When stones and marbles are fought over

It is the world's biggest game of marbles. For centuries, nations have plundered each others' most beloved artefacts, including the Stone of Destiny, only to claim "finders keepers" when asked to return them.

The list of lost goods covers the spectrum of history, from a manuscript containing the oldest sentences written in Welsh, to an Aztec feathered head-dress, jewels once thought to belong to Helen of Troy, and a collection of Norse chess pieces.

The stone of Scone, seized from Scotland in the 13th Century was taken from Westminster on Christmas Day 1950 and smuggled north. Ports were watched, King George was kept informed, and the BBC banned jokes about it. It turned up in April, 1951 at Arbroath Abbey, and was taken back to London.

In 1984 pressure for the stone to be returned to Scotland reached a head when a Commons motion was tabled demanding its return. It took another 12 years for the Government to hand it back

Among the greatest hoarders of all is the British Museum. The most disputed artefacts to be plonked in Bloomsbury are the Elgin Marbles, which once adorned the Parthenon in Athens. Lord Elgin bought them from a Turkish overlord in 1801, and sold them to the museum in 1816 for pounds 35,000.

Glenys Kinnock, the Labour MEP, has joined calls for the marbles to be returned, and in return hopes to see Welsh artefacts returned from England. The Gospel of St Teilo, a religious manuscript, has been in English hands for 1,000 years.

For the most part, the artefacts are priceless. The world's most valuable chess set, dug up on the Isle of Lewis in 1801, recently became the subject of a custody battle between the islanders and the British Museum. Both kings are insured for pounds 1m each.

But it is not just the British who are expert at laying their hands on other people's cultures. The Greeks are anxious to reclaim the Venus de Milo from the French, who have given the statue pride of place at the Louvre for 170 years, while Moscow is brimming with just as many foreign treasures.

As well as some of the world's finest impressionist paintings, seized as trophy art from the Germans at the end of the Second World War, the Russians have Priam's Treasure. The hoard of 100 Turkish objects and jewels, found by Heinrich Schliemann in 1873, was taken from Berlin by Soviet soldiers in 1945.

One of the most unusual disputed artefacts is the Quetzalcopilli, a feather headdress of the Aztec emperor Montezuma, which has been in Vienna for 100 years. The Austrians say the plumage "would rot in the tropics" and claim it never belonged to him anyway.