The Metropolitan police used the King's Coronation to gather thousands of people's biometric data, against their permission, or even knowledge.
The Coronation was seen as the perfect opportunity for a mass data-gathering operation. All under the pretext of security the Artificial Intelligence system is able to record, log, and categorize hundreds of people simultaneously, something not achievable prior to the new system.
The Metropolitan police has been accused of using the coronation to stage the biggest live facial recognition operation in British history.
The force said on Wednesday it intended to use the controversial technology, which scans faces and matches them against a list of people police want for alleged crimes and could identify convicted terrorists mingling in the crowds.
Hundreds of thousands of people are expected on the streets on Saturday as King Charles is crowned at Westminster Abbey, after a procession through central London, with a massive security operation in place.
The announcement came as police were given new powers to crack down on protest, enacted into law by government just days before the high-profile ceremonial event.
Campaigners fear the face-scanning technology could be used against protesters, and that police have done so before.
"Police normally require a legal basis to check your identity or ask for your biometric data. But facial recognition surveillance introduces arbitrary identity checks to our society, turning us into walking ID cards subject to high-tech police lineups. This poses a major threat to our civil liberties and democratic rights – we must resist it." - Big Brother Watch.