Description:There are more closed-circuit television cameras in Britain than any other country in the world. There are so many that the exact number is not known, but one estimate puts it as high as 4.8 million, roughly one for every 12 people. In London alone, there are half a million CCTV cameras. That number is reliable because a year ago the Metropolitan Police, London's police service, used it when announcing its plans to provide security for the upcoming 2012 Olympics.(1:31)