I first encountered Ferruccio Busoni in the early 1920s. I met him several times and heard him play a lot. Outstanding impressions were the Beethoven Hammerklavier, the Liszt Sonata and his own Fantasia contrappuntistica. I also heard him play nine of Mozart's concertos in Berlin shortly before his death, as well in Beethoven's Emperor – his last public performance. That left a tremendously strong impression on me, though I couldn't really say why. I was not quite 20, and I had not begun to listen analytically. So it's the impressions that come back. Mostly it was just the incredible strength of his personality and his musical imagination.

Busoni died in July 1924. Audiences were crazy about him during the last three years of his life in Berlin. He had always been a charismatic figure – an incredible beauty, regal in stature. Of course, as a composer he also held tremendous sway. All the young composers were under his influence and revered him. He was unique: a creative interpreter.

So many factors have to come together in order to produce a great interpreter. Busoni had this incredible vitality and his sense of rhythm was extraordinary.

That's one of the things I remember from his playing: the incisiveness of his rhythmical feeling. Another thing was his incredible brio and drive and passion. And, of course, he was entirely unconventional. He shocked everybody. He shocked all the academic circles in Berlin. They would cry, ‘That's not Mozart! That's not Beethoven!’ Yes, he would shock you, but the next minute you were floating with him, because his playing had such conviction, such genuine feeling. He did everything his way! He was free in everything: in rhythm, in rubati. He did whatever came into his imagination, without scruples.

The only thing I didn't like too much was the way he played Chopin. He played the Preludes many times, and it was a little too far away from what one believes to be the right Chopin style. Of course, it was technically fabulous.

I remember the B-flat minor Prelude was hair raising! The power of the fingers and the crescendi were incredible! But he also gave it something that I think is not quite in the music: too much intellectual and metaphysical meaning. I don't think these elements are in Chopin's music to quite that degree. There's a recording of the Etudes which is fantastic technically, but Busoni ruins the music. Towards the end of Op 25/5 for example, he introduces octaves and plays three times more slowly than marked! It's not something I can accept.

I think he was at his greatest in Liszt and Beethoven, although these days people would probably regard his Beethoven as being too free. He played one of Beethoven's Eccossaises in his own arrangement as an encore at every concert. It had absolutely nothing to do with Beethoven. It was sort of a joke. His repeats are fantastically fast! He didn't play Schubert or Schumann or Brahms. He hated Brahms and thought that he was a bad composer – music for the bourgeoisie.

Another criticism I have of Busoni is that he would rearrange a composers' written score – for example he would fill in voices and double up various parts. It's one of the things I wouldn't have liked if I had known as much in those days as I know now. But his personality was so strong. This phenomenon, Busoni, was so incredible that one accepted from him the things that one wouldn't have accepted from anybody else.

His approach to cadenzas was especially daring. I have them all and I know them quite well. He said there were two ways of composing a cadenza. Either in the strict style of the composer and his era, or commenting on the music of the composer from one's own era and individual feelings.

The cadenzas in the Mozart concertos are actually original compositions of Busoni – extremely interesting. I think they are fabulous, but shocking. At first you have the feeling that they have nothing to do with Mozart but then, and only in a roundabout way, you gradually feel the connection.

The compositions by Busoni that I would play regularly included the Indian Fantasy for piano and orchestra. I also performed the Konzertstücke and the Concertino for piano and orchestra. I think these are better than the Concerto, which is a rather early work and is really eclectic – full of things that remind one of other composers.

© TULLY POTTER COLLECTION

His works fell out of favour after the war, but they were being played a lot in the 1920s when I first encountered him. His operas were performed in all the opera houses in Germany: Die Brautwahl, Arlecchino and Turandot, plus of course Faust. In those days in every pianist's programme there was always some Busoni – unfortunately too often those Bach transcriptions.

I always say the ideal point of interpretation is when 50 per cent of what is happening is, so to speak, the blood of the interpreter and 50 per cent the world of the composer. By that I mean the composer and interpreter coming together in a full, 100 per cent relationship. There are many interpreters who have 30 per cent of their own and 70 per cent of what they think is the composer. In Busoni, I think you could say there was 70 or 80 per cent of his blood with very little of what might be termed the composer's intention. The academic world would never accept that today.

His interpretations always had this quality of creative improvisation. I heard him play several pieces many times and it was always different – very different. Much more so than with the usual interpreters. In the 19th century and the beginning of the 20th century, people believed in the power and importance of individual development and the individual. One aimed to develop one's individuality as an interpreter 100 per cent. Today, people look askance at somebody who has a very developed individuality.

Busoni made a point of emphasising his individuality. He didn't care what people thought of him and he didn't court popularity. He tended to say things that shocked everybody. Not for the sake of it, but because he always sought to speak whatever he thought was the truth.