Police facial recognition software could be wrong in the vast majority of cases, an independent report has revealed.

Facial recognition technology, currently being trialled by the Met Police, compares live images of the public with a database of wanted people. It then uses biometric mapping to suggest matches with the watchlist.

Trials of the new tech were carried out at Notting Hill Carnival in 2016 and 2017, and between June last year and February this year at locations across the capital.

But in tests observed by researchers from the University of Essex, only eight of 42 total matches were verified as correct – suggesting there were errors in as much as 81 per cent of cases.

During trials – in Romford, Stratford and Soho –  16 of the 42 suggested matches were rejected straight away by officers reviewing the software.

In the remaining 26 cases, police on the ground tried to stop the person – but of 22 people successfully stopped, only eight matched the identity suggested by the software.

This means the technology was successful in just 19 per cent of cases – fewer than one in five.

Green assembly member Sian Berry, who sits on City Hall’s police and crime committee, said the technology threatened Londoners’ civil liberties.

She said: “This report shows how wrong it was for Met to rush this technology onto our streets. It’s clear the police should never have pressed ahead with facial recognition trials without a legal mandate.”

But Conservative member Tony Arbour, also a police and crime committee member, said despite flaws the technology was hugely important.

He said: “Facial recognition technology has the potential to revolutionise how the Metropolitan Police catches criminals but it will require time to get it right.

“The trials have shown that there are problems to be ironed out but that’s why the Met carries out these tests.”

Deputy Assistant Commissioner Duncan Ball said he was “disappointed with the negative and unbalanced tone” of the Essex University report.

He said: “The public would expect the Met Police to use all available and proportionate means to catch violent offenders and it is right that we trial emerging technology that could help us to do so.

He added: “While this technology can be used to assist us, it does not by any means replace the role of a police officer.”