Retail giants Boots and Tesco have been accused of endangering lives to protect stock after an investigation revealed firefighters are repeatedly called out by their burglar alarms.

New London Fire Brigade (LFB) figures obtained by the Ham&High reveal that “smoke bomb” security devices are setting off fire alarms time and again – causing fire crews to attend even though there is no blaze.

The systems, which emit a cloud of white smoke to disorientate thieves and obscure their vision, led to 50 false alarms in Camden from April 2010 to April 2013 and dozens more in Haringey and Barnet.

Boots and Tesco stores in Hampstead and Highgate were among the worst offenders, although other shops, offices, theatres and banks were also responsible for unnecessary call outs.

Camden Council’s safety chief, Cllr Adbul Hai, said: “I’m just astonished. These shops have to take some sort of responsibility for putting the safety of the public first.

“It’s a gross misuse of vital public resources. What if there’s a genuine fire they could be responding to?

“Those 10 or 15 minutes could be the difference between death and life.”

The news comes as the stretched fire service faces £45million in cuts which could see 12 stations closed, including Belsize fire station, 18 engines taken out of operation and 520 staff axed.

The figures were released to the Ham&High under a Freedom of Information request which followed the latest incident earlier this month at Boots, Hampstead High Street, Hampstead – which it has emerged was the third at the same store since March 2011.

Two fire crews rushed to the shop after the smoke device was accidentally set off by staff.

Hampstead Town councillor Chris Knight, who witnessed the commotion, said: “It’s potentially putting lives in danger to protect their own stock.

“These shops need to be taking other measures and leaving the fire brigade to protect people, not empty shops.”

The smoke systems at Boots branches in Golders Green and Holborn also prompted false alarms. Meanwhile, there were six calls in as many months to Tesco Express, in Swain’s Lane, Highgate, in 2010, and cases at Tesco stores in Camden Town and Kentish Town.

The 50 Camden incidents cost the brigade an estimated £14,500. In most, the fire alarm was triggered automatically by smoke from the anti-burglar system. Across London, there were 836 incidents in the three-year period, leaving the brigade with a bill of nearly £250,000.

A spokesman for the LFB said members of the public should not be deterred from raising the alarm. He said: “Where the smoke security systems has triggered the smoke alarm system, those false alarms are often as a result of poor management or maintenance.”

A Boots spokesman said: “Smoke cloaks have been identified as an effective deterrent against intruders. The failure rate of this system is low and we have a full and comprehensive maintenance contract to ensure that remains the case.”

Tesco said it fully complied with all design standards and engages with local authorities to make sure that they work as effectively as possible.