Big Brother is watching: the CCTV that talks back

The voice is calm, American and insistent: "Stop, this is a restricted area and your photograph is being taken. It will be sent for processing if you don't leave the area now."

This is not the Pentagon but a green communal area in the centre of a north London estate. Residents yesterday criticised the new talking CCTV camera installed by Camden council in an attempt to prevent anti-social behaviour and drug-dealing as an over-reaction and an attack on civil liberties.

Jim Jepps, who lives on the estate, discovered its use on Saturday night. He said: "What really annoys me is that we have this American Robocop voice telling us that our garden is a restricted area." He disputed the claim that Walker House was a centre of crime and anti-social behaviour. The Home Office's crime-mapping site does not show any crimes at the estate in the last year.

Privacy campaigners say the use of the camera highlights the growing extent of Britain's surveillance society with an estimated 1.85 million CCTV cameras located around the country.

A system of manned talking CCTV cameras which allows operators to publicly shame offenders was extended to 20 boroughs across the country in 2007 by the previous administration after the system was pioneered in Middlesbrough. Cameras were positioned around Middlesbrough's town square and were monitored by staff who pointed out public-order offences. Campaigners claim that one person was scolded for throwing a snowball.

The automated cameras have been used as a cheaper alternative by councils across the country. The Camden camera may be extended to other estates, Roger Robinson, a councillor, said. Mr Robinson said the camera was a response to 10 years of harassment and threats against people living on the estate. "We don't want drug dealing and harassment. People have been known to smash cars and steal motorbikes. We're entitled to do something," he said.

Josie Appleton, director of the Manifesto Club, which campaigns against the hyper-regulation of everyday life, said the case showed the intrusiveness of CCTV cameras. "This makes it more worrying in terms of the implications for civil liberties," she said. Officials at Camden council were not available to comment. In a statement, it said: "We do not want to stop people from enjoying their open spaces, just to make these areas safer for those who use them."