Audley Harrison is a very good heavyweight boxer. He was Olympic champion. He is unbeaten as a professional. He has become the anointed heir to the heavyweight throne. He fights next week but is most unlikely to lose. He is British into the bargain. At almost 18st and 6ft 5in he would dwarf most contenders and champions from previous decades - and remember that professional boxing as we know it is essentially a 20th century invention. Harrison is as big as Primo Carnera, "The Ambling Alp", who was regarded as a complete freak in the 1930s, when he became heavyweight champ through fixed fights before ending up as a novelty wrestler on the vaudeville circuit.

Audley Harrison is a very good heavyweight boxer. He was Olympic champion. He is unbeaten as a professional. He has become the anointed heir to the heavyweight throne. He fights next week but is most unlikely to lose. He is British into the bargain. At almost 18st and 6ft 5in he would dwarf most contenders and champions from previous decades - and remember that professional boxing as we know it is essentially a 20th century invention. Harrison is as big as Primo Carnera, "The Ambling Alp", who was regarded as a complete freak in the 1930s, when he became heavyweight champ through fixed fights before ending up as a novelty wrestler on the vaudeville circuit.

Unlike Carnera, Harrison is nimble and talented. He cannot be accused of being "manufactured" because he manages and promotes his own affairs. He gets his sparring done in the ruthless gyms of Las Vegas. He is good-looking after a fashion and changes his hairstyle with Beckhamesque frequency. He can talk the talk - he has it within him to do not only the Ali schtick but also the schtick that would have been Ali's had he been born in south London. He has a foothold on American TV. The BBC have already invested over a million in him here.

It has not all been plain sailing, however. He is 32 - almost the same age as the "superannuated" Ali was when he beat George Foreman in the 1974 "Rumble In The Jungle" - but is frequently accused of acting as if he were 10 years younger. And he has sometimes appeared not to be in impeccable shape. He has fought no one of note, has been unapologetic about it, and this has prompted the BBC to move his fights from prime time to late-night slots.

I first met Harrison following his Olympic triumph, in a bookshop in London's Docklands where he was plugging his (no doubt first) autobiography, and it did seem he had the prize-fighter's ego on him - Audley did not want to enter the shop until his books had been more prominently displayed. But what was he doing there, this serious proponent of the hardest art? Selling a few books for sure but there was more to it than simple economics. This was partly about image-building. Here was a prize-fighter operating in cultural mode.

During the Ali years you would be lucky if you found a single boxing book beyond Gilbert Odd's Encyclopaedia of Boxing. Then there was Hemingway, and Mailer's The Fight (which described the "Rumble in the Jungle"), Hunter S Thompson's musings about the same Zaire experience, AJ Liebling's earlier The Sweet Science (a collection of his New Yorker columns) and George Plimpton's Shadow Box, a book of participatory journalism in which he got beaten up by Archie Moore. But those were classed as "literature".

The tendency of these books is to cast boxers as strange and beautiful creatures, the violence of their world swirling and mythical. They also embrace the idea that the boxers themselves are aware of their mythical roles. But if this is to be the boxer's cultural identity, is it correct? There seems to me to be a great dichotomy between the way "culture" views boxers and the way boxers view "culture" - if indeed they view it at all.

There are films too. Rocky I was all right and quite touching, though the rest in the series were execrable. The Champ, with John Voight, was terrible. Going back to the Fifties there was Bogart's last screen role, as the hard-bitten boxing writer in The Harder They Fall, based on the novel by Bud Schulberg, which was in turn based on the career of Carnera, who sued but had run utterly out of cash. It was the last defiant act of a noble victim. Someone once asked me to explain the career of Frank Bruno. By coincidence, I happened to have a copy of The Harder They Fall on me. I just handed him the tape. It was not an attempt to illustrate Bruno's career but nevertheless the film remains a narrative template for so many others.

I watched Scorsese's Raging Bull three nights on the trot when it first came out. I thought it was the greatest work of art of all time, but I was only 16. Now I am not so sure. In fact I think it is rather corny, and the casting of the Sugar Ray Robinson character - Robinson being the most dashing and elegant boxer of them all, with a fleet of Flamingo-pink Cadillacs, several personal groomers and the best left hook in the business - was outrageous. The actor looked and moved like a duck.

There have been a few other films worth watching - Someone Up There Likes Me with Paul Newman as Rocky Graziano being one - and there was a cameo appearance by La Motta in the original version of The Hustler, but that was about pool. The best one is Fat City starring Stacey Keach and a young Jeff Bridges, directed by John Huston in one of his last films. It is the story of an alcoholic ex-contender - Keach as Billy Tully - trying to get his life back together for one last hurrah in the ring: the classic materials of the boxing myth, executed without sentimentality, perhaps because Huston had once been an experienced amateur boxer himself and knew what he was talking about. It was based on a book by Leonard Gardner - not bad but not as good as the film because you can somehow tell it is written by an academic.

