London is considered the most spied-on city in the world, courtesy of its ubiquitous CCTV cameras, purportedly there to reduce crime. But according to a recent report, there's been little or no change in London's crime rates since they were more widely installed in the mid 1980s.

Privacy activists are worried that Britain will become the bleak totalitarian society George Orwell painted in his classic novel "1984," where citizens were spied on and personal freedom sacrificed for the benefit of an all-powerful state.

"We are sleepwalking into a surveillance society where we're watched from control rooms by anonymous people, says Emma Carr of the BBW. "The worrying thing is that we don't actually know how many CCTV cameras there are out there."

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In the report released this week, civil rights group Big Brother Watch revealed that local councils spent £515 million (about $807 million) on new cameras over the past four years, the equivalent of 4,121 police officers. Birmingham, England's second most populous city, has spent the most: £14.3 million ($22 million) over past four years, followed by Westminster at £11.8 million ($18.5 million), and Leeds at £8.7 million ($13.6 million).

BBW estimates there are now some 51,000 police-run cameras watching British citizens in urban areas, not including private cameras or cameras situated in other public buildings like train stations or bus depots.

A common figure cited is a total 4.2 million cameras across the Britain based on a working paper published in 2002, by academics Michael McCahill and Clive Norris but research last year by Cheshire Police puts the figure closer to 1.85 million.

But Ms. Carr says that without official registrations and research it is impossible to calculate.

The civil rights group Liberty estimates that the average Londoner is captured on camera around 300 times a day while BBW claims Britain has 20 percent of the world's CCTV cameras and only 1 percent of the world's population.

There is a perception that the cameras reduce the crime rate, but there is no evidence for that, say activists. "The Met police have said that in 2008, only one crime was solved for every 1,000 CCTV cameras," says Carr.

Charlie Masson Smith, a spokesman for Wandsworth Council, which covers the south London suburb of Balham, disagrees.

"They do help the police solve crime – in 2010, 841 cases in Wandsworth were brought to court using CCTV camera footage. But it's not just crime, they can be used for traffic congestion or other ways like the time they helped rescue someone from the Thames when they had fallen in the river. We think it is money well spent."

He says cameras are only located in mostly urban areas and where residents or businessmen have requested them. His local authority has 1,158 CCTV cameras and spent £4.7 million ($ 7.4 million) over the past four years making it No. 8 on the list of big spenders.

"Most cameras are in shopping areas or near to Tube stations, we don't put them in Acacia Avenue," he says. "We try and strike a balance with civil liberties but a lot of the time we are reacting to what people are wanting.

There are nearly 70 cameras on display on lampposts, sides of buildings and in the underground and mainline and train stations in a half-mile stretch of main road in Balham.

To be sure, at least some residents here don't seem to notice or mind.