Britain seems to be leading the way in everything, including art. But are today's young British artists collectible? John Windsor finds out. Got your YBA (young British artist) yet? You might not want a shark or a Myra Hindley in your sitting room, or any of Jake and Dinos Chapman's penis-nosed, anus-mouthed kids, among the shock-horrors at the Royal Academy's Sensation exhibition, selected from the Charles Saatchi collection.

Art investors cannot get over Saatchi's role as artists' reputation-maker. He buys cheap, often direct from studios, then prices soar. Can modest investors afford to follow his trail? To discover whether any of his stars have entered the affordable mainstream I visited the annual 20th Century British Art Fair at the Royal College of Art (last days today and tomorrow).

Unlike the London Contemporary Art Fair in Islington, this fair does not aim to be at the cutting-edge of contemporary art. It is more Modern Brit than Young Contemporary - from Sickert to the Sixties, you might say. It shows mainly artists whose reputations have survived the mill of art criticism, but includes three or four contemporary galleries as icing on the cake. So if a Sensation artist's work is on sale at the fair, it means something.

Damien Hirst's agent, Jay Jopling, does not have a stand at the fair. But he made sure to be there on opening day, as did Saatchi, who swept in as the doors opened and set about scouring the stands for fresh talent hidden among the Mary Feddens and Ken Howards.

My first call was to the stand of Eric Franck Fine Art. Not only is Franck displaying Gary Hume and Gavin Turk, both in Sensation, it was he who sold Saatchi Tracey Emin's tent, another Sensation exhibit, which bears the applique names of Everyone I Have Ever Slept With 1963-1995.

Franck, a first-time exhibitor at the fair who has an office but no gallery in London, says: "It's the best piece she has done. At first, I told him, `I don't want to sell it', but it was very important for Tracey to be in the Royal Academy show." He is not disclosing the price.

Gary Hume, a Goldsmiths '88 veteran and a Turner Prize nominee last year, is well represented in Sensation - five huge gloss-paint panels with flat semi-abstract designs such as Begging For It - clasped hands with head- and-shoulders silhouette in the background. For pounds 175 (if you are lucky) at Franck's stand, you can buy one of Hume's edition of 150 screen prints, A Page of Pears, (which look more like sagging balloons). The price, originally pounds 150, is rising pounds 25 for every 10 sold.

Saatchi has plenty of Turks. You are too late to buy his lifesize Pop in the RA - fibreglass pop-star type with pistol in glass case - but you can console yourself with his colourful felt-tip scribbles on paper, Multiple Signatures, pounds 850 from Franck. Or, for pounds 500, buy one of his edition of 137 spoof blue plaques, Borough of Kensington, GAVIN TURK, sculptor, worked here, 1989-1991, the MA artwork which, on solitary display in his studio at the RCA, cost him his degree.

Gillian Wearing is a nominee for this year's Turner prize who made her name with videos of street interviews.

At Mauren Paley's Interim Art stand at the fair, you can buy something of Wearing's that is quite different - a huge, 90cm by 124cm, black and white photograph of Kelly and Melanie (1997), two little girls in a park, one holding the other's mouth in a scowl. Price pounds 6,000.

Paley also has one of Mark Francis's dotty oils on canvas, though not as big as his 244cm by 214cm Negative in Sensation. You could tuck this one, Compression Study (1997), under your arm. Price: pounds 3,500.

Saatchi passed by Paley's stand at last year's fair and bought two names that were new to him: Sarah Jones and Paul Noble. Neither is in Sensation but Sarah Jones' eerie five-foot square colour photograph, The Garden (Mulberry Lodge) (V), in an edition of three, is on Paley's stand at pounds 3,000. Noble's heavily worked pencil drawing of floating lozenge shapes, Sea III, is pounds 5,000.

Another first-timer at the fair is the Hales up-and-coming caff-cum-gallery from Deptford, where Saatchi drops in to buy and where the notorious Jake and Dinos Chapman had their first show. Saatchi has also bought from Hales colourful, blocky abstracts by the older John Moores prizewinner David Leapman.

Leapman's acrylic on canvas, Sharp Eye Check Out - two figural constructs on yellow background - is pounds 4,800 at the fair and there are plenty of drawings at pounds 600-pounds 1,000 by Heath, who featured in Saatchi's YBA show last year.

The nearest you could come to buying a Sensation work in miniature at the fair is to pay pounds 2,500 for Simon Callery's 30cm by 40cm untitled abstract painting at Anthony Wilkinson Fine Art.

Also worth a look at Wilkinson's stand: the new name Johnny Spencer's illustrated story boards on such wittily banal topics as How the Brain Works and History of Kung Fu. Saatchi has bought some. Price: pounds 700.

These days, even galleries more used to dealing in dead than living artists think it prudent to sign up a YBA. At the Spink-Leger stand, Lowell Libson, who has acquired a formidable reputation in the trade for swashbuckling auction bids of pounds 50,000 or so for Victorian watercolours, has devoted the entire space to the energetic abstract impressions of land and sea by the 34-year- old Pembrokeshire artist Daniel Backhouse, who has contracted exclusively to the gallery. Prices: paintings pounds 1,000-pounds 6,000, drawings pounds 800-pounds 1,000.

Backhouse is no Damien Hirst. His thickly applied paint is more reminiscent of Auerbach. Saatchi used to collect Auerbachs but has now sold them. Perhaps Libson knows something that Saatchi does not.

20th Century British Art Fair, RCA, Kensington Gore, London SW7 (today and tomorrow 11am-7pm).