Likewise the best short story about boxing, "Rocket Man", was written by a former boxer, Thom Jones, for his collection The Pugilist At Rest. A young light-heavyweight, Billy Prestone, is recalling a desperate night in the corner with his trainer WL Moore, another alcoholic. Prestone tells Moore: "You said, 'Kid, there's a third wind. It's between here and death. Don't be afraid. Go on ahead and grab a hold. The third wind. It's all yours'."

The authenticity of Fat City and "Rocket Man" make them different experiences to culture's more vaunted boxing works. I found Mailer's The Fight ridiculous. Like Hemingway's Parisian sparring sessions it seemed to me an activity designed to impress other men who were not used to such activities. Anyone who has boxed (as I did, poorly) will know that there is a chasm between the writerly perception of violence and the almost workaday acceptance of it when you are inside the ropes. In the ring, adrenaline stops you from feeling the pain at the time, even when you are down (unless you get kidney-punched). It is only the next day that you feel it. Meanwhile, going about one's training, one is concerned less with the majesty of the noble art than with the excruciating fragility of one's knuckles.

The only time Hemingway sparred with anyone who knew how to box - a minor Canadian writer named Morley Callaghan - he was decked and humiliated. He responded by accusing the timekeeper, F Scott Fitzgerald, of letting the round run overtime on purpose just to see him get a beating.

I would not expect Audley Harrison, whom I spoke to by phone in Las Vegas last week, to be au fait with all these writers and films. He was not. He has enough on his plate, being concerned with the central business. Nor did he probably notice, when patting his autobiography on that Docklands shelf, that it is a shelf that has burgeoned since Gilbert Odd's day. As boxing itself has declined to the status of a minor sport, indeed imploded into a political and economic chaos presided over by rival governing bodies, so its iconography has inexorably risen.

The brouhaha surrounding the "Rumble In The Jungle" - when even the bucket-carriers became sages and Mailer, Thompson et al got whole books out of it - may have got on some people's nerves at the time. But if so the experience has been infinitely worse the second time around. We have had the film When We Were Kings and a Hollywood Ali hagiography that doubled as a Will Smith vehicle, plus myriad elegiac tomes and memoirs (including my own). The actor Mickey Rourke took the retro boxing obsession to extremes by becoming a professional one himself, though he never risked himself against anyone but extreme patsies. Surely the Hemingway syndrome again.

Audley Harrison does have his own frame of references, however, and they are confined to boxing itself and the business of boxing. They are not cultural. "I have my own strategy," he told me, "but I've taken bits of all of them - Ali, Joe Louis, Chris Eubank, even going back to Jack Johnson. I'm acutely aware of my own worth. People like Johnson sold themselves short because they were told there was no other option. There is always another option."

Similarly, when Harrison talks about Ali, it is in terms of his boxing attributes not his iconic ones. "He mastered his talents," Harrison said. "He had great movement and good speed of punch, but he wasn't just a dancer. He took a lot of punishment. He did whatever it took to win."

It is interesting that Harrison cites Johnson, the first black world heavyweight champion under Queensberry Rules, a supreme tactician who was prosecuted under the Mann Act for consorting with white women, had to flee the US and lost his title in a suspicious fight against Jess Willard. Many have waxed lyrical about his tragic fall. (Miles Davis, another artist compelled by the ring, made an album of scarifying jazz-rock as the soundtrack music to a documentary biopic.) Like Carnera, Johnson ended up in vaudeville. A fatal car smash probably saved him from where he was headed. The same might be said for Mike Tyson today, though one hopes not. Perhaps this is boxing's unconscious cultural appeal: it always tells the same story, and people like the same stories - the classic boxing narrative invariably involves thrills and spills, moral struggle, violence, defeat, triumph, pain, humiliation and the pathos of a guaranteed car crash at the end.

There is an argument that cultural affirmation helps those it is bestowed upon. You could argue that Ali is the exception. But I can't see it. I have met Rocky Graziano in New York, and pugilistic dementia had reduced him to infantilism. Jake LaMotta once recited to me the opening lines of Raging Bull again and again. "I am played by superstar Robert De Niro," he kept adding. It is not culture but veteran boxers' associations that now look after these damaged men.

