Susan Moore

It seems that hardly a week goes by without the threat of another great work of art leaving these shores. Certainly Tate director Sir Nicholas Serota must think so. Just as he announces, with palpable relief, that a private benefactor has stepped forward and promised £12.5 million to 'save' Sir Joshua Reynolds's celebrated portrait of Omai from export (more of that later), the gallery may well feel obliged to embark on a new campaign to save yet another costly treasure. This jewel is a recently discovered 'lost' portfolio of 19 highly finished and perfectly preserved William Blake watercolours, the original illustrations to Robert Blair's poem 'The Grave', commissioned by the publisher Robert Cromek in 1805.

There is a certain irony in the fact that the art market least affected by the fallout of 11 September was probably Islamic art. After all, the big players in this small, specialist field are unlikely to have incomes dependent on the Western stockmarket – and they are as rich as Croesus anyway. Biggest of all is Sheikh Saud bin Mohamed al-Thani, cousin of the Emir of Qatar, who has spent hundreds of millions in just five years – hoovering up everything from Islamic metalwork to Mamluk glass, manuscripts, Isnik pottery, and Indian and Arab jewellery, much but not all destined for a projected national museum and library.

The art and antiques business is as unpredictable as an English summer. And it is not only the works of art that confound market rules and crystal balls. The fairs that serve as the dealers' collective showcase similarly defy expectations. Who would have thought, for instance, that fair entrepreneur David Lester could put up a tent on a forlorn intersection in West Palm Beach - not only on the wrong side of the tracks but just feet away from them - and find himself with one of the most glamorous and successful art fairs in America? Or that a charmless convention centre on the ring-road around Maastricht - a town no one had heard of until the eponymous treaty - could become the venue for quite simply the best art and antiques fair in the world?

If a French national museum wishes to buy a work of art at auction, it simply exercises its 'right of pre-emption'. Substituting itself for the final bidder, which is what this means, is less fair than it sounds - word invariably gets out about the museum's intentions and few bother to bid. In France, as in Italy, Germany and Spain, any work of art deemed of national importance cannot legally leave its shores, a circumstance which once again significantly reduces its market value. Good news for the cultural patrimony, perhaps, but rather less cheery for the owner. Britain's approach, in contrast, is the most liberal in Europe - its system of controlling the export of national treasures while acknowledging the property rights of the individual is peerless.

C.