Prosecutors in Los Angeles have said they will demand the extradition from Switzerland of French movie director Roman Polanski, whose arrest on under-age sex charges 30 years ago has caused an international incident.Swiss police took him into custody on an international warrant when he arrived in Zurich on Saturday for a film festival. A host of famous film makers have called for him to be liberated, and one suggested that festivals should be inviolate: “They have always been a place where borders don’t matter. If you get rid of this extraterritorial nature, you limit the free movement of artistic work.” A longtime resident of France, Polanski fled sentencing in the United States over sex and sodomy with a 13-year-old girl in 1977. While the 76-year-old awaited the next move in a Zurich prison, a senior Swiss minister spoke out while on a visit to Paris. She said: “We had no other possibility under the cooperation agreement with the US than to implement an arrest warrant when a wanted person set foot on Swiss soil.” Polanski gave a young aspiring actress champagne and a drug before the acts he has long admitted took place. Some of the world’s best-known intellectuals and film stars have described his detention as “unimaginable and disproportionate”.