According to Norwich Union Risk Services, 25 per cent of businesses may have inappropriate alarm systems.
The data comes from NURS research that shows that although 75 per cent of businesses had some kind of alarm signalling, 25 per cent had a 'bells only' alarm.
Richard Underwood, property security specialist for NURS, said: "Opting for an alarm system from a supplier who is registered with the NSI or the SSAIB will help ensure businesses receive a thorough assessment of their needs, providing significant benefits to the business".
"These accredited suppliers are the sole providers of 'Type A' alarms, as defined by strict criteria set by ACPO and ACPO in Scotland. Such alarms are the only ones eligible for a unique reference number, which in turn qualifies them for a police response via an alarm signal handled by a recognised alarm receiving centre.
"Type B systems, most typically known as a 'bells only' alarm, are not issued with a URN and police will not respond unless there is some kind of on-site verification from the public, which in reality might be too late – rendering them less effective. Intruder alarms are an essential part of a business continuity plan and businesses must ensure that a security alarm is fit for purpose."