Americans in favour of CCTV cameras in public places Some 78 per cent of people in the US said that having more surveillance cameras, which remain relatively rare on American streets, was "a good idea," the CBS News/New York Times survey found. While authorities in London have access to more than 91,000 CCTV cameras, according to the pressure group Big Brother Watch, their counterparts in Boston are believed to oversee only a few hundred. "Surveillance cameras don't prevent terrorist attacks," said Abdi Soltani, an executive director of the American Civil Liberties Union. They didn't prevent last week's attack in Boston and they didn't prevent the 2005 attacks in London, one of the most heavily watched cities in the world. We must be incredibly careful that we don't sacrifice our liberty for the illusion of increased safety. Despite the country's vigorously defended constitutional right to free speech, Americans also said that they were in favour of censorship as part of US efforts to prevent future attacks. Two-thirds of respondents to the poll said that information on how to make explosives should not be allowed on the internet, compared to 30 per cent who said it should be permitted. Dzhokhar Tsarnaev, the surviving Boston bomber, has reportedly told investigators that he and his brother Tamerlan researched bomb-making in Inspire, al-Qaeda's English language online magazine.