Workmen were putting the finishing touches yesterday to Ancient Greece’s newest and most extravagant showcase, the New Acropolis Museum, due for a fanfare-filled inauguration today. But conspicuously absent are the very relics which the €130m futurist building was expressly designed for: the Elgin Marbles.

The airy top floor of the 25,000 square metre museum, offering an unparallelled view of the Parthenon atop the Acropolis a couple of hundred yards away, has been reserved for when the Marbles — as many Greeks devoutly hope — return.

Yet as dozens of dignitaries arrived for the opening that Antonis Samaras, the Greek Minister for Culture, promised would be “a magical atmosphere with musical surprises” (and drain some €3m out of the Greek taxpayer’s pocket), it seemed likely that the Parthenon Hall, as the glass-domed top floor is called, would remain empty for a considerable time to come.

Last week Mr Samaras contemptuously dismissed an offer by the British Museum, which claims ownership of the Elgin Marbles, to lend them to Greece for three months. According to British diplomats, Gordon Brown politely turned down an invitation to attend the opening. No British government figure, in fact, will be there.

There are exhibits enough on the other floors to impress even the most jaded museum-goer. They include the best of archaic, classical and Hellenistic art gathered under a single roof for the first time. Since October 2007 more than 140 tonnes of sculptures have been painstakingly ferried from the top of the Acropolis into the museum by a sequence of cranes. This operation, in which the boxes containing the statues are suspended more than 100 feet above the street for hours at a time, is expected to cost €2.5million.

The glass-and-concrete museum, which from the Acropolis parapet looks like a gargantuan shoe box with its lid askew, was designed by Bernard Tschumi, a Swiss architect, to be tough enought to withstand earthquakes — not a bad idea in what is the shakiest country in Europe, geologically speaking. It has been a quarter of a century in the planning.

The original idea behind it was to answer the British Museum’s claim that Greece had nowhere to adequately house the Elgin Marbles. “The British said we don’t deserve the Parthenon sculptures because we’ve nowhere to put them,” Mr Samaras said in a recent interview. “Now, though, we have one of the best museums in the world.”

The vacant Parthenon Hall, some hope, could itself be a silent argument for the Marbles’ return. “The strangeness of the missing parts becomes all the more visible,” said Dimitris Pantermalis, an archaeologist appointed as the museum’s director.

To drive the point home, the sides of Athens’s buses, trolley buses and metro carriages have been emblazoned with likenesses of the Panathenaic procession frieze that makes up most of the British Museum’s collection, gathered together (the Greeks would say stolen) by Thomas Bruce, the Seventh Earl of Elgin.

To draw in the public, the museum’s admission price for the rest of this year will be just €1, rising to €5 in 2010. The goal is for a maximum 2.5 million visitors a year which, given Greece’s present tourism downturn, appears over-optimistic. A walk through the hallways — ample and well-lit but with all the charm of an airport terminal — takes about three hours.