Part of the fallout from the London riots has been the clear desire within the police to gain control of social media during 'emergencies'.
Press reports have suggested that the Met, and indeed certain MP's, are in favour of closing websites such as Twitter and Facebook, but they have not (yet) worked out the legal tools for doing so. In a way this is surprising. As far back as 2009 counter terrorism officers were debating the problems posed by social networking sites. Prof David Sloggett, of Kings College London's War Studies Department, told police at a counter terrorism conference in July 2009:
"Many events in the future are going to be very difficult with user-generated content allowing people to put their views online. When the police service is trying to get its arms around the problem and find out the facts, the public may be putting details online which could be in direct contradiction with what you are saying."
Police Review, 17 July 2009.
And all the indications are that the police response to this question will be - close Twitter.