I read recently that figure was done by extrapolating the cameras visible in one section of a street in London to the UK as a whole. I've had a look and can't find that particular link.
> Britain has a CCTV camera for every 11 people, a security industry report disclosed, as privacy campaigners criticised the growth of the “surveillance state”.
> The survey’s maximum estimate works out at one for every 11 people in the UK, although the BSIA said the most likely figure was 4.9 million cameras in total, or one for every 14 people.
> “Because there is no single reliable source of data no number can ever be held as truly accurate however the middle of our range suggests that there are around five million cameras.”
> The Claim : > "A CCTV camera for every 14 citizens." David Davis, resignation statement, 12 June 2008
> The basis comes from a survey of the number of CCTV cameras in two busy south London streets, Putney High Street and Upper Richmond Road.
> The researchers sampled 211 "premises" - banks, estate agents, pubs, shops and office blocks - and found that 41 per cent had CCTV systems, with an average of 4.1 cameras per system.
> By assuming this is "broadly representative" of CCTV coverage across the whole of London, the authors estimate that 41 per cent, or 102,910, of the 251,000 VAT-registered businesses registered in London would have a CCTV system. Multiply this by 4.1 and there would be 421,931 cameras.
> Bingo - there's the claim, but we've got to it based on two London streets, multiplied out to reflect the whole of London, and then multiplied again to reflect the whole country.
> When counting cameras, he reckons it's also important to look at what exactly they are monitoring. "Some may be in a private business such as a corner shop, some may be one camera outside a pub that isn't actually monitored, something like a building society may have more cameras 'back of house' which are not actually on the public," he said.
> http://www.telegraph.co.uk/technology/10172298/One-surveilla...
> Britain has a CCTV camera for every 11 people, a security industry report disclosed, as privacy campaigners criticised the growth of the “surveillance state”.
> The survey’s maximum estimate works out at one for every 11 people in the UK, although the BSIA said the most likely figure was 4.9 million cameras in total, or one for every 14 people.
> “Because there is no single reliable source of data no number can ever be held as truly accurate however the middle of our range suggests that there are around five million cameras.”
and also from 2008 :-
> http://www.channel4.com/news/articles/society/factcheck+how+...
> The Claim : > "A CCTV camera for every 14 citizens." David Davis, resignation statement, 12 June 2008
> The basis comes from a survey of the number of CCTV cameras in two busy south London streets, Putney High Street and Upper Richmond Road.
> The researchers sampled 211 "premises" - banks, estate agents, pubs, shops and office blocks - and found that 41 per cent had CCTV systems, with an average of 4.1 cameras per system.
> By assuming this is "broadly representative" of CCTV coverage across the whole of London, the authors estimate that 41 per cent, or 102,910, of the 251,000 VAT-registered businesses registered in London would have a CCTV system. Multiply this by 4.1 and there would be 421,931 cameras.
> Bingo - there's the claim, but we've got to it based on two London streets, multiplied out to reflect the whole of London, and then multiplied again to reflect the whole country.
> When counting cameras, he reckons it's also important to look at what exactly they are monitoring. "Some may be in a private business such as a corner shop, some may be one camera outside a pub that isn't actually monitored, something like a building society may have more cameras 'back of house' which are not actually on the public," he said.