Bernard Jacobsen, the one-time Daily Mail journalist turned Cork Street art dealer, believes himself to be the polar opposite of his friend Charles Saatchi, Britain's biggest, most dedicated and most secretive collector of contemporary art. "We decided to go on a diet together when middle- age spread got us," says Jacobsen. "When the time came to start eating again, Charles had lost three stone; I'd put on a pound. That's about the size of it; you just can't stop Charles when he's got a bee in his bonnet, or a go-kart under his bum."
Saatchi races go-karts for the fun of it, but he likes to win. He is said to have spent pounds 50,000 on his karting hobby last year, which is what he paid for Damien Hirst's The Physical Impossibility of Death in the Mind of Someone Living, which most of us know as a 14ft tiger shark in a tank filled with formaldehyde. In choosing to back the fishy, feisty and often funny art of Damien Hirst, Saatchi has picked a clear winner. In a remarkably short time, Hirst has become one of the most famous (or infamous) living artists, darling of the tabloids and nice little earner. Since catching Saatchi's thousands with his pickled shark, Hirst has moved from a council flat in Deptford to a chic pad in Chelsea, where his greatest fan and patron lives.
Not that Saatchi is keen to hang out with artists; he's not in the habit of inviting them round for drinks in his cool, white Modern house designed by cool, Modern London architects Munkenbeck & Marshall. Home is where his art is - or at least it houses a tiny part of his 1,000 or so artworks, divided between Chelsea, the whiter-than-white Saatchi Collection in St John's Wood (beautifully designed by the late Max Gordon) and the secure warehouses of Momart, the art storage experts. Saatchi likes to buy art (the latest, the punchiest, the whizziest), entire shows of the stuff at times, but he doesn't like to get too involved with those who produce it.
"He is overwhelmed by the urge to buy," says Brian Sewell, art critic of the Evening Standard, giggling. "His focus is so diffuse that he appears to have no eye at all. I certainly don't think he buys what he does for profit; most of what he buys is ridiculous. Collectors on the scale of Saatchi buy for other reasons; very few of them are sane. Look at Queen Christina of Sweden: mad as a hatter and a lesbian to boot. She bought vast paintings and then had them cut to size to fit her chambers."
Charles Saatchi's motivation remains unclear. What we do know is that he did not get where he is today by playing Mr Nice Guy. At the end of a lecture Maurice Saatchi (Charles's exuberant brother and business partner) gave to the Design and Art Directors' Association (D&AD) in London last year, he "revealed the untold secret behind the name Saatchi". It was an acronym, he told his cooing audience; it stands for "Simple And Arresting Truths Create High Impact". He added: "It's our name, our nature."
("Actually," says Brian Sewell, "It's an Arabic name for clockmaker.")
Charles Saatchi made his fortune from advertising. The impact the north London brothers created with advertising campaigns for the Health Education Council (the pregnant man ad), the Tory party ("Labour Isn't Working"), British Airways and Silk Cut was very similar to that created by Damien Hirst (pickled sheep), Marc Quinn (bust made from the artist's frozen blood) and the sticky young American artists currently on show at the Saatchi Collection.
"It's sound-bite art," says Bernard Jacobsen, "very close to images used in contemporary advertising. But then, the relationship between fine art and advertising has become entangled over the past 30 years and Charles has been very much a part of that process."
Sound-bite art, perhaps, yet this is the stuff that museums of the future will want to show: Saatchi's incomparable collection of young, contemporary British and American art will be in big demand over the next few years.
There are many Saatchi observers (sympathisers, artists and rivals), who believe that at some point in the near future, Charles will hand over a sizeable part of his collection to the new Tate Gallery of Modern Art at Bankside. A dedicated Saatchi Wing in this mighty pounds 106m temple of modern art might even bring Charles the social outsider firmly into the ranks of Britain's smart avant-garde establishment. It would give him a knighthood if he wanted one ("he doesn't," says Jacobsen).
Saatchi is a big player on the art world stage, but keeps himself to himself. He does not attend his own openings, preferring to play silent and intense poker and Scrabble games at home for money with Gerald Ratner, the jeweller, and Michael Green, head of Carlton Communications. Recently, however, he has been chivvied out of his Chelsea lair by Nicholas Serota, director of the Tate Gallery who, with yawning gaps to fill in the gallery's poorly funded collection of contemporary art, needs Saatchi.
Serota encouraged Saatchi to give a rare televised speech at last year's Turner Prize award ceremony. Saatchi's horse, Damien Hirst, was, after all, first past the post. What Saatchi said was revealing.
Some of the art (the art he collects), he said, appears to be "tasteless, cynical and uncouth, but I think it's because sometimes we all are". The Tate might not see itself as a home for "tasteless" and "cynical" work, but they want what Saatchi has more than almost anything else.
There may be one small gap to be bridged before they stand a firm chance of getting it. This gap is an episode dating back to 1982 when Charles's approach was brought into question and he resigned from the gallery's clubby inner-ring, the Patrons of New Art. Why? Because he was accused of trying to manipulate the contemporary art market to his advantage by lending the Tate nine works by the New York artist Julian Schnabel. Get the paintings in your private collection on to the public walls of the Tate and, so the logic goes, their value will shoot up. Put them into the auction rooms as soon as possible afterwards and you may well make a killing.
