Police in London are testing face recognition in central London on Monday and Tuesday this week as part of an ongoing series of trials of the technology.
The Metropolitan Police said officers would be plainly visible and would invite passersby to have their faces scanned, rather than doing so covertly.
The trials are to take place for roughly eight hours per day in Soho, Picadilly Circus and Leicester Square.
Trials are to be “used overtly with a clear uniformed presence” with leaflets being distributed to the public, police said.
The Met added that those who do not wish to be scanned “will not be viewed as suspicious by police officers”.
Privacy group Big Brother Watch, which is campaigning against the technology, said such systems were “authoritarian, dangerous and lawless”.
“Monitoring innocent people in public is a breach of fundamental rights to privacy and freedom of speech and assembly,” the group said.
In the UK the tech has previously been trialled at a Champions League final in Cardiff amongst other locations.
Police say it can be used to identify people who are wanted by the justice system, but Big Brother Watch said it has returned a “staggering” proportion of false positives.
The UK Information Commissioner’s Office (ICO) began a probe into police use of face recognition in November, with information commissioner Elizabeth Denham saying the technology could be “particularly intrusive” inspite of its “significant public safety benefits”.
Big Brother Watch said on Twitter it was “fighting this for all the people who don’t want to be walking ID cards in a surveilled nation”.
European Parliament votes to adopt Digital Markets Act and Digital Services Act, but campaigners warn…