One danger inherent in the actual implosion of boxing - as opposed to its cultural elevation - is that it could well run out of icons for future use. Today's most famous boxer, Oscar "The Golden Boy" De La Hoya, may be a multi-millionaire, but is virtually unknown outside boxing and Las Vegas. When boxing's titles were still intact, one of the pleasures of following it was seeing who came through the system. Britain's leading boxers of the Eighties - Barry McGuigan, Lloyd Honeyghan and the Welsh puncher Colin Jones - all came through and all retained steadfast control of their own original identities as men as they did so. These men did not fall victim to the compulsion to self-mythologise, to pander to culture. Now, amid the entropy of boxing's decline, it is mandatory to be loud - to be Ali - to get noticed. Lennox Lewis could be the last quiet-man champ. Our last crossover boxing star, Prince Naseem Hamed, was a pulverising hitter, but he borrowed almost his entire schtick from Ali. His boxing style was borrowed from his former stablemate in Sheffield Herol "Bomber" Graham, a balletic stylist and the only boxer I have met (perhaps apart from Tyson, a vulnerable, abused soul who eventually took refuge in nihilism) to have an overview of what he was doing and had anything of interest to say about subjects other than boxing.

Graham was totally uninterested in boxing as a sport. He preferred horse-riding and photography. He just happened to be exceptionally good at boxing. I met him in a somewhat basic Bloomsbury hotel the morning after he had put a young prospect, Rod Douglas, in hospital with perhaps the most brilliant display of boxing I have seen. Graham was distraught. He didn't know whether to go to the hospital and visit Douglas or not. "You see," he told me. "I had always thought of boxing as art."

Thom Jones, the author of "Rocket Man", offers the following view of why the intelligentsia wants boxing to be like art: "Maybe they are brainy enough to realise fear and cold enough emotionally to revel in it. Remember that the Roman upper class were the most avid fans of gladiator spectacles. I think Mailer and Thompson are highly opinionated and often wrong, though they speak with such authority they can buffalo a reader into thinking they know what they're talking about. Most writers I have talked boxing with have always talked of it in inflated terms. It's not magic or anything. I just liked the gym and the characters in it and it was a way to avoid going home at night.

"There has never been much of an articulate pro fighter except for Tex Cobb," Jones concluded. "And he now drinks 50 cups of coffee a day." (If so, that would be an improvement. Randall "Tex" Cobb, a former heavyweight "white hope" of the Eighties, was a famous drinking and womanising hell-raiser who was also the subject of a Sports Illustrated investigation into fixed fights. He was beaten so badly in a title bid against Larry Holmes that the TV commentator Howard Cosell announced his resignation on air. Asked if he would like a re-match with the fleet-footed Holmes, Cobb replied: "Yeah, in a phone booth.")

And the truth is that the Ali situation is not as rosy as it is painted, and never has been. When he became champion he allowed himself to be used by the black separatist Nation Of Islam movement, which allied itself with the Ku Klux Klan as an act of pragmatism while believing that "white devils" had been transported to Earth by spaceship. Admittedly, he has renounced all of that and is now a devout Sunni Muslim. However, he earned far less from boxing than is popularly assumed and has to stay on the road the whole time to pay the bills and the IRS. His one true friend is Howard Bingham, a photographer, who has been there since the beginning. TV stations around the globe made capital out of his appearance at the opening ceremony of the 1996 Atlanta Olympics, where he was filmed on a podium shaking so badly he could barely hold on to the Olympic flame he was toting so emblematically. Millions were said to have been "moved" by the spectacle but personally I found it troubling and voyeuristic, and feel sure that Bingham would have done so too.

Ali did not begin life with much and nor did Harrison. He was abandoned by his mother at an early age. Whatever he has gained he has scuffled for. He is streetwise and if "culture" can advance him in any way he will make use of it, just as "culture" will now use him. A clever element of the film Fat City is the use of the haunting Kris Kristofferson song "Help Me Make It Through The Night". That seems to me the boxer's experience in essence. It may be all of ours too, but nowhere except boxing is it so compressed and starkly lit.

I put it to Harrison that though he had made his own luck, he had still been lucky and he candidly agreed. "That's why it's a tough experience," he said. "There are so many good boxers who aren't going to get anywhere. It could be a fake dream but you're still going to be taking the punishment. You're waiting for a light that might not be there. Usually it's an optical illusion."

In Thom Jones's "Rocket Man", before the light-heavyweight Billy Prestone carts his trainer WL Moore off to re-hab, Moore gives an impassioned soliloquy about Prestone's up-coming title shot: "It's going to be sweet, kid. It's going to be magic. And when you take him out, don't bounce around like you're surprised you won. Play it cool, deadpan. Dead black eyes. It will scare the next person you fight. It will drench him in fear. He will think: 'This fucker isn't human'. Like Norton before Foreman. Like Spinks before Tyson."

Prestone was on his feet. He put his hands up and pumped out a jab. "And then I move up and go for the big guy."

"Yes, you're making the transition from local hero into the big time and it's a sucker's game and the big ones eat the little ones up there, but you'll make out, and after you win, hang on to that title with your life." Moore reflected a moment and spoke bitterly. "There's nothing more useless to the world than a washed-up prize-fighter."

What a dream. What a vehicle for poetry. And what a different reality.

Audley Harrison's next fight is on 8 May in Bristol