CCTV cameras that detect potential offenders and then "tail" them are being tested in British shopping centres.
The $14,000 "Bug" is fitted with a ring of eight cameras that gives a panoramic view of a street.
The footage is scanned by sophisticated software which can identify 50 behavior traits that indicate whether somebody is acting or loitering in a suspicious manner.
When a suspect is spotted, a ninth camera automatically locks onto them and follows their movements.
It means town centres can be monitored without the need for human operators to watch screens.
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The device has been tested in Europe for the last 18 months and are due to install the "intelligent" camera system.
Jason Butler, head of CCTV at Luton council, said: "The camera picks up on unusual movement, zooms in on someone and gathers evidence from a face and clothing, acting as a 24-hour operator without someone having to be there.
"We have kids with Asbos telling us they hate the thing because it follows them wherever they go."
But civil liberty campaigners claim the cameras are yet another extension of state surveillance in what is already the world's most spied upon country.
There are 4.2 million CCTV cameras in Britain - a fifth of the world's total.
Earlier this month the Home Office announced plans to extend the use talking CCTV cameras that order passers-by to pick up dropped litter.
Critics say the Bug sounds like a step towards the world depicted in the 2002 science fiction film Minority Report, where Tom Cruise stars as an officer in a police "department of pre-crime" that arrests offenders on the basis of what they are about to do.
Simon Davies, director of Privacy International, said: "We do not know what the psychological impact of this will be on the population."
But Stuart Thompson, managing director of Kent based company Viseum that developed the Bug, said the innocent had nothing to fear from the device.
He said: "It may mistake someone window-shopping for someone loitering, but on every occasion that a crime has been committed the system has always caught evidence."
Several police forces are also considering another intelligent camera attached to unmanned drones that fly stealthily above cities to spy on people below.
The camera can zoom in on and track a single face from 500 feet.
These can then be scanned and matched against a database of known criminals or terror suspects. The camera is fitted to a drone made from lightweight plastics and carbon fibre called the Casper 250, which was originally created for the Israeli army.
It has a wingspan of 8ft and a top speed of more than 50mph, but is powered by an electric engine, making it almost inaudible to those on the ground.
Police believe it could be used to help routine work such as monitoring traffic, demonstrations and marches, and for more sensitive operations such as tracking drug traffickers and terrorists.