A prodigiously talented violinist, Julian Rachlin's career was boosted by his youthful appeal. But once puberty kicked in, he had to fight to stay in the limelight, Anna Tims heard.

Back in 1983, a Greek pianist, Dimitris Sgouros, was outlining for a queue of international journalists his ambition to become one of the world's great musicians. He already seemed well on course: his concerts were sell-outs, the media was vying for his favours and he was still only 13 years old. And then something happened that obliterated his success: he grew up.

It's the sort of story that must haunt the Lithuanian violinist Julian Rachlin, who makes his London recital debut at the Barbican on Sunday. At 23, Rachlin is about to celebrate 10 years on the international circuit. He was discovered when he won the Eurovision Young Musician of the Year competition at 13, after which the conductor Lorin Maazel snapped him up for a European tour with the Pittsburgh Symphony Orchestra. Two years later he became the youngest soloist ever to perform with the Vienna Philharmonic and was signed up by Sony for three compact discs.

Then the inevitable happened. The round-faced boy became a man with stubble on his chin; the virtuoso skills - miraculous coming from a child - seemed suddenly no different from performances by any other celebrated soloists. As a result, his contract with Sony was terminated and the media transferred their attentions to the new wunderkinder emerging from the Far East.

"It took me some time to manage the step from what they always call a prodigy," he admits. "The crucial years were between 17 and 19, when I had to come of age and show audiences there was more to me than the pure little boy causing sensations with virtuoso pieces. The transition was very difficult, though, because I was suddenly expected to go out there and play like a fully developed artist."

His playing has developed from an athletic sensuality which prompted Gramophone magazine to declare him "among the finest players of the day". He is about to sign a recording contract with EMI and his diary is fully booked for the next three years. And as a defiant gesture to emphasise his coming of age, he has recently grown a beard.

Rachlin is one of the lucky ones, but he feels bitter about the system which plucks children from obscurity, hypes them, pressurises them then drops them when the "aaaah" factor fades. The film Shine graphically documented the story of the Australian pianist David Helfgott, who was pushed into the spotlight as a young boy then driven to a nervous breakdown by his ambitious father.

However, in an age when image is everything, child prodigies are a marketing person's dream and it takes a strong character to resist the glittering prizes dangled in front of them. Since the days of Mozart, the spectacle of an infant in party dress standing pigeon-toed on the concert platform has enthralled audiences, and a CD featuring a winsome 10-year old is likely to sell twice as much as the same work played by a bespectacled baldie in tails. In New York, the Juillard School of Music churns out formidably talented teenagers such as the 15-year-old pianist Helen Huang, and cellist Han-Na Chang who made her public debut, aged eight, seven years ago. The New York Times critic recently condemned a concert by Helen Huang, declaring a 15-year-old had no place on stage with the New York Philharmonic. Rachlin agrees: "It's pure circus," he says. "These very young performers have impeccable technique but nothing more than that." So does he consider his own juvenile debut with the Vienna Philharmonic a circus act? "I personally think not," he says. "My teacher's philosophy was an entirely different one. He didn't give a damn if I f****d up this or that; for him, interpretation was far more important than technique."

Born in Lithuania to musical parents, Rachlin claims he first wielded a violin at the age of two. "I originally wanted to be a cellist, like my father, but under the Communist regime there was no chance of getting a cello. One day my parents brought home a violin and I thought, heigh ho, why not give it a try." When he was four his parents emigrated to Vienna to escape anti-semitism in Lithuania. "We had $4 per person per day to live on, but luckily my mother got a job at the conservatoire. When I was six I began learning the violin seriously and enrolled with the eminent pedagogue Boris Kuschnir."

It was thanks to the wisdom of Kuschnir and his parents that Rachlin did not become another David Helfgott. Despite the lucrative offers that followed the Eurovision competition, they restricted him to no more than 15 concerts a year and ensured he led as normal a life as possible. "After I won the contest I was bombarded," he recalls. "All the big managers wanted to engage me and drew up contracts for 100 concerts a year. It was a difficult time because I didn't understand what was going on, and I'm grateful to my parents and teacher for preventing me joining this circus."

Now, however, his schedule is a punishing one with over 100 concerts a year and most of his early 20s have been spent on a plane seat. "It can be suffocating but it's become an addiction," he confesses.

None the less, he is depressed by the current state of classical music and by the sort of culture that rates image above talent. Before his contract with Sony was terminated, the record company had asked him to release a crossover record in an attempt to recapture his childhood sales. Rachlin refused.

"The classical recording industry is facing a big crisis at the moment and the big labels are no longer happy to let the artist choose what to record. They insist on coming up with something completely different, which is a big problem for us.I don't want to be considered a Vanessa Mae or a Nigel Kennedy. But times are changing, even for conservative people like me. I can see that crossover music in a climate like this is the only sensible thing to do, so I'm working out my own agenda. It will be something that has never been recorded before."

He also regrets that the recording industry lays so much importance on technique, thereby killing the art of individual self-expression. "This era has produced a very poor selection of musical personalities," he says. "It worries me that performers seemed scared to show what's inside them." Rachlin is not reticent about unleashing his emotions on stage. After a few yearning, almost painfully sweet bars of Prokofiev's first violin concerto during a rehearsal he emerges out of breath, his floppy hair drenched in sweat.

For the present, music must serve as his only emotional outlet - his schedule does not allow for lasting relationships. In the rare interludes between concerts, however, he chain smokes, listens to pop and loves football and lager. "I'm a wild man," he says proudly. "I party after concerts - that's when life starts."

It worries him that the new child prodigies have no life outside the airport and the concert hall. "There are more and more very young players emerging, mainly from Asia where they are willing to work 20 hours a day. They don't have time for friends and you have to wonder how they will cope with sexual relations when they are older."

Despite the pressures and the disruptions Rachlin admits he is at his happiest on the concert platform. "With or without my beard I've always been totally focused on music and I can never resist an engagement. Music is my most powerful language and I shall always have this urge to share my strongest emotions with my audience. And I am glad that they now listen to me for that reason - and not because I'm a sweet little schoolboy who can play Mendelssohn with the grown ups."