Elgin Marbles question renewed as Athens museum opens

The long-overdue New Acropolis Museum is now scheduled to open in Athens on 20 June. However, the impact will be felt most acutely in Bloomsbury, central London, as one of Britain's longest-running international disputes takes a potentially decisive turn.

Athens' share of the marble sculptures that once adorned the Parthenon temple on Acropolis hill, the crowning achievement of classical Greece, now have a permanent home 300 metres below the original site. The glassy, angular new museum is daring and eye-catching in itself, but it's the contents of the third and top floor – and the way they're arranged - that will make the world sit up and take notice.

The alignment of the building follows the layout of the surrounding streets, at an angle to the Parthenon, but the top floor makes a dramatic shift. As if unconnected with the floors below, the glass enclosure faces in a different direction, with its corners jutting over the edge, precisely aligned with the Parthenon above. The ancient temple fills the gallery's giant picture-window like a Hollywood star on a drive-in movie screen.

Spicing up that architectural flourish is a piece of cultural dynamite. The centrepiece of the top-floor gallery is an exact replica of the 160m-long frieze of delicately sculpted marble that ran along the inner walls of the temple when it was completed in the fifth century BC.

The frieze depicts the annual Panathenaic Procession in honour of the goddess Athena, the high-point of the city's summer festivities. In its original form the frieze consisted of 115 panels, but the ravages of time, warfare, negligence and vandalism have reduced that number to 94. Of the surviving slabs, all but two are in Athens or the British Museum, with the lion's share (56) in London. These, along with 15 metopes (rectangular slabs that were placed over the temple's columns) and a further 17 pedimental figures, are what we know as the Elgin Marbles.

Over the two centuries since workmen employed by the Scottish peer, Lord Elgin, began stripping the Parthenon in the early 1800s, various plaster casts have been made of the missing sections of frieze, enabling the curators of the new museum to reconstruct the complete sculptural narrative, mirroring the precise dimensions of the original. The 36 panels that remained in Athens are safely in their new home – stained brown because they've never been subjected to modern cleaning methods, which strip away some of their skin. Filling the gaps are white plaster copies of the plundered panels, most of which have resided in London since 1816, when Lord Elgin sold his collection to the British government for £36,000.

The absence of the originals on the reconstructed frieze, and the glaring whiteness of the copies put in their place, is a powerful broadside aimed at Britain by a Greek government that is dedicated to bringing the marbles home.

At the museum entrance, a signboard describes the Parthenon Gallery as a "dress rehearsal for a permanent exhibition of the entire frieze". For the Greeks, it's no longer a matter of if the marbles are returned, but when. Bernard Tschumi, the museum's Swiss-born architect, signed off his €130m creation with the words: "I'm convinced the marbles will come back. Their return will make sense straight away."

Professor Dimitrios Pandermalis, the academic who has overseen the six-year project, speaks with the quiet certainty of someone who knows his big moment is at hand, after a very Athenian sequence of delays that have postponed the opening by nearly a year. Building anything in Athens is bound to turn up a treasure or two in the subsoil, and as the holes were being sunk to house the museum's load-bearing piles, a 5,000-year-old urban settlement was discovered, which had to be carefully excavated and incorporated into the design. They've achieved this triumphantly, turning part of the ground floor into a glass walkway directly above the ruins, giving the impression that the museum is suspended in mid-air.

Further delays were caused by the necessary removal of 25 modern dwellings, which kept local planning lawyers in fees for months. The Professor's patience may have been taxed, but he's now on the verge of delivering a diplomatic and cultural thunderbolt of the like Athena once threw.

"We have here the surrealistic picture of a divided monument," he told me as he walked me through the exhibition. "The buildings of the Acropolis laid the foundations of Western civilisation. We should have this monument as complete as possible. It's clearly ridiculous when you have a body in London and a head in Athens to keep the two pieces separate."

The body in question belongs to Iris, a messenger deity who took part in the gathering of the gods at the culmination of the Panathenaic procession. You can find her on Block V of the British Museum's Parthenon Galleries, directly opposite the entrance. Her body is intact, but her wings and head are missing, because the top left corner of the block was broken off, probably by Elgin's men.

"This is almost a culturally criminal case," Professor Pandermalis exclaimed, before adding, diplomatically: "dating back 200 years, of course."

Now that Athens has a museum where priceless antiquities can be safely stored without fear of weathering or pollution, one of the British Museum's strongest arguments for keeping the marbles in London is fatally weakened. And concerns about geological instability seem unfounded: since the building was finished, Athens has been struck by two earthquakes, but its internal "suspension" made light of them.

The British Museum's position is that "The current division of the surviving sculptures between museums in eight countries, with about equal quantities present in Athens and London, allows different and complementary stories to be told about them, focusing respectively on their importance for the history of Athens and Greece, and their significance for world culture". However, its contention that generations of visitors have been able to appreciate the sculptures at eye-level rather than high up on a building is no longer relevant: its Athenian counterpart now does the same. And the Bloomsbury spin that the two collections tell "different and complementary stories", when they actually depict a single event in the ancient Athenian calendar, is plainly absurd.

Some see the opening of the New Acropolis Museum as altering the landscape of the 200-year-old argument over the Elgin Marbles. The Museum's Trustees are unmoved about the present division, saying the arrangement "gives maximum public benefit for the world at large and affirms the universal nature of the Greek legacy". But those who see it for themselves, and consider the yawning gaps in the original frieze, may come away believing there's no longer an argument at all.

The New Acropolis Museum, Athens (00 30 210 924 1043; newacropolismuseum.gr), adjacent to Acropolis station on the city's Metro, opens on 20 June.

The British Museum, Great Russell Street, London (020-7323 8000; britishmuseum.org) opens 10am-5.30pm (to 8.30pmThursdays and Fridays), admission free.