British Transport Police invested more than £320,000 in a six-month facial recognition trial that scanned over 500,000 commuters at London railway stations, yet produced no useful results. The system generated just one alert, which proved to be a false positive, meaning no matches were found and no arrests resulted from the technology. Despite this demonstrable failure, BTP has extended the trial until November and expanded it to include the London Underground, prompting concerns from privacy advocates about wasted public resources and intrusive surveillance of innocent passengers.

The pilot consumed nearly 100 hours of officers' time and used NEC's NeoFace M40 technology to compare captured faces against police watchlists. BTP maintains the system immediately deletes biometric data from those not on a watchlist and targets crime hotspots where officers believe "high harm offenders" are likely to appear. However, civil liberties groups including Liberty, Big Brother Watch and Privacy International argue the trial demonstrates how invasive the technology is, processing thousands of innocent people's highly sensitive facial data without their knowledge, and they emphasise there is currently no specific legal framework regulating such deployments.