In response to the recent riots across England, David Cameron has said the UK government will discuss with police, intelligence agencies and the technology industry "whether it would be right to stop people communicating via [social networking] websites and services when we know they are plotting violence, disorder and criminality".

"Everyone watching these horrific actions will be stuck by how they were organised via social media," the Prime Minister said in the House of Commons today. "Free flow of information can be used for good. But it can also be used for ill. And when people are using social media for violence we need to stop them."

Cameron’s remarks echo calls from Tottenham MP David Lammy and Streatham MP Chuka Umunna for temporary blocks on BlackBerry Messenger, a private instant messaging service reported to have been used by rioters to co-ordinate unrest. BBM "is one of the reasons why unsophisticated criminals are outfoxing an otherwise sophisticated police force," said Lammy.

That position was strongly opposed by Conservative MP and former Army officer Patrick Mercer as he spoke on the BBC’s Today programme on Tuesday morning. "If we start interfering with things like BlackBerry, then we start interfering very seriously and, to my mind, quite wrongly with our liberties," Mercer said. "We mustn’t do that. That is actually giving in to the thugs."

Any proposal to block social networks during civil disorder could prove an unpopular policy. Mobile telecommunications provider Vodafone was heavily criticised when it blocked Internet access to its customers in Egypt during the revolution on the request of the government.