Riots ... a masked man walks past a burning car in Hackney. Credit:Getty Images "And when people are using social media for violence, we need to stop them. So we are working with the police, the intelligence services and industry to look at whether it would be right to stop people communicating via these websites and services when we know they are plotting violence, disorder and criminality." Mr Cameron did not specify whether this would involve shutting down the sites for all people in an affected area or trying to block specific individuals from using the sites. The conservatives seem to have the support of the Labour Party for this proposal, with shadow culture secretary Ivan Lewis telling British media "free speech is central to our democracy but so is public safety and security". Mr Lewis said Labour supported the government’s decision to undertake a review of whether measures are necessary to prevent the abuse of social media by those who organise and participate in criminal activities.

The BlackBerry has been linked to the London riots. Illustration: smh.com.au and agencies Facebook has responded, saying it has already taken steps to remove "credible threats of violence" related to the riots. Tiphereth Gloria, digital and social strategist at GPY&R Sydney, said blaming social networks for the speed and ease of communications and blocking them was the digital equivalent of shooting the messenger. She compared the move to the shutdown of the Egyptian internet in January - an effort to quell the anti-government uprisings. The move was quickly subverted by internet companies such as Twitter which allowed people to phone in to a messaging service with their comments, which were then tweeted out with the #egypt hashtag. "For British politicians to block or attempt to censor social channels, they are exhibiting the same traits as Egypt's totalitarian regime," she said.

"They would do better in funding for more police and using social channels to get their own messages out." Mike Conradi, partner and telecoms specialist at the London law firm DLA Piper, told The Guardian that measures to stop rioters communicating on social media sites would require legislation and threaten free speech. "It would certainly put the UK in a difficult position in terms of talking to authoritarian regimes and trying to convince them not to turn off their networks," he said. Jonathan Crossfield, social media expert and community manager at Ninefold, said that, although rioters used social media, far more people used services such as Twitter to follow events in their neighbourhoods to stay safe, offer help to others in their communities and arrange clean-ups. Social media is also being used to identify the looters via crowd sourcing. For those who have been charged with offences, British police have taken to Twitter to name and shame them.

"Social media is a neutral medium. It has as much capacity to help, inform and advise the general public than it does to aid the rioters," he said. "Politicians and commentators should be careful not to blame the medium but instead look at ways to potentially increase the benefits in such times by using it more effectively, rather than seek to limit its effectiveness. "Block social media and the rioters would switch to SMS or voice calls instead." James Griffin, partner with social media intelligence firm SR7, said he did not believe implementing such a policy would be an issue as the government and intelligence authorities ''have the ability to disrupt services and access to social media''. But he said the political implications of doing so may create more questions and problems than solutions.

"Recently, both the United States Senate and the House of Representatives passed a motion condemning the obstruction of telecommunications during protests in Iran," he said. ''I would argue that the difference here is that whilst one group of people on the other side of the world are fighting for democracy, these people are robbing fashion labels and electronics stores. If the Cameron government has the evidence to show that by limiting access to social media it will stop them from planning violence and criminality then it is an option that they should explore.'' Australia has also discussed controls on social media. State and federal attorneys-general are mulling ways to limit access to Facebook to people over 18 or allow parents more control over their children's profiles. Loading The Communications Minister Stephen Conroy would not comment on Mr Cameron's proposal but has previously said he did not believe the government had powers to pass laws to make ISPs turn off services.

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