Nigel Kennedy's return reminds us of his musical genius, writes Chris Maume
The good citizens of Vienna were elated but perplexed as they filed out of the Golden Hall in the ancient and stately Musikverein. They had just witnessed a bravura performance by a master violinist, but there was a measure of wry Austrian clucking going on, mostly featuring the epithet "Mother fucker". It would appear that Phase Two of Nigel Kennedy's illustrious if unconventional career is well underway.

Since its fin-de-siecle golden age, the city of Beethoven, Schubert, Mahler and Schoenberg has been buffeted between the superpowers who saw off the Hapsburgs, becoming a city of ghosts, a beautiful irrelevance, a theme park to rival Britannia Towers. Kennedy (he's dropped the christian name), was here to pay homage to one of the city's guiding spirits, launching his new album of works by Fritz Kreisler, the violinist who achieved the kind of crossover fame that only the likes of Kennedy himself has emulated. He packed venues such as the London Palladium, sold out provincial tours and recorded popular versions of hit tunes. Reports that he sported a mohican are unconfirmed, however.

Kennedy's story is well documented - hot-housed unhappily at the Yehudi Menuhin school, prevented from joining the Duke Ellington band at 15 and sent instead to the prodigy-by-numbers Juilliard school in New York. Left audiences ravished by his playing, purists enraged at his antics, released the two million-selling Four Seasons, inspired the classical revival along with the Three Tenors, then tired of the Baroque 'n' Roll circus, retired for five years to return in triumph last year.

One of the prime movers in the backlash that preceded his retirement was a speech by the then Controller of Radio 3, John Drummond, who called him "The Liberace of the Nineties". But part of his appeal to non-purists was the grungy, Sid Vicious feel that hung about him, and he took the Golden Hall stage for an afternoon press conference in scruffy leather jacket and oval shades. With his padding, shuffling gait and his post- punk coxcomb, he looked as if he should be selling the Big Issue rather than facing the world's press. Frankly, we were expecting a bit of a prat, but it was difficult not to warm to his emotional transparency and his passion for music. He spoke slowly and deliberately, with few contractions, enunciating each syllable as though desperate to be understood.

As he spoke about why Kreisler means so much to him, he could have been talking about himself. "His playing was the antithesis of the Juilliard school, and that's got to be good. Artists are stamped out by formula, it's the enemy of creative music-making. Artists of a sensitive talent have it extinguished and replaced by tricks."

When a "cat in the blue shirt", as Kennedy referred to him, asked whether five years away had helped him mature as a person as well as a musician, he railed against the notion. "That's a very dubious statement. Evaluating your own maturity is itself immature. This whole maturity thing - it's a shocking concept. Musicians have to be vulnerable, open. Maybe children are better at doing that than adults. Maybe a musician has to be childlike." At this point, the man from Reuters lent over and whispered "They've got it wrong. This man's a star."

Then Kennedy got up and seduced us completely with a soaring rendition of Bartok's Romanian Folk Dances. Afterwards, as he signed autographs for a patient queue of hacks, he gave his pounds 750,000 fiddle to the EMI press officer to hold. She examined it intently. "What, is there some shit on it?" he asked her. "Has it got wood lice?"

EMI was out in force at the Musikverein that evening for Kennedy's Viennese debut. With sales in a downward spiral that was interrupted only by the boy himself, classical music needs this urchin who plays like an angel. He had smartened up from the afternoon, and in a white shirt, silver waistcoat and white trousers held up with a black scarf, he looked merely bohemian rather than Swampy's older brother. Ever the pretend rock star, he kept us waiting, if only for 20 minutes, before hurling himself into a riveting account of Bach's Sonata Number Three. It should have felt cerebral and austere but it was visceral and extravagant, exquisitely at home amid the floor-to-ceiling gilt, the angels and cherubs and the bare-breasted women who once caused Bruckner to avert his eyes in embarrassment.

In the second half there was Kreisler's String Quartet in A minor, which he recorded in 1935 at Abbey Road with Kennedy's grandfather, Lauri, playing cello, then a string of tumultuously received encores. It was at this point that you began to wonder if this holy fool is as much idiot as savant, as he launched into a series of viola-player jokes - "What's the similarity between a viola player and an Iranian terrorist? They both fuck up bowings," for example. There was also one, lost to the Kennedy diction, about scud missiles and Jews, that I was glad I couldn't hear properly. "Oh God, he's losing it," I muttered, staring at the floor in embarrassment. Then he played, and everything was fine.

There was some consternation over bad language later on at the Porgy and Bess club, too, as I explained the phrase "full of shit" to a Korean journalist. Kennedy had been due on at midnight, although at 12.30am he was still signing autographs at the Musikverein. But he was on by 1am with his eight-piece band, back in his traveller's gear and well into his "Hendrix: Concerto in Suite Form".

Over the next two and a half hourswe were treated to a dazzling array of musical textures and associations. He's a fine conductor, too, leading the band through semi-improvised passages with the rapt expression of someone feeling the music with every cell of their body. With no overbearing ego and all that talent, you felt - even at 3.30am, after one frothy Viennese beer too many - that you were in the presence of a maestro.

And after the gig, the band played on in his hotel room until the last of them had fallen asleep at 6am. I have this image of Kennedy, standing in his room surrounded by comatose bodies, fiddling away as the sun rises...

'Kreisler' is on EMI Classics.