DAVID Monaghan is a young man with a lot of bottle. A lot of vodka bottles and a lot of Malibu bottles, to be precise, as these are what he uses in his incredible routines. At 23, Monaghan is the four times Scottish flair bartending champion. For those who don't know what flair bartending is, it's what Tom Cruise does in Cocktail – mixing drinks in an extremely flamboyant manner, flipping and spinning the bottles, glasses and shaker.

Now, you could argue that this is pointless, that drink should be served with minimal faffing about. But that argument would cut no ice with Monaghan, a South African living in Glasgow, the best city in Scotland for flair. Asked why he does this, he gives the answer straight: "It's fun, it looks cool, and chicks dig it."

To this end, he practises for six to 12 hours each day, usually arriving at his space, in an old warehouse by the Clyde, after tea and leaving around midnight. Sometimes, when he returns to his flat, his hands are so numb he can't hold his toothbrush. On the night before I visit, he was up until 4am, running routines with his friend and mentor, Nicolas Saint-Jean, who is regarded as being the greatest ever flairer. He's Federer to Monaghan's Andy Murray.

"He's the person I look up to most," says Monaghan. "I hadn't seen him in a while and I was thinking, 'Oh, he's quite old now. He's in his thirties. He's probably lost his touch.' But he's actually still amazing."

Youth is an advantage in flairing, apparently. Your reactions are fast, you're fit and supple, and you still have the necessary motivation to compete and succeed. But as it involves alcohol, people tend not to get into flairing until they are 18, so there are only a few brief years in which to do well. Monaghan himself only started flairing when he got a job serving drinks in a pub.

Flairing is very competitive. Today, Monaghan will be in London, competing in the Roadhouse UK Final. He will be up against the best in Britain and thinks he could be placed third. This would mean prize money of £350 (the winner will take home £1,500), but there are tens of thousands to be made when you reach the international level. In Las Vegas, the world capital of flairing, bartenders can make $2,000 a night in tips alone. "People live in mansions and drive Ferraris just from doing this," says Monaghan. "I'd like a piece of that."

At the moment, he makes a living by taking students and by performing at events such as promotional launches for bars and new brands of spirits, and private parties for rich people. Although he talks freely about his desire for wealth, I don't think it's money that drives him. He's simply in love, perhaps even obsessed, with the skills of flair bartending.

A measure of this is his disdain for the American style of flair he would have to adopt to make it in Vegas. "It's basically juggling," he says. "A really cheesy circus style. Americans want to see lots of bottles in the air and they don't care that much about what the actual moves are. In an American competition, whoever does the most bottles wins." The record is seven.

Monaghan favours the European style, as taught to him by Saint-Jean, in which flairers find creative ways to move the bottles without juggling. Originality is prized in the world of flair. There's an unspoken agreement among the top guys that they won't copy each others' moves. "I think one thing that makes me unique," he says, "is that I'm really fast."

He isn't kidding. Monaghan demonstrates the five minute routine with which he hopes to impress the Roadhouse judges. To loud dance music (you get extra points for catching on the beat) he throws up to four bottles and a shaker around so quickly that it's hard to work out what's going on. At times it appears objects are orbiting his body under their own steam. One moment he's propelling a bottle into the air by hitting it with the shaker so hard it seems certain to shatter. The next moment he catches the bottle on the back of his palm. Seconds later, he's pouring vodka by turning an actual cartwheel. It's no surprise that, at the end, he's panting.

Monaghan likes to think of flair as an extreme sport – "It would be really cool to be in the Olympics" – and once I've seen his demonstration it's hard to argue. But not every flairer is as physical. Some routines are more like close-up magic, and Monaghan has some unkind words for the fitness levels of the current world champ, an Argentinian called Rodrigo Delpech.

Taking inspiration from gymnastics and from the breakdancers who rehearse their act nearby in the warehouse, Monaghan works out with gym equipment and a punchbag. He's got quite a set-up here. A bar built from bricks, a full-length mirror so he can see how his routine looks, a futon for when he needs to take a break. The only thing he lacks are certain empty bottles.

Friends who work in bars keep empties for him. "But it's quite hard to get Malibu and actually the one that's really troubling me at the moment is Bacardi. Right now I have none. I've got some full bottles that Bacardi gave me a while ago, and I offer those to bars if they give me empties." Monaghan has been flairing for four years. The seeds of his enthusiasm were sown at the age of 10 when he saw Cocktail. Then, while working in a bar in Glasgow, he picked up a couple of tricks from colleagues. Pretty soon he was teaching himself new techniques and had become addicted to flairing. Even now, he can't make a cup of tea without flipping the spoon.

His enthusiasm for Cocktail has waned – "The moves are so easy. You can learn everything Tom Cruise does in one day" – but his ambition has not. Yes, Monaghan has got some bottle, but he's measured too, and has set himself a deadline for success. "I don't really like to limit myself," he grins, "but sometimes I think that if I haven't got a mansion by the time I'm 25 I should change career."