The rules of the game of marbles have hardly changed in half a century. The Greek prime minister or foreign minister or culture minister visits Britain and in his or her wake there are a slew of stories about how the issue of the return of the Elgin Marbles has been raised and may be moving towards a (from the Greek point of view) satisfactory conclusion. And then the British Museum, where they are displayed, says it is open to dialogue but is not looking to lose major parts of its collection, thank you very much.

Exactly this was happening in the days after the visit of prime minister Kyriakos Mitsotakis last week. One of the people he met was the museum’s chairman, George Osborne (it was a second meeting between the two), and on Saturday a BBC story appeared online headlined “Deal to return Elgin Marbles to Greece at advanced stage — reports”. These reports consisted of a “Greek insider” speaking to a Greek newspaper and saying that an agreement was “90 per cent” complete. The British Museum issued a statement reiterating its desire to create “new positive long-term partnerships around the world” but that the trustees were “not going to dismantle our great collection as it tells a unique story of our common humanity”.

And yet for two reasons the background to these repeated demands and polite rebuffs is changing. The first is because of a growing belief in polite society that the London marbles should be “reunited” in Athens with those in the Acropolis Museum. And I’ll come on to the second later.

In the meantime it’s Tuesday of the week that Mitsotakis is here and we’re recording an interview for a Stories of our times podcast with Mary Beard, probably Britain’s most famous classicist, whose book on the Parthenon and its sculptures appeared in 2002. Beard is a trustee of the

museum, but not famous for toeing party lines. If you want to understand the history of the marbles and the complexity of the arguments about their ownership, Beard is a fine place to start.

They were being destroyed — then Elgin comes along . .

How good are they? When she was on Desert Island Discs and was asked what luxury should accompany her she asked for some of the Parthenon Marbles. “They are extraordinary works of art,” she says. “With the friezes people constantly are amazed at the way that sculptures which are only a few centimetres thick can show horses lining up and men sitting on them. They look so deep, you could get six or seven hooves in a row, and it’s all within a few centimetres.

Brilliant. It is utterly brilliant!”

The main friezes now in the British Museum were on the inside of the temple, high up. The pediment sculptures were originally at either end, though much was destroyed by a huge explosion in 1687 when a Venetian mortar shell ignited gunpowder stored inside the Parthenon by its Ottoman garrison.

Even before the Turks took Athens in 1458 much of the sculpture on the Parthenon had been damaged by antipagan Christians. For centuries the marble was mined for new buildings by Turks and Greeks alike. By the time in 1801 that the British consul to the Sublime Porte, Lord Elgin, requested and received permission from the Ottoman authorities to remove sculptures not attached to the building, the Acropolis was, Beard says, “a real mess. The part-destroyed Parthenon is in the middle. And there’s this kind of military barrackscum-village all around it.”

The reason this matters is that the argument about where the marbles should be displayed has been coloured by assertions that Elgin was some kind of looter. When the new Acropolis Museum was opened in 2009, Antonis Samaras, then the Greek culture minister, accused Elgin of having ”vandalised” the Parthenon, of “having just taken the front of a whole piece of art and put it in a foreign museum”.

And it’s true that — following the brutal practice of the time — slabs of sculpted marble would have the undecorated backs sawn off to make shipping easier. So I ask Mary Beard, what would have happened to the British Museum marbles if they had been left where they were? “Was there a significant chance that a large part of the Parthenon would have been damaged or lost? I think the answer to that is yes. That has no impact on what you think Elgin’s motives were. But yes, they were being destroyed, the building was being destroyed. And Elgin comes along.”

Elgin originally displayed the marbles in his garden. But then he “went bust”, Beard says, and offered to sell them to the British government.

The purchase went ahead and in 1816 they moved to the British Museum.

It’s not an uncommon trope of those supporting their return to suggest that Greeks need the marbles back more than the museum needs to keep them.

So I ask Beard how significant they are for the British Museum. “Hugely significant. But I think that they mean different things wherever they are, right? They mean something different in Athens, something different in London. In the British Museum you see these marbles next to Persian art and that reveals something about both Persian and Greek art. Also there is a way in which the Parthenon sculptures have over the last 200 years become embedded and formative in European art outside Greece.”

But does that mean that the Elgin Marbles should stay in London? Beard says that she is agnostic about the marbles. “I see good and bad arguments on both sides of this question. The more I’ve worked on it, the more I’ve sat on the fence. I think that it represents one of the big problems of cultural heritage, which is who owns things? Where do they belong? Who has a right to see them?And a lot of my friends are on completely different sides of this issue. And we don’t stop being friends.”

In 2019 about 1.8 million visitors went to the Acropolis Museum, paying €10 each in the summer and €5 in the winter. However, 6.2 million people visited the British Museum in the same year for free, although not all will have seen the marbles. Despite this it’s easy to see that there is greater popular demand in Greece for the marbles to be returned than there is in Britain to keep them.

And there is that second factor. Next year the museum — saddled with an ageing and damp building — will announce a huge and expensive programme of rejuvenation. My suspicion is that the trustees will look to loan the marbles back to Greece while that process is under way.

But would the Greeks give them back? Remember that 90 per cent figure? Well, right there is your missing 10 per cent.