When Ian Clayton, a retired health and safety professional from Chester, popped into Home Bargains one February lunchtime, he was suddenly approached by a stern-looking member of staff. “Excuse me, can you please put everything down and leave the shop now?” she said. Clayton recalled how he was stunned, and it was only as he was briskly walked past the tills towards the exit that he stopped to ask what he had done. “You’ve come up on our system called Facewatch as a shoplifter,” came the reply. “There’s a poster in the window.” With that, he was left outside the shop alone, with a QR code to scan and no idea what had happened. He is one of a number of people who have spoken to the Guardian after being falsely identified as a thief by shops using Facewatch, a live facial recognition system being rolled out across the UK to clamp down on retail crime. The company’s website claims that its system has a 99.98% accuracy rate and that last month it sent 50,288 alerts of “known offenders” to shops including B&M, Home Bargains, Sports Direct, Farm Foods and Spar, which all now use the software. But those who have been wrongly identified and forced to leave shops, either via the technology itself or human error, say they were given no support, and did not know how to complain about their treatment or prove their innocence. Clayton, 67, said that after he was ejected from Home Bargains he tried calling a phone number on a Facewatch poster, and was sent through to a message saying the company did not take calls and he had to send an email instead. He was only able to get answers after submitting a subject access request – a formal request under data protection