Channel 4 has won a US libel case against a woman who sought $800,000 (£550,000) in damages after her name was used in a comedy routine by Sacha Baron Cohen.

In a landmark decision that Channel 4 said would benefit comedy writers, performers and broadcasters in the US, a California judge threw out the claim by the woman, who sued under the name "Jane Doe", saying it was obvious Baron Cohen's Ali G skit was not serious.

The woman launched the costly legal action after claiming her name was used in an interview by Baron Cohen's comedy creation with the historian Gore Vidal for the US version of Da Ali G Show, which was screened on cable network HBO and in the UK on Channel 4.

In the interview, Ali G asked Vidal why there was any point in amending the US Constitution as the spoof character had a girlfriend - who shared a name with the plaintiff - who was constantly "amending herself" but to no avail. The woman was also described as a "bitch" and a "minger".

HBO, which first broadcast the programme in 2004, had twice settled out of court over the item.

But Channel 4, which has the international licence for the series as well as handling all foreign sales, took the case to court after the plaintiff pursued charges relating to the show's wider distribution.

Los Angeles superior court judge Terry Friedman threw out the lawsuit, ruling: "No reasonable person could consider the statements made by Ali G on the programme to be factual.

"To the contrary, it is obvious that the Ali G character is absurd, and all his statements are gibberish and intended as comedy. The actor, Sacha Baron Cohen, never strays from the Ali G character, who is dressed in a ridiculous outfit and speaks in the exaggerated manner of a rap artist.

"Ali G's statements are similarly absurd. Altogether, the programme is obviously a spoof of a serious interview programme. No reasonable person could think otherwise."

Channel 4 said the decision was only the second of its kind in the US, after a New York court ruling in favour of NBC comedy show Saturday Night Live.

The action was fought by SDD Global Solutions, the Indian arm of Channel 4's US counsel SmithDehn LLP. Channel 4 described it as a groundbreaking case where "outsourcing" was a "creative solution to running a robust defence".

Channel 4's controller of legal and compliance, Prash Naik, said it was an "important ruling" for Channel 4 and sent out a "clear signal that we will not hesitate to fight unmeritorious claims of this nature".

He added: "US court actions are extremely costly to run and even where a defendant wins, little if any of their costs are recoverable from the plaintiff. As so often happens in cases like this, the 'chilling effect' of the threat of substantial damages and significant legal costs forces defendants to settle with plaintiffs who have no justifiable claim.

"However, combining the skills and expertise of US attorneys with US law-trained Indian attorneys has proved to be an innovative and cost-effective way for Channel 4 to fight and win the suit."

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