Shoppers push their carts through the aisles of Tesco grocery store in Brixton, South London.
London: British supermarket chain Tesco is installing hundreds of hi-tech screens that scan the faces of shoppers as they queue at tills to detect their age and sex for advertisers.
The supermarket has signed a deal with Amscreen, a digital signage company owned by Lord Alan Sugar, in a move which drew concern from privacy campaigners about the growing use of "invasive" technology in shops.
The "OptimEyes" system will be installed on the forecourts of 450 Tesco petrol stations, which serve millions of customers a week.
Lord Alan Sugar.
Cameras built into a digital advertising display above the tills identify whether a customer is male or female, estimate their age and judge how long they look at the advertisement displayed.
The "real-time" data is fed through to advertisers to give them some idea of how effective their campaigns are and to enable them to tailor advertisements to certain times of the day.
The scenario is reminiscent of one in Minority Report, the 2002 science fiction film in which actor Tom Cruise's character is bombarded with personalised advertisements as he walks down the street, after sensors detect him by scanning his eyes.
Simon Sugar, Lord Sugar's son and the chief executive of Amscreen, told The Grocer magazine: "Yes, it's like something out of Minority Report, but this could change the face of British retail and our plans are to expand the screens into as many supermarkets as possible."
He insisted that OptimEyes, which was developed in conjunction with a face detection software specialist, does not store images or recognise people, and instead simply "works out gender and sorts customers into one of three age brackets".
Privacy campaigners in Britain said on Sunday that the sharp increase in personal data collection was threatening to spiral out of control. Nick Pickles, of Big Brother Watch, said camera technology was already available that matched scans of people's faces with their pictures on Facebook to tailor special offers to their "likes" on the social media website.
He told London's Daily Telegraph: "People would never accept the police keeping a real-time log of which shops we go in, but this technology can do just that. It is a surveillance state by the shop door."
The technology is already used in forecourts across Britain, but Amscreen claims the deal with Tesco is the biggest of its kind since the system was unveiled earlier this summer.
Peter Cattell, category director for Tesco petrol stations, said the technology would "enhance" its customers' shopping experience.
He said: "The ability to tailor content based on time and location means this can be extremely useful and timely for interacting with our customers."