GREECE must rank among the most romantic countries in Europe - its classical monuments, its islands, its sunshine and laid-back way of life. At this time of year, people flock there in their thousands to soak it all up.

Yet Greece is also one of the trickiest countries in Europe, a source of tension with its Balkan neighbours and with the European Union (EU), to which it has belonged since 1981. Greece and Turkey eye each other with suspicion across the Aegean Sea. The "Macedonian question" dogs its relations with its northern neighbours. Greece's weak economy and turbulent politics make it a perpetual source of anxiety for the rest of the EU, who suspect that one day they will have to club together to bail it out, or invite it to leave.

I got a strong sense of all of this during a recent visit. It was a joy to be there, but, oh, what a prickly atmosphere. For me, as a Brit, the sharpest thorn was the eternal saga of the Elgin Marbles, which has hit the headlines again.

The saga goes back 200 years, when Lord Elgin, British ambassador to the Turks who then occupied Greece, obtained permission to remove dozens of marble friezes from the ruined Parthenon in the heart of Athens. These were shipped back to England and put on display in the British Museum, where they reside to this day.

After the Greeks threw out the Turks in the mid-19th century, they asked for the marbles back but Britain refused, claiming that they had been legitimately acquired. The Greeks persisted, and the British developed a string of reasons why they should stay: they were safer in London, they formed part of a unique collection of antiquities, and anyway, the Greeks had nowhere to display them.

The Greeks have just skewered that last argument by building a top-class museum right next door to the Acropolis where the Parthenon stands. I visited the museum shortly after it opened last month, and it is truly superb. The whole of the top floor, encased in glass with magnificent views of the Acropolis, is given over to a reconstruction of the friezes and pediments from which Elgin took his marbles. The missing pieces are marked by crude plaster reproductions, illustrating very starkly just how much the British took away with them. It certainly made me feel guilty.

The Greeks are now stirring up the whole controversy, hoping to capitalise on their initiative. Having been brainwashed by the Acropolis Museum's excellent Greek guides, I returned to London, keen to hear the other side of the argument. Last week, I spent an evening at the British Museum admiring the Elgin marbles, which are well displayed in a purpose-built gallery from the 1930s, though lacking the drama of its Athens counterpart. Very quickly you realise that Elgin chose well - the British collection has all the best bits: cavalcades of horses, exquisite figures in flowing togas, great battles with centaurs.

The British Museum is irritatingly coy about the whole furore. While the rest of the world calls them the Elgin Marbles, the museum insists on calling them the Parthenon Sculptures, and the most it will admit to is that there is "a discussion" about where they should belong. But it is firm in its refusal to return them. Its position is that the marbles "are part of everyone's shared heritage and transcend cultural boundaries".

The suspicion is that the museum fears that sending them back would open up a string of claims from other countries whose antiquities it possesses.

And not just the British Museum. Paris, Berlin and many other cities which also have Parthenon marbles are probably secretly lending support, pressing the British not to yield.

I confess to feeling deeply divided on the issue. The key question has little to do with whether the marbles were legitimately acquired or are better off in London - that is mere bickering. The nub is whether the marbles do more to enrich our culture as part of the museum's unique record of human artistic achievement, or back in their place of origin where they can help restore one of the world's architectural masterpieces to completeness. Both arguments have a lot of force.

This is not something on which a decision has to be taken soon, if ever. So any point of view is academic. But having traced the whole argument first hand, I find the Greek position growing in strength and the British position increasingly weak.

Even so, I would be sad to see the marbles leave London.

- Lascelles is senior fellow of the Centre for the Study of Financial Innovation in London, and a former banking editor of the Financial Times.