The classical music world can be a cruel place. Cruel to kids who practise five hours a day through their tender years, slog through music college, achieve a reasonable mastery of their instrument — and then discover that, if they are very lucky, they might just earn a pittance at the back of the second violins in some shabby opera pit.

But cruel, too, to those who make success look too simple. Supreme talent, displayed with seemingly “effortless” ease, can carry you to the top very quickly in the concert world. And if you can do it all with a dazzling smile and a modest demeanour — rather than the tortured grimace and prickly vanity of so many mixed-up prodigies — you might well become the most sought-after young virtuoso on the planet.

But then the sniping starts. Instead of being admired, your dazzling technique is cited as evidence of superficiality. “Yes, very suave, very slick,” your critics allow. “But where’s the sense of struggle? Where’s the substance?”

That reaction has been the story of Maxim Vengerov’s life. Or a recurring leitmotiv of it, anyway. “I was blessed with great musical energies when I was born,” he once told me. “My task is to control and transmit them.” That’s not boastfulness talking. It’s frank self-knowledge. Connoisseurs will argue for ever about who is the “most gifted living violinist” — if such an epithet has meaning. But few will argue with the proposition that Vengerov has been the most discussed phenomenon in the fiddle world for most of the past two decades. To watch him on the platform and hear the sound he produces is like observing a spectacular waterfall or glowing sunset. He seems like a marvel of nature, untouched by human agency. His tone is an unbroken silver thread. His pianissimo could melt stone, and his technical flourishes dazzle diamonds. Sleek and dapper in his trademark 19th-century frock coat, he’s constantly on the balls of his feet, hips swaying, like a sprinter warming up. His body and his fiddle (a glorious Strad called the Kreutzer) seem to form an indissoluble unity.

Of course, the phenomenon is not anything like as natural as it seems. Vengerov was born in the freezing Siberian city of Novosibirsk, the only offspring of the oboist in the local Philharmonic and the director of a children’s orphanage. Brought up in a tiny basement apartment, he had a miniature fiddle thrust into his hands at the age of 4, displayed astounding aptitude, and was rewarded (as is still the case in Russia) with a prescription of seven hours’ practice a day, every day, for the rest of his boyhood.

Playmates and playtimes were relegated to a very distant second place in his life. Yet he expresses few regrets and no resentment. “I believe you don’t succeed at the highest level if your life is just pleasant,” he told me. “Life was hard in Siberia, and my musical education was just as tough. But the result was that I learnt the whole language of violin playing in just over a year.”

The rest is the stuff of legend. At 5 he played his first recital, including a Paganini piece that would tax most conservatoire students. At 15 he won his first big competition. Unlike earlier Russian superstars, the boy Vengerov — a “child of perestroika”, as he puts it — could reap the rewards without petty state restrictions. The family, who are Jewish, emigrated to Israel, and his global career was launched.

But he’s now 32, and the critics have not been uniformly supportive of the glamorous boy wonder in his adult years. Because Vengerov, following in the great showman-fiddler tradition of Jascha Heifetz (whose bow he has inherited), loves to wow the crowds with outrageous 20-note-per-second encores, because no gala in the Western hemisphere is seemingly complete without a scintillating turn from Maxim, and because (following the example of his two great musical “godfathers”, Barenboim and Rostropovich) he is said to charge the highest fees in classical music, the impression has grown that Vengerov is all silky style and no soul.

I don’t believe that’s true. I think his critics are mistaking a sunny disposition for superficiality. But as if to prove his serious credentials, Vengerov has engrossed himself in projects that lead him off the narrow track usually trodden by virtuoso violinists.

Ten years ago, inspired by his mother (who, he says, “literally took children from the streets and brought them up in her orphanage to be wonderful human beings”) he became an honorary Unicef ambassador and has travelled widely, playing to children who have lived through appalling times, particularly in Africa. “For me the greatest aspect of being a musician is being a good human being,” he says. “In Uganda and Sudan I have seen traumatised children — victims of horrible things — with whom you couldn’t communicate, even if you spoke the same language. But when I started to play, they started to dance.”

Another diversion was to study the Baroque violin for two years, relearning his technique from scratch in his twenties, when most soloists consolidate their careers. “My friend Trevor Pinnock [the English harpsichordist] inspired me to take it up,” he says. “What it taught me was to use less of my own muscles. You have to let the instrument play. You can’t force the tone, and if you use too much vibrato it kills the string. It opened a new sound dimension for me.”

Now comes another “broadening” project: an EMI Classics recording of Mozart violin concertos on which Vengerov not only plays the solos but conducts the band, the brilliant youngsters of the UBS Verbier Chamber Orchestra. “It was a collaboration between young souls hungry to explore the depth of Mozart,” he says. “The youngest player on the CD is 17, the oldest is me — 31 at the time. I hope Mozart would have approved, because he was about 19 when he wrote these concertos.”

And Vengerov has another extraordinary project in the pipeline. Inspired by jazz fiddler Didier Lockwood, he has been studying electric violin — which, though bowed and fingered like a conventional fiddle, offers the player a similar range of “extras” as an electric guitar does, from artificial reverberation and echo to fuzz and wah-wah effects.

Not content with acquiring this new technique, Vengerov has also been learning to tango. Now he is touring what sounds like a weird new work that brings these skills together. Benjamin Yusupov’s Viola Tango Rock Concerto , it transpires, is exactly what its name suggests “I start on the viola, then switch to electric violin, on which I improvise rock-style. Then finally I dance a tango with a partner. I think the piece makes a powerful statement about different cultural influences at the start of the 21st century.”

Indeed. Perhaps Yusupov should have called his work Strictly Come Fiddling . But is Vengerov as charismatic a dancer as he is a violinist? “Come and see! I am doing it at the Albert Hall in August. Of course, to become a proper tango dancer takes years of study — it’s as hard as learning the violin. But I am taking this challenge seriously.”

Mozart Concertos is released on Monday. www.emiclassics.co.uk Maxim Vengerov is at the Barbican, London WC2 (0845 1207550), on May 11

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