As an accountant with a showman's instincts, he first transformed snooker, then fishing. Now he's on the case for Leyton Orient
Dagenham's answer to P T Barnum, a man with his finger in more pies than Mr Kipling, Barry Hearn has probably done as much to change the face of British sport as anyone else alive. And now he has a confession to make. "I never go anywhere without money," says Hearn, 47, looking as near as he gets to shame-faced. "My wife always tells me it's terribly working class, but I'm always carrying it. Not a lot - maybe five or six hundred, a thousand." He pats his suit expansively, "I don't need it, but it's almost like it's symbolic."

When Barry Hearn qualified as a chartered accountant in the mid-1960s, he continued with the car-washing round he'd had as a kid: "It was making pounds 10 a week, and I couldn't see the value in giving that to someone else." Three decades later, he is sitting in the chairman's office at Leyton Orient Football Club, which belongs to him. The previous owner, Hearn observes with the colourful turn of phrase for which he is widely celebrated, "was treating it like a girlfriend: he only saw it once a week, and it was costing him money."

The club's finances have turned around somewhat since Hearn's arrival, but Orient's endearingly ramshackle Brisbane Road ground is longer on charm than profit-potential. The place looks like the set of an Ealing comedy; hemmed in by houses, skyline awash with chimney pots. It's all old-fashioned hustle and bustle at the main entrance, too - players leaving for Fulham ("No, seriously Tony, get us a Snickers") and local pensioners coming out of the boardroom, where they've just been playing bingo. Finding Barry Hearn amidst this communitarian idyll is like noticing a half-submerged alligator in a crowded savannah watering hole.

Hearn is powerfully built, sharply-suited and wears the sort of tie only a man of real influence could get away with. ("This is one of my quiet ones," he smiles, "It's a shame the photo has to be in black and white.") Is he offended if people say that Orient seems like the opposite of everything he stands for? "No, because it's a lovely reverse touch." He looks affectionately at the bizarre bark-effect wall covering. "With all the changes that we're making, I'm gonna keep this like it is: it's just so tatty. It's a statement in itself."

Statements are Hearn's business. "Give me a soap box," he proclaims, "and I can be dangerous."

In the Eighties heyday of televised green baize action, Barry Hearn's Romford-based Matchroom empire did not just rule the roost, it was the roost. One year - 1988 - Hearn managed all four world championship semi- finalists. And those were the days when the dramas played out at Sheffield's Crucible Theatre for the fortnight of the Embassy World Snooker Championships would hold the whole nation in thrall.

"It was Dallas with balls," Hearn remembers proudly. "It was almost scripted ... you had your good guys and your villains: Alex Higgins was the bad boy, Dennis Taylor told jokes, Tony Knowles was the good looking stud, Steve Davis was every grandmother's favourite son and Tony Meo cried." These days it's the manoeuverings of different brightly coloured balls that keep Britain glued to the TV on Saturday nights. "The problem the game has got now," Hearn explains, "is that all the young players are Steve Davis clones, and they can all play, so they're eliminating all the characters."

In the early Seventies, when Hearn first got involved in snooker - acquiring a chain of London halls for the investment company of which he was finance director - the sport had a different kind of image problem. "Snooker halls were bad places to go in those days," Hearn remembers. "There was one in Lewisham that had a shotgun under the table. Your mum would give you a clip round the ear if she found out you'd been there. Ten years later, grandmothers were giving their nephews membership cards for Christmas presents."

How much of Hearn's snooker sanitisation campaign was real and how much was show, remains in some doubt ("Who's going to go to snooker halls in the day," Barry wonders, "except villains and layabouts?") Either way, it led to an undeniable triumph of Thatcherite entrepreneurship, as Hearn and Matchroom exported the sport - players, tables, cues and all - to the Far East. "When they first phoned up from Bangkok and said would we come over, we thought `Blimey, where's Bangkok? Of course we'll come'." They asked how much so we said `Hmmm, [plucking a figure from the air] $20,000?' `Yes.' `Shit! Should have asked for more'." Hearn overcame the rare trauma of underestimating how much someone was prepared to pay him by demanding first class travel, limos, penthouse suites and police escorts.

Matchroom's invasion of the Pacific Rim seems to have been run along the same lines as the first rock'n'roll package tours. "To be almost approachable, that was our key: visual, but not touchable. If they bought 20 tables, they'd get Steve Davis, but we wouldn't say how long for." The Matchroom blitzkreig would sweep through eight clubs in a day. "Rockefeller once said, `Always leave the other man with a bit of bread in his mouth'." Hearn observes approvingly. "Don't skin them ... Nearly skin them: tease them enough to make sure you're invited back. Even if they're the biggest dogs in the world, they don't need to know that you know it."

Before Barry Hearn, British sport's idea of commercial opportunism was Dennis Compton using Brylcreem or Henry Cooper splashing Brut all over. Shrewdly applying his pre-snooker experience of overseas textiles licensing deals, Hearn built the whole gleaming exploitationary edifice the modern sportsperson calls home, more or less from scratch. The Matchroom star, Hearn pointed out to various interested parties, didn't just play snooker, he put on after-shave, carried bags and wore slippers as well. What maker of quality timepieces could resist Barry's call: "I've got these snooker players who are on TV all the time, why aren't we wearing your watches?"

It was the commodification not only of the game but also of the people who made it, that was Hearn's real masterstroke. If he feels any guilt about his indirect responsibility for They Think It's All Over, he is keeping it to himself

"When Steve Davis was on Spitting Image as Steve `Interesting' Davis, eveyone thought it was terrible," Barry remembers, "but I said `No, it's great'. Out of that came the Interesting book, the Minolta campaign for boringly reliable photocopiers, it went on and on. It was like reverse psychology: instead of Muhammed Ali going `I'm so beautiful', here's this bloke who says `My best chat up-line is to ask a girl if she wants to come up and see my 147 break on video.' It's all branding: people would roll their eyes but they loved it."

Whatever happened to the Corinthian ideal: two brave innocents fighting it out for the fun and the honour of it? "I've never believed sport was like that," Hearn insists. "I've always thought that sport was a soap opera. The characters are in some ways more important than the sport itself - I don't say that to detract from the value of it, but there's no question of ability being the only criterion. Otherwise how would you've got Frank Bruno fighting Mike Tyson in a blaze of publicity? It wasn't that Frank Bruno was the best heavyweight in the world, but he was a marketable heavyweight and it was a marketable occasion. All sport is an occasion, and it's how you create that occasion that counts."

In 1994, Barry Hearn dropped a supermarket shopping trolley into the still waters of the angling community by launching Fishomania ("Fishing like you've never seen it!" - just signed to a new three-year contract with Sky TV). The plan was for Hearn's much loved super-middleweight boxing champion Chris Eubank to do a bungee jump to get the day off to a flying start. Sadly, things went awry. "Chris Eubank didn't do the bungee jump in the end," Barry explains, "I think he was worried about his retinas, so Chris Quentin from Coronation Street did it instead."

It is this indomitable spirit that makes Hearn and Matchroom so difficult to disapprove of. And besides, any organisation whose corporate phone manner involves frequent recourse to the phrase "Be Lucky" has to have something going for it. "I love this little ground," Barry says sentimentally, looking out across the Orient terraces. "If I don't appreciate what I've got, I don't deserve to be here."