British Transport Police (BTP) have spent more than £320k and almost 100 hours of officers’ time on a six-month trial of live facial recognition (LFR) technology in London’s railway stations – yielding just one incorrect face match and no arrests.

The surveillance tech scans passersby and alerts authorities if it recognises someone on a watchlist. It is supposed to help catch people accused of crimes or who breach court orders.

But a freedom of information request by Liberty Investigates, shared with the Guardian in September, revealed that after scanning more than half a million faces between February and July, the tech only sent one suspect alert, and that turned out to be a false positive.

Despite this failure, Transport for London (TfL) has given permission for the technology to be expanded across London Underground stations too.

Well, at least there aren't dozens of false positives and people getting arrested or shot, like with Flock in America.