer.

Sources of further information

To find an inspectorate listed alarm company based in your area, please contact:

  • National Security Inspectorate: (01628 637512) or visit
  • Security Systems and Alarm Inspection Board: Tel 0191 296 3242 or visit

BIBA has provided this guide in conjunction with the RISCAuthority, a body representing most UK property insurers. RISCAuthority produces a wide range of technical guidance documents on a variety of property protection topics, all of which can be downloaded free of charge at

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