£320,000 London Facial Recognition Trial at Railway Stations Yields One False Alert, No Arrests

A six-month trial of live facial recognition (LFR) technology in London's railway stations, which cost more than £320,000 and nearly 100 hours of police officers' time, resulted in just one match against a watchlist of suspects — and that match was incorrect. No arrests were made as a direct result of the system's alerts.

More than half a million faces were scanned between February and July this year at some of the capital's busiest transport hubs during the trial, run by British Transport Police (BTP) with the aim of helping catch offenders and people breaching court orders.

A freedom of information document obtained by Liberty Investigates and shared with the Guardian shows that equipment hire and police staffing for the 18 deployments across the trial cost £320,786 in total. The single alert generated against the watchlist during that period turned out to be a false positive.

Last month BTP announced it was extending the trial for a further four months and expanding deployments to include London Underground stations. The force said that since the extension began, there had been three confirmed positive alerts involving people who were subsequently found to be complying with sexual harm prevention orders or other court-imposed conditions.

When Transport for London announced its support for the extended trial, it said the technology would "target and identify people on police watchlists at key stations chosen for maximum impact" and would "specifically tackle violence against women and girls, whose travel behaviours are shaped by experiences of sexual harassment and sexual offences."

Fraser Sampson, a former biometrics and surveillance camera commissioner for the UK, said police needed to demonstrate that use of the technology was proportionate. "There are many variables and all need to align: the choice of location, times of day, make-up of the watchlist and likelihood of people being present, and many more," he said.

Sampson, who is now a non-executive director of Facewatch, a company that operates facial recognition systems in shops, drew a distinction between retail and policing uses. "We know the technology works, but using it in supermarkets to deter shoplifters and prevent attacks on staff is very different from deploying it on a public transport network. Success in a shop means no such people coming in. Success for the police trying to catch people means people being caught. In that respect, the trial doesn't appear to have been very fruitful."

He added that the system only flags individuals already on a watchlist. "If you're not on a watchlist, the live FRT cameras do not 'see' you and they don't retain your image in the same way as CCTV cameras. However, they are processing special category personal data, and the technology must be used in a way that is appropriate, proportionate and necessary. It's for the police to show how any deployment meets those criteria and — as the Information Commissioner's Office has recently reported — for their oversight boards to hold them firmly to account in doing so."

More than half of police forces in England and Wales have now deployed live facial recognition on British streets, according to analysis by Liberty Investigates. The Metropolitan Police and the London mayor's office announced this summer that fixed cameras using the technology would be installed in the capital's West End, and the mayor, Sadiq Khan, has confirmed it will be used on the newly pedestrianised Oxford Street.

A recent report from parliament's joint committee on human rights, which called for a new law to address the risks artificial intelligence poses to human rights, identified the rollout of live facial recognition as "a particularly clear example of risk."

Bell Ribeiro-Addy, the Labour MP for Clapham and Brixton Hill, said: "Live facial recognition technologies are a serious invasion of our privacy. The government should be suspending their rollout until there are stronger safeguards in place, including a proper legal framework."

A BTP spokesperson said the pilot was launched "to understand how the technology could most effectively support the identification of wanted offenders and individuals who may pose a risk to passengers and staff." The force said officers had made a number of associated arrests during the trial period — including for assault, theft, possession of an offensive weapon, breach of a criminal behaviour order and public order offences, as well as locating individuals wanted by the courts and other police forces — but that these did not result directly from LFR alerts and so were not counted within the technology's performance data.

"Throughout the pilot, we have continued to refine how the capability is deployed within the railway environment," the spokesperson said, citing developments to deployment locations, operating procedures, equipment and watchlist construction. "Watchlist growth has been deliberate, controlled and aligned to BTP policy. We began with a more limited watchlist whilst ensuring data quality, governance and safeguarding arrangements were robust."