The more crudely painted and flaky the trade signs, the better the Americans like them. Two bashed-up early 20th-century signs, one for an apothecary showing a rhinoceros, the other for a baker, made $1,150
America is short of history; Britain has too much. Which is why Americans pay fancy prices at New York auctions of Americana and folk art while in Britain such auctions do not exist.

Until Wednesday (10.30am), that is, when Christie's South Kensington is holding the country's first folk art sale. Although everything in the sale is British, it was collected by a pair of eccentric Americans, the late John Judkyn and Dr Dallas Pratt.

Their British folk art is reckoned by Christie's to be the first major collection of it ever formed. "In Britain", says James Ayres, director of the John Judkyn memorial, "folk art has been the poor relation of its academic cousins and seldom mentioned in polite circles".

Funny, because plenty of books have been published on it, with titles such as British Folk Art, People's Art, Popular Art, even Family Art. And as long ago as 1762, William Hogarth organised an exhibition of signboard art in London. But without a big collection to offer, the art - if art it is - would never have been brought together in a dedicated auction.

In America, the quest for heritage has swung up-market. The folksy and naive are no longer the main offerings at Christie's New York sales. Last month, the top two lots in its "Important American Furniture, Folk Art and Decorative Arts" sale were carved mahogany Federal furniture:$101,500 (pounds 64,650) for a set of 10 Federal shield back chairs.

But in the same sale, the pulling power of folksy curios remained obvious: a pair of cast iron andirons in the form of baseball players fetched $7,475 (about pounds 5,000) and a 19th century gilded tailor's sign $8,050 (pounds 5,300). The more crudely-painted and flaky the signs, the better the Americans like them. Two bashed-up early 20th-century signs, one for an apothecary showing a rhinoceros, the other for a baker, made $1,150 (pounds 650) . But the curios that Americans would kill for are carved, painted cigar-store Indians: one fetched $7,475 (pounds 5,000).

You can spot the same American taste at work in this week's London sale: the turn-of-the-century sheet tin and wood trade sign in the form of a chimney sweep is estimated pounds 1,500-pounds 2,000, a wrought iron and copper pawnbroker's sign, pounds 800-pounds 1,200. So hurrah for a lot that could never be other than British - a fretwork model of a steamroller, without estimate, which means that under pounds 100 is expected.

Miniatures and silhouettes are all the rage in the salerooms at the moment, encouraged by the Dynasties exhibition at the Tate, and by the successful disposal of the Frederick Joachim collection of portrait miniatures and silhouettes at Christie's South Kensington this week, raising pounds 83,964. On Thursday (12 noon), it is Bonhams' turn with the Christie collection of silhouettes.Most estimates are in the hundreds.

Not to be missed: the usual glorious rag-bag of cheaply-estimated autograph letters and manuscripts at Phillips, Thursday (11am). A warrant signed by the Prince Regent in 1817 ordering the embezzler John Croaker to repay pounds 12,000 is est pounds 60-pounds 80. And there is the usual lock of Charles II's hair, est pounds 200-pounds 300.

For auctions nationwide see pages 14 and 15.

John Windsor