A move to use facial recognition software in three north London supermarkets has been condemned as "Orwellian surveillance".
Sainsbury's announced last week that five London stores would start using the technology in a bid to combat a rise in shoplifting and abuse towards staff.
The rollout comes after a September trial in two Sainsbury's stores saw a "seismic" drop in thefts.
According to the supermarket giant there was a 46 per cent reduction in theft, aggression and antisocial behaviour with 92pc of offenders not returning - "meaning fewer frightening moments for colleagues and a more reassuring experience for customers".
But civil liberties campaigners Big Brother Watch have slammed what they call "Orwellian technology" which is also being rolled out at Sainsbury's stores in Ladbroke Grove, Dalston, Elephant and Castle, and Whitechapel.
"By treating shoppers like a rogue’s gallery to be monitored and surveilled, Sainsbury’s makes the UK a democratic outlier," said legal and policy officer Jasleen Chaggar.
"The government must follow Europe and ban the use of facial recognition against the general public."
When the technology was being trialled in south London this autumn the campaign group's Senior Advocacy Officer Madeleine Stone said: “Sainsbury’s decision to trial Orwellian facial recognition technology in its shops is deeply disproportionate and chilling. Facial recognition surveillance turns shoppers into suspects, with devastating consequences for people’s lives when it inevitably makes mistakes."
The live 'Facewatch' system uses high definition cameras to capture shoppers' faces - then compares them against a database of known offenders using AI.
It will then send an alert to the store manager if it gets a match.
Sainsbury's say clear signage will go up in stores about the system, which has a 99.98pc accuracy rate, with alerts reviewed by trained staff.
It says the system will only catch those who have previously shown violent, aggressive or criminal behaviour rather than everyday shoppers - and if the system doesn't recognise someone, the image is deleted instantly.
But one commented on the Big Brother Watch Facebook page: "After being wrongly accused of being a criminal by a Budgens store who have ‘FaceWatch’, I won’t go in any shop with FRC.
"Best thing is to boycott the hell out of these shops. It’s a blatant abuse of our freedoms."
While another wrote: "All shops are private and can dictate the terms and conditions they wish to operate under providing that they operate within current law. By entering a shop you accept their terms and conditions."
