London facial recognition trial had one false alert

A six-month British Transport Police trial of live facial recognition at London railway stations scanned more than 500,000 faces and produced one false watchlist alert, with no arrests directly resulting from the technology, according to figures disclosed through a Freedom of Information request. The trial cost £320,786 for equipment hire and police staffing. The deployments ran from February through July and took place 18 times, using nearly 100 hours of police time. The single alert was an incorrect identification. The figures were reported from a document obtained by Liberty Investigates; they describe the trial’s recorded performance, rather than arrests made by officers for other reasons while the technology was deployed. British Transport Police said officers made arrests during deployments for offences including assault, theft and public-order offences, and located people wanted by courts or other police forces. The force said those actions were not directly caused by facial-recognition alerts and were therefore excluded from its performance data. The force extended the pilot for a further four months and expanded deployments to selected London Underground stations.