"In spite of all the pats he received on his back, Uday Shankar was not happy. He was not satisfied with the Hindus' music played by a Western orchestra for his dance. He felt the need for Indian musical instruments to lend authentic and accurate rhythm to his dancing" – Ram Avtar, History Of Indian Music And Musicians.

The year was 1930 and Uday Shankar, Ravi Shankar's glamorous elder brother, was taking Europe by storm as a dancer. After studying painting at London's Royal College of Art, Uday produced Indian drama and ballet for the first time in London and Paris, even dancing opposite ballerina Anna Pavlova in the Radha Krishna Ballet. In order to present Indian music more authentically, he brought over a group of Indian musicians, including his ten year old brother Ravi, and formed his own company, which toured America three times in the next four years. More enthusiastic pats on the back from American audiences, who perceived Uday as a potential screen idol to replace the late Rudolph Valentino. And thus began the international career of Uday's little brother, Ravi Shankar, the one and only Indian musician to become a household name in the West. Now celebrating his 76th birthday, Ravi Shankar is on the phone from New Delhi, and I ask him if this unique position makes him feel a special responsibility.

"Exactly! I've been very conscious of this. If I had taken advantage I would have been a multi-millionaire – the raga rock king! But I stopped at a certain point, as regards playing with Western musicians like Yehudi Menuhin or Jean Pierre Rampal. I have never tried other styles of music. It has always been a case of composing a piece based on Indian scales and rhythms. And if I played with Japanese musicians [Hozan Yamamoto and Susumu Miyashita on East Greets East, 1978], I was taking not a raga, but a modal structure which resembles our ragas, and composing on that basis. So I felt at home."

In 1966 George Harrison took sitar lessons from Shankar on a houseboat in Kashmir. Shankar's celebrity rocketed in the West as he played the Monterey Pop Festival in 1967 and Woodstock in 69. I ask him about the criticism that resulted in India, the charges that he was 'Americanising and jazzifying' Indian music.

"I have two different approaches: one is as a performer on the sitar, and the other is as a composer, trying to experiment, to create something different based on our classical or folk music. There are some snobbish people here, who talk of tradition all the time, and they think I am committing sacrilege. But this happened much more in the past. Now I am lucky because I have been accepted as what I am. When I perform on my sitar I am very traditional, very orthodox, but within the framework of our tradition I have done a lot of new things. Indian music has never stood still. For thousands of years it has developed, so slowly, so gradually that no one realised it was changing. Nowadays the changes are very fast, so some people get overly worried, but Indian music is absolutely a living tradition."

Harrison and Shankar have compiled a 4CD overview of Shankar's colourful career, titled In Celebration. As well as stunning traditional improvisations on sitar, it contains several duets with Western classical musicians. I ask Shankar if these performers' total lack of improvising background made musical communication difficult.

"Ah, but I didn't expect them to improvise. I wrote the parts down for them. I always improvised my own solo parts, including the Sitar Concerto with symphony orchestra. But when I was connected with the group I always had to have fixed parts."

Shankar has always gone to great trouble to stress the spiritual content of Indian music, and was distressed in the 70s that his music came to be associated with rock exoticism, drug cultures and dropping out in general. Is there a connection between this spirituality and the act of musical improvisation?

"I can't think of music without any spiritual aspect. An oud improvisation of course… well, it's like uttering a fixed prayer or mantra. When you really communicate with God through meditation, or whatever method you have, you don't always stick to mantras or fixed prayers. Mantras are of course one way of meditating, they are fixed things. But when you really go free and you have that devotional quality, you pray person to person with that supreme power or God. It is the same way with music to me."

Can you find this spirituality also in Western music? "I find it very much there up to the Baroque period, when music was still connected with the church. Also later, in some passages it comes over very strong. Of course it becomes less and less, because it is not only composed as music, but also calculation."

There has, of course, been a mass upsurge in the West of music that tilts towards what might be defined as a calculated, or processed, spirituality; from MTV Unplugged and Franciscan monks in the Top Ten, to the sense of a spiritual dimension opening out of the quasi-religious communal experience of raves and dance music festivals (not to mention the Goa Trance caravan).

"Whatever I say about this has to be very personal," says Ravi when I put this phenomenon to him, "I cannot say anything about what others are doing; but I have always been confronted with this same thing that you are saying. Ever since I first travelled to the West on my own as a sitarist in 1956, I have met people who have become such fans of Indian music, and invariably they tell me how it has changed their lives because the music is so spiritual. Music has mostly become part of entertainment, whereas in India for centuries we have had a definite background that has been taught to us, always emphasising the spiritual aspect. That's why it is not an effort, but something which comes out naturally."