London police could face a court battle over their decision to use live facial recognition on the general public.
The force announced on Friday that it will start using cameras to scan passersby on London streets.
But now Green peer Baroness Jenny Jones and civil liberties group Big Brother Watch plan to mount a legal challenge against the Home Office and the Metropolitan Police.
Live facial recognition will scour video footage for matches with mugshots of criminals wanted for serious crimes like child sexual exploitation or knife and gun violence.
The technology codes facial features as a series of measurements, calculating tiny details like the depth of eye sockets and the width between nostrils. This should allow it to identify the same person in live CCTV footage.
But a highly critical report by Essex University, commissioned by the Met last year, said trials in London were only 19 per cent accurate, and the technology could flout human rights.
Now Baroness Jones – a former Deputy Mayor of London under Ken Livingstone – and Big Brother Watch have instructed their lawyers to restart an existing legal challenge.
The Green peer – whose photo was held on a ‘domestic extremism’ register while she sat on a board overseeing the Met and ran for Mayor of London – said she feared that public safeguards were “failing to keep up with the modern world”.
She said: ”With the roll out of facial recognition across London we have major expansion in the use of biometric data by the police, but without a public debate about what regulations and safeguards are needed.
“There will be inevitable mistakes and errors with using this technology and innocent people will suffer the consequences.”
She added: “It is essential that the government call for a moratorium on the use of this technology by both the private and state sectors, so we can put a modern system of regulations into place.”
Big Brother Watch and the Baroness first raised concerns during trials of facial recongition technology in 2018, but paused their legal action when the Essex report criticised the technology.
A spokesperson for Big Brother Watch said they assumed the Met “wouldn’t dream” of going ahead with facial recognition after the “extremely damning” report.
The spokesperson said Big Brother watch was now “urgently considering options” and would mount a “robust challenge” to the Met’s decision.
Met Assistant Commissioner Nick Ephgrave, said the new technology would be “vital” to tackle violence in the capital.
He said: “We all want to live and work in a city which is safe: the public rightly expect us to use widely available technology to stop criminals.
“Equally I have to be sure that we have the right safeguards and transparency in place to ensure that we protect people’s privacy and human rights.
“I believe our careful and considered deployment of live facial recognition strikes that balance.”
The use of facial recognition by Welsh Police was challenged in the High Court last year – the court ruled in favour of the police, but an appeal will be heard in June.
The Home Office was approached for comment.