An old Rely-A-Bell burglar alarm box on a wall in the Hidden Lane in Glasgow. First created around 1904, Rely-A-Bell alarms were initially manufactured by the London ironmonger Thomas Gunn. It was spun off into its own company, the Rely-a-Bell Burglar and Fire Alarm Company Limited, in 1921. It's believed to be the oldest burglar alarm company in the UK.

