Cameras which can recognise and identify people’s faces have been introduced the 67-acre area of King’s Cross.
It is not confirmed how many facial recognition cameras are in use – or how long they have been active.
And further plans are being drawn up to introduce the high tech cameras into the 97-acre area of Canary Wharf.
Both areas have a huge amount of footfall, with hundreds of thousands of people passing through every day potentially being monitored by the cameras.
Data protection laws in the UK mean that data on faces cannot be compiled without consent of people, reports the FT.
“The privatisation of public spaces in London raises interesting legal questions”
King’s Cross is an area that contains Google’s base in the UK, plenty of shops and Central Saint Martins college from the University of the Arts London.
Canary Wharf includes companies such as Barclays, HSBC, and your Daily Star.
The group which owns the offices and public spaces in the docklands metropolis is reportedly “actively speaking” with facial recognition firms.
Some 140,000 city workers go to Canary Wharf every day, and there are estimated to 49 million visits made every year.
Stephanie Hare, an independent researcher of facial recognition technologies in the UK, said: “What’s really worrying is for any worker who doesn’t want to participate.
“This is essentially a geofenced experiment, so I don’t see how anybody could opt out of it.
“You can’t opt out of walking around London, or working there.
“How do they defend it when this technology is the subject of legal action and MPs are calling for a moratorium on it?”
Security sources claimed the facial recognition cameras would not operate continuously – but instead be targeted for specific purposes.
Canary Wharf already operates at least 1,750 CCTV cameras, as well as an automatic licence plate recognition system to track vehicles in the area.
London also has 420,000 cameras around the city – with are being upgraded to be connected to the internet with better image resolution.
Shops such as Sainsbury’s, Tesco and Marks Spencer also have facial recognition cameras around Britain.
Pete Fussey, a criminologist at the University of Essex, said: “The private sector uses of facial recognition need a lot of attention because there is less regulation and governance here.
“The privatisation of public spaces in London raises interesting legal questions.”
Two police forces in Britain – the Met Police and South Wales Police – have also trialled facial recognition cameras.
Liberty Human Rights, a privacy advocacy group, said: “Facial recognition is a dangerously intrusive and discriminatory technology that destroys our privacy rights and forces people to change their behaviour.”