A court order has forced Twitter to hand over the personal details of a British user, raising further questions about free speech on the internet and the possibility that celebrities and corporations could head to US courts to unmask users who break injunctions or make libellous comments.
Four individuals – three councillors and an official at South Tyneside Council – subpoenaed Twitter in a Californian court, where the company is based, in a bid to reveal who was behind an anonymous whistle-blowing blog called Mr Monkey.
The action, believed to be the first case brought by British claimants, is itself contentious because the council involved has paid for the legal proceedings for the individuals and has already cost taxpayers more than £70,000.
The implications for Twitter, which will have to spend time and money researching the orders while it faces a continuous barrage of privacy questions, are significant. The users in question could now face legal action as well as being identified.
The Sunday Telegraph reported that the Superior Court of California had granted the order, which forces the company to release contact details, location information and computer addresses of the individuals behind four accounts believed to be linked to the Mr Monkey blog.
Ahmed Khan, an independent councillor, has admitted to being the owner of one of the accounts but said he was not the author of Mr Monkey.
Mr Khan, who in April was told that a request had been lodged relating to his account, said: "I don't fully understand it but it all relates to my Twitter account and it not only breaches my human rights, but it potentially breaches the human rights of anyone who has ever sent me a message on Twitter. This is Orwellian. It is like something out of 1984."
Media lawyer Mark Stephens, who represented WikiLeaks' founder Julian Assange when the US government tried to obtain his Twitter details, said those running websites criticising corporations or even regimes could be affected.
He said: "There is a possibility those running anti-government or company websites will be targeted. These law actions can be taken by anyone, corporations, totalitarian regimes for example. We need to seriously think what this could mean for people trying to expose wrongdoings."
One person who could benefit from the ruling is Manchester United footballer Ryan Giggs, who could potentially use a similar order to force the release of details of some 75,000 Twitter users who named him as the holder of a super-injunction.
John Hemming MP used parliamentary privilege to name Giggs publicly, but the player – who was attempting to conceal an alleged affair with former Big Brother contestant Imogen Thomas – has pursued Twitter through the UK courts to obtain the individuals' details.
The deadline for the UK court order passed on Friday, apparently without Twitter responding, and it has no legal status in the US. "Giggs could have done this weeks ago," Mr Stephens said. "In commercial litigation, where the principles are established, you quite often begin proceedings in another country to aid proceedings in the main jurisdiction you are fighting it."
One reason Giggs might not have gone to the US initially was because the subpoena would have revealed his identity. Mr Stephens added: "Privacy tourism has begun, there is no doubt about that."
South Tyneside Council has been criticised for pursuing the legal case, but a spokesman said it "had a duty of care to protect its employees", adding that the current legal costs amounted to "less than £75,000".
He said: "We can confirm we have received information from Twitter. This is currently being investigated by technical experts."