1 million dollars, the vase, which the museum claimed to have acquired through Lebanon, had been looted from an Etruscan tomb in Italy. Evidence was provided by the Italian police to the museum's director Philippe de Montebello, who agreed to return the object. Renfrew criticised the Met for not proceeding with a change of its policies, referring to it as "a museum in denial". He praised the University Museum of Pennsylvania in Philadelphia and the British Museum, both of which have adopted an ethical code, the former as early as 1970 and the latter some ten years ago.

"If a museum accepts the need to create a formal acquisition code," Renfrew said, "if a museum accepts that it is inappropriate to buy illicit antiquities, unprovenanced antiquities, then I'm willing to say that we can let bygones be bygones. Maybe they have to return some recently acquired objects, but we can make progress. However, if a museum was caught red-handed, had to give some of the loot back but does not change its policies, then there's no progress."

He outlined the problem's international proportions by referring to different countries that have fallen victim to heavy looting - from Mali, "whose prehistory and archaeology have been to a significant percent destroyed" to China, where a free market still operates.

The destruction of archaeological heritage, Renfrew said, happens because of looters who dig archaeological sites and sell their contents to private collectors or museums. "Ultimately, it's not the objects that really matter," he pointed out, "it's the information that is lost. A successful excavation can tell us a huge amount about our shared past, whereas the objects, when taken out of context, don't tell us much." As an example of "a happy case of a successful excavation... one that was well published and well restored... one of the triumphs of Greek archaeology" he cited the discovery in 1977 by late professor Manolis Andronikos of the undisturbed tomb attributed to King Philip II, the father of Alexander the Great.

The tomb yielded rich finds, including a golden casket which contained the partially cremated remains of the dead prince, a remarkable metal body armour with gold decoration and a ceremonial ivory-embellished shield. The excavation "tells us an enormous amount about the princely burials in the royal family of Macedonia", Renfrew said. He prompted the audience, which included many friends of the British School and the British Council, to imagine what would have happened had the tomb been discovered first by looters.

In support of his point, Renfrew read a hypothetical entry in an auction house catalogue. "It can be the purpose of such an auction to hide the source," said Renfrew and this is done by following the familiar pattern of covering the tracks or being vague about the country of origin. A striking example of the intentional concealment of an artefact's origin is the Lydian treasure. Parts of it went on display at the Metropolitan Museum in 1984 as the "East Greek Treasure". The Turkish government took legal action in 1987. The Metropolitan Museum gave up and the artefacts were returned, Renfrew said, "because paperwork showed that when they bought this treasure they knew that it was looted from Lydia." And though the so-called Aidonia treasure was eventually returned to Greece from New York, significant contextual information was lost with the looting of the treasure.

With the UNESCO convention of 1970 being "the key dividing line", Renfrew pointed out that the acquisition of antiquities by many museums before this date would be considered inappropriate by today's ethics. "At the same time it would be ridiculous to empty all the great museums of the world of all the items they acquired before 1970," he argued. For museums that have adopted an acquisition code, antiquities obtained before 1970 "can be regarded as water under the bridge unless they are of colossal importance like the Parthenon Marbles or the Pergamon Altar". And though restitution was not the subject of Renfrew's talk, he said that "when the issue of restitution is seriously addressed, one of the most significant criteria would be national importance and association with the building. The case of the Elgin marbles would be one of the strongest and one at the top of the list."

Renfrew moved on to highlight the inappropriate association between major collectors and museums which agree to put up exhibitions that often contain objects of unknown provenance, a "ludicrous" practice which ultimately results in the expansion of looting. "Museums hope and believe that they will receive benefactions of antiquities for which the collectors very often receive very large tax benefits," he said. "The first bit of legislation that I would like to see in the United States would be that there should no longer be any tax benefits for antiquities without documented provenance."

With regard to Greece, Italy, Turkey, Egypt and Mexico - all countries with a rich archaeological heritage - Renfrew suggested the granting of longterm loans "to good or deserving museums". He stressed the necessity of an international agreement that all respectable museums should adopt an acquisition code, a requirement for any loan transaction. "Consideration should be given to declining to lend any material originating from Greece to a museum which hasn't signed such a code" and, by extension, to an exhibition containing looted antiquities. The looting of the past, Renfrew emphasised, should be an issue of greater concern than the display of the Euphronios vase in Rome or New York. "We can only prevent the looting of the past," he pointed out, "if we ensure that the world's international museums live up to what should be their reputation."