A while later, Saatchi did unload his Schnabels. But he has done this with other artists. In fact, the reason Charles Saatchi upsets the essentially parochial world of Cork Street dealers is that he likes to corner the work of a particular artist, hoard it and then, for whatever reason, sell it in bulk; the effect of this can slash that artist's value overnight and rip the pockets out of dealers trying to clean up in Saatchi's wake. In the hot-house world of modern art, Charles Saatchi is like a one-man Stock Exchange; no one dealing on his floor has much of a chance.
From the late Eighties when he had built up a collection of 800 or so artworks worth around pounds 100m, he began to sell in earnest. Out went his Sean Scullys, Sandro Chias and Julian Schnabels. By 1991, he had sold about 100 works worth around pounds 18m. (Perhaps he was clearing out the American Minimalists that his former wife, Doris Lockhardt, had encouraged him to buy. The two are not on easy speaking terms. Charles has since re-married.)
This has led to accusations that Saatchi is no longer a collector, but a dealer. He is said to have made more money from dealing in artworks than advertising. And, because he is so secretive (some say he is shy, others that he enjoys the kudos of being cool and reclusive, and refusing to give interviews, even though, according to Jacobsen, he reads all the papers avidly), his rivals can never know his game.
The truth, or at least the closest it is possible to get to the truth, is not so neat.Saatchi is clearly a man who loves a keen deal (he bought 10 out of 13 artworks shown by Anthony Wilkinson, an unknown young British artist fresh out of college for a bargain pounds 4,000 at this year's Art Fair). Yet his keen deals seem to be done without great thought of future profit. A true enthusiast, he goes to as many shows of new art as he can. He has his checkers, but he never buys unless he really likes a work. Even so, it is the deal itself which clearly excites Saatchi most. Anyone who has bought, say, an E-Type Jaguar at a bargain price will understand the feeling.
"The way he buys and sells is far too haphazard," says Sarah Kent, art critic of Time Out and author of the official Saatchi Collection catalogue, "for a man who is far from haphazard." Kent is not in Saatchi's pay. "I have only met him three times," she adds. "Charles Saatchi buys artworks like Imelda Marcos bought shoes; it's an obsession and without it the public might never have caught on to the work of, say, Rachel Whiteread [who cast the celebrated House in Hackney three years ago], Jenny Saville [Saatchi bought the entire contents of her first major show and helped set her up in a studio in the US] or, of course, Damien Hirst [Saatchi paid pounds 25,000 for the boy wonder's Away From the Flock; he keeps the notorious and once ink-stained sheep in his 60ft art gallery reception hall at home]. He's intoxicated by art."
Brian Sewell, for whom Saatchi and all his artists are a monumental joke, agrees. "His dealing is utterly incoherent. I imagine he sells things because he is bored of them. He can't be strapped for cash."
Saatchi appears to collect art in much the same obsessive way as others do classic cars or children do stamps and comic books ("He has a tremendous collection of comic books," says Alfred Munkenbeck, architect of his Chelsea home). There is no guarantee that prices of these things will rise.
"In any case," says Colin Gledell, auction room correspondent of Art Monthly, "you can't predict how much a Damien Hirst is going to be worth in a few years' time. If Hirst chooses to go into film directing, which he may well do, the price of sheep and sharks might fall. I think what Saatchi likes is the shock value of these works.
"Yes, there has been a lot of discussion recently of whether he is a dealer first and a collector second, but I think he both loves art and loves to haggle."
("He sure does," says Alfred Munkenbeck. "When we began work on his house back in 1988, Charles was as a happy as a clam. We did a house with a cool, minimal look. Charles's new wife, Kay, wanted a lot of detail and gradually the work extended and the cost rose from pounds 600,000 to pounds 1.1m. When it came to settling our bill, Charles wanted to give us half of what we reckoned was our due. It all led, very unhappily, to court. I had the feeling that, right or wrong, Charles just wanted to win so badly.")
Saatchi's artists choose to keep mum if, like Damien Hirst and Jenny Saville, they have done well by the man; others are simply grateful to have a patron at all. "When Saatchi came and bought most of my work last month, I thought it was great," says Simon Wilkinson. "I hadn't seen what I was doing as commercial and was pleased to get the pounds 4,000; it's pounds 4,000 I wouldn't otherwise have, and it's paid off my overdraft. I had met him once before; that was at the Anderson O'Day Gallery when he bought all of Simon Callery's show for pounds 20,000."
The critics, whatever they say, love the mysterious, apparently irrational Saatchi art circus. They trot off eagerly to Saatchi-less openings, drink Charles's champagne and tittle-tattle behind his back. Yet, he is the only big-time collector of the very art that museums from Los Angeles to Tokyo are beginning to want in increasing bulk as they increase in number.
Charles Saatchi is bound to be the target of mistrust and jealousy. Perhaps he does behave like a high-handed kid. Perhaps he does want immortal youth (Damien Hirst might be able to help). Perhaps he does want fame and glory. All that we can be sure of is that Charles Saatchi's impulsive collecting appears to be incurable. Only this week he was trying to snap up the greater part of Paula Rego's new paintings (a strange homage to Walt Disney characters), even before anyone had a chance to see them at the Hayward Gallery's forthcoming "Spellbound" show. Charles Saatchi simply has to be one step ahead of the game.