LONDON, May 22 (Reuters) - Tourists, shoppers and office workers in a busy ⁠London street on an ordinary weekday found themselves part of a digital identity check as live facial recognition cameras scanned faces against a police watchlist.

The operation was an example of a ⁠technology the Metropolitan Police say is transforming policing, helping officers arrest around 2,500 wanted people since the start of 2024, including suspects accused of violent and sexual offences.

Critics, however, say ‌live facial recognition undermines the presumption of innocence underpinning British law by treating every passer-by as a potential suspect.

A court challenge brought by civil liberties campaigners and a community worker who had been wrongly identified failed last month, clearing the way for the technology's expanded use.

In Victoria, central London, on a recent Monday few people appeared concerned by the temporary cameras, a police van and signs warning that live facial recognition was in operation.

Within an hour, the system alerted an officer in the control van to a possible match. Local ​officers approached a man and questioned him briefly before letting him go. Police later said the alert related to court-imposed restrictions ⁠rather than an arrest warrant.