The High Court has ordered an injunction to be served through the social networking site Twitter for the first time.

In yesterday’s ruling, the court said issuing the writ over the micro-blogging site was the best way to get to an anonymous tweeter who was impersonating a right-wing commentator.

The Twitter account, blaneysbarney, was impersonating Donal Blaney, a lawyer and Conservative blogger. The account, which was opened last month, features a photograph of Mr Blaney followed by a number of messages purporting to be by him.

The Court said that unknown imposter should stop their activities and that they should reveal themselves to the court. The owner of the fake account will receive the writ next time they enter the site.

Mr Blaney’s clients include prominent Conservatives including the popular and controversial political blogger Paul Staines, known to the blogosphere as Guido Fawkes. Mr Blaney has described the tweets that are falsely in his name as “mildly objectionable” but believes that they are politically motivated.

Matthew Richardson, the barrister who won the injunction, said the ruling was a big step forward in preventing anonymous abuse of the internet.

“People have to learn that they can no longer hide behind the cloak of anonymity the internet provides and break the law with impunity," he said in a statement.

Legal experts said the decision could have far reaching implications those who impersonate others using social-networking sites such as Facebook and Twitter.

Dr Konstantinos Komaitis, a lecturer in IT and Telecommunications at Strathclyde University's law faculty, said: “I think this is a landmark decision to issue a writ via Twitter.

“You are creating a precedent that people will be able to refer to. It only takes one litigant to open the path for others to follow.

"The law tends to be quite cumbersome and slow, so to have a court deliberate on something like Twitter - so hot, so relevant - it shows quite impressive engagement.”

Online impersonations, particularly of celebrities, have become increasingly prevalent following the success of Twitter. Leading users, such as the actor Ashton Kutcher and pop star, Britney Spears have hundreds of Twitter impersonators.

Earlier this year, the Foreign Office was forced to deny reports that the Foreign Secretary David Miliband had used Twitter to leave a tribute to Michael Jackson after his death. His impersonator had tweeted: "Never has one soared so high and yet dived so low. RIP Michael."

Twitter has been forced to react to the problem. Earlier this year, it allowed people to “verify” the authenticity of their site. A seal is attached to the pages of high profile Twitter accounts with singer Lily Allen amongst those taking up the verification scheme.

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