Civil rights campaigners are condemning a move by South Wales Police to trial a facial recognition app on officers' mobile phones.

The force is already facing a legal challenge to the technology's use. It says the app only be used when both necessary and proportionate and it'll be closely monitored.

Fifty officers will be involved in the three month trial.

Following the rollout of the technology in 2017, the force admitted it wrongly matched more than 2,000 people as possible criminals at the Champions League Final in Cardiff.

South Wales Police said at the time "no facial recognition system is 100% accurate" and the accuracy of the system has continued to improve.

Detective Chief Constable Richard Lewis of South Wales Police said the app will help officers access "instant actionable data". He said police officers will only be using the new technology where it is a"necessary and proportionate" and the trial will be "closely monitored.

When dealing with a person of interest during their patrols in our communities, officers will be able to access instant, actionable data, allowing to them to identify whether the person stopped is, or is not, the person they need to speak to, without having to return to a police station. Deputy Chief Constable Richard Lewis

Facial recognition technology is being trialled in South Wales and London. Credit: ITV News

Civil Rights group Liberty argues the technology is intrusive.

Hannah Couchman from the organisation called the move "shameful" and a "gross abuse of power"

"This technology destroys our anonymity in public spaces, chilling our ability to take part in protests and increasing state control over every one of us", she added.