While western sanctions bite more deeply into the Russian economy, and there’s talk of a new Cold War, the British Museum has stunned the world with an extraordinary gesture. It’s lent a priceless Greek antiquity to the State Hermitage Museum in St. Petersbur to mark that institution’s 250th anniversary. It’s a statue of the river god Ilissos — part of a group called the Elgin Marbles, brought from the Parthenon in Athens to London by Lord Elgin 200 years ago. Ownership is disputed by Greece.

But why lend to the Russians? And will they send them back? Have the Brits lost their marbles?

“The Museum’s always been very clear that they’re delighted to lend any of their artifacts to any museum that gives them an assurance that they’ll give it back again,” says historian and lawyer Dominic Selwood. “Last year, they lent more than 5,000 objects to museums around the world.”

The British Museum says it is confident it will get the statue back. The two museums have a long history of friendship and co-operation. Making the loan, say the Brits, is an important, human gesture in difficult, turbulent times. It might even help thaw the new Ice Age setting in between the two governments.

Good luck with that one, says James Nixey of the Chatham House think tank in London. “A little bit of cultural diplomacy in the form of an Elgin Marbles loan isn’t going to cut it with the Russians or the Brits after the annexation of Crimea and the downing of Malaysian Airlines Flight MH17 over Ukraine. That is way beyond this kind of cultural diplomacy, I’m afraid.”

The loan is having the opposite effect of diplomacy in Athens. In fact, it’s sparked Olympian fury there. Among those hurling verbal thunderbolts, economist Elena Panaritis.

“I feel provoked and outraged,” she says, claiming that Lord Elgin stole the marbles and common decency requires that the British Museum should restore the artifacts to their rightful owner. The loan to Russia, says Elena, is yet another slap in the face for Greece. “We’re going through a terrible economic crisis, we’re trying to get out of it. And it seems we continue the humiliation of the modern Greeks with actions of this sort.”

The British Museum insists that Elgin saved the marbles for posterity; they are now a part of world culture and many more people will be able to see them and enjoy them in London than in Athens.

Ilissos is expected to back on his plinth at the British Museum by the middle of next month.