Boris Johnson has taken on George Clooney in the row over the Elgin Marbles by comparing him to Hitler.
The Hollywood star was asked about the sculptures, taken to Britain from the Parthenon in the 19th century, during a London press conference to promote his new film.
He replied: "Even in England the polling is in favour of returning the marbles from the Pantheon [sic], the Pantheon marbles."
He said parts of the Parthenon had been given back by the Vatican, suggesting that returning the parts held at the British Museum was "probably the right thing to do".
The Greek government wants the marbles to be returned there.
Clooney later added: "It was one of a hundred questions at a press conference, a Greek reporter asking me about the marbles – and I just said I thought it was probably a good idea if they found a way back at some point."
Clooney was backed by his co-star Bill Murray, who said: ""There's plenty of room in Greece. England could take the lead on this."
Johnson weighed in from the other side, telling the Telegraph: “Someone urgently needs to restore George Clooney’s marbles.
"Here he is plugging a film about looted Nazi art without realising that Goring himself had plans to plunder the British Museum.
“And where were the Nazis going to send the Elgin marbles? To Athens! This Clooney is advocating nothing less than the Hitlerian agenda for London’s cultural treasures. He should stuff the Hollywood script and stick to history.”