Sir Paul McCartney has written a letter to Russian president Vladimir Putin to personally request his help to free 30 people who have been held in the country since September (13). Altogether, 28 activists for environmental organisation Greenpeace and two journalists were arrested and charged on suspicion of piracy and hooliganism following a protest against oil drilling in the Arctic ocean. Reports on Monday (11Nov13) suggested the group, which was originally held in the city of Murmansk, has been transported to pre-trial detention centres in St Petersburg. Russian authorities have not given a reason for the move, which has sparked concern for their safety. It has now emerged that The Beatles legend has stepped in to help the detainees by asking Putin to intervene. In an open letter to the president, posted on his official website, McCartney writes, "Vladimir, millions of people in dozens of countries would be hugely grateful if you were to intervene to bring about an end to this affair. I understand of course that the Russian courts and the Russian Presidency are separate. Nevertheless I wonder if you may be able to use whatever influence you have to reunite the detainees with their families?" This is not the first time the singer has stepped up against Russian authorities. He has been a keen supporter of the jailed Pussy Riot band, whose members, Nadezhda Tolokonnikova and Maria Alekhina are currently serving time for staging a protest against Putin in Moscow last year (12).