London - Former Beatle Paul McCartney said on Thursday he has written to Russian President Vladimir Putin urging him to intervene to help 30 people jailed after a Greenpeace protest in the Arctic."It would be great if this misunderstanding could be resolved and the protesters can be home with their families in time for Christmas. We live in hope," the ageing British rocker said in his letter sent last month and now published on his website.McCartney, who is currently in Japan, said Putin had not yet replied, but the Russian ambassador to Britain had responded by saying the situation of the detainees "is not properly represented in the world media".The so-called "Arctic 30" were detained when the the Russian Coast Guard boarded their Dutch-flagged Greenpeace vessel after several activists scaled a state-owned oil platform on 18 September in a protest.Russia has since put the 30 people in prisons in Saint Petersburg after moving them from the Arctic Circle city of Murmansk.McCartney, whose hits with the Beatles included "Back in the USSR", denied that the protesters were anti-Russian or doing the bidding of western governments."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?" he wrote.