The G-string man

Jacques Loussier is a man who defies category. He has accompanied Charles Aznavour and played with Romanian gypsy orchestras in Paris, recorded a mass with the great English counter-tenor James Bowman, written his own variations on Bach, Vivaldi, Handel, Debussy, Satie and Ravel, and has accused Eminem of sampling his music without permission.

Those who know Loussier only through his most famous piece – his trio's version of Bach's Air on the G String, used since 1962 in the Hamlet adverts – would never guess the depth or breadth of his work; the Hamlet ad uses only the statement of the main theme, cutting out both Loussier's introduction and the later development. In defying categories, however, the French pianist has often fallen between them. The jazz world has never embraced him, even though the double-bassist in his original trio, Pierre Michelot, had a distinguished jazz career recording with, among others, Dexter Gordon. And in classical circles, for whom tinkering with Bach is sacrilege, his name is often greeted with a curled lip.

All this leaves Loussier unmoved. The seeds of his sound – classical themes set in a conventional piano-bass-drums jazz trio – sprang unsown when he was 10 years old. "The first piece of Bach I came across, maybe six months after I started learning, was the Prelude in G minor," says Loussier. "I simply fell in love with this piece. I played it 100 times or so. Then one day, I started to change the melody, then the left hand harmonies. It was a natural instinct."

What he was doing, albeit tentatively, was to improvise. "When I went to the Conservatoire in Paris, there was a canteen with a piano. My fellow-students would always ask me to play some Bach with my improvisations. At that time, the Modern Jazz Quartet was doing this thing already: I heard them and that gave me the idea to transform it with bass and drums."

Nearly 10 years later, in 1959, he released his first recording with the Play Bach Trio. "It was a success straight away. First of all, I just thought I was going to make 20 copies for my friends. I never thought it would be of great interest." But it was, and as well as becoming one of the quintessential records of the early Sixties, it immediately attracted a critical backlash from the classical establishment. Even today, this bemuses Loussier. "They said we shouldn't be doing this with Bach. But my instant reply was that Bach himself was improvising on these pieces for many years."

So he was. Most proficient church organists today still have this skill, although they usually refer to it as extemporisation instead, and it tends to be used as a gap-filler – when the congregation is filing up to take Communion, for instance – rather than something to be displayed. But they are virtually alone in the classical world. When Yehudi Menuhin performed with the jazz violinist Stéphane Grappelli, he was unable to conjure up his own solos; they had to be written down for him. This baffles Loussier. "I don't understand why the art of improvisation has been lost. It should be part of what a musician does. In a concerto, the cadenza is there for the musician to show how he is inspired by the spirit of the music. But 99 per cent of classical musicians are not able to improvise. So they just write down a cadenza, or play the original, which is a pity."

To be fair, it's not just the tinkering with Bach that upsets some, but how he tinkers with it. Some tunes are treated respectfully and solemnly. On others, such as his version of Wachet auf, his habit of playing the recapitulation of the melody at double speed is unintentionally hilarious. There's no doubting his technique, though, or his ability to take well-known themes such as the Fugue from the Toccata and the Fugue in D Minor and swing like the clappers. His popularity with, on the whole, a rather middlebrow audience, has endured, and he regularly tours in Europe, North America, the Far East and the Antipodes.

After the first Play Bach trio, he took time out to record electronic albums, including Pulsion, of which more later. In the late Nineties, he returned to Bach, and applied his concept to other composers from the baroque and impressionist eras. It was one of these recent recordings that he thinks caught the ear of Eminem, or if not him then someone in the foul-mouthed rapper's camp. "I had never heard of Eminem before in my life," he says. "My son told me, 'Papa, he has certainly used your music on the track "Kill You" – it is four minutes 25 seconds exactly of Pulsion. You should listen to it, it's your music."

So, no doubt to the amusement of the managers of his local record store, the distinguished, reticent figure of M Loussier went out and bought the album. "It's exactly the same tempo," he says. "The same figures, the same harmonies, the same repeated sections."

Loussier's lawyers are looking into the situation, although as yet they have had no response. The pianist thinks that they must have heard his music not on the original album, which has been deleted, but through a recent Bach album. "I used the Pulsion theme in the middle of the improvisation on the Gavotte in D Major. I suppose they must have thought it was Bach's music, not mine. So they used it without asking permission. If they had come to me, I would have accepted, and allowed them to use it for nothing, but they didn't, which is not nice."

That's not to say that Loussier is angry about it. Having bought the CD to check whether his music had been lifted, he went on to listen to the rest of it. "There is something in this group, Eminem," he says. "They're not interested in the music, they're interested in distributing words and feeling. There are some very strong pieces." This typifies Loussier's approach to other kinds of music. He is determinedly non-judgemental, declaring: "I like good music whatever it is." A few months ago, speaking on the phone, he put it in a particularly charming way: "Who is to say what is good and what is not? God is not with us." It is part of a life-view for Loussier. "Generally, I don't like rigid people, it is not necessary to be rigid. It is better to be able to understand. The world would be in much better shape if people were more relaxed and accepted their differences."

Although he doesn't seem to share the traditional Gallic obsession with food, he uses a culinary metaphor to sum up his philosophy: "If you don't like it, you are not obliged to eat it." Handel is the new item on the Loussier menu, while his kitchens are preparing to dissect Beethoven for a forthcoming project. Many find that a small meal of Loussier is enough, and his entrenched critics will always find him unpalatable. But to beginners, I would recommend his version of Bach's Prelude and Fugue in C Minor. You may well find you develop an appetite for this charming Frenchman's cuisine.

'Handel – Water Music & Royal Fireworks', Jacques Loussier Trio, is out on Monday