It may be otiose to say so but I tell him that another strong impression I took away from his London cycle was that playing the piano is still an immensely pleasurable activity. "I still enjoy playing very much. And it's more necessary than before to give myself the conviction that I do what I'm doing out of choice and not out of some other pressure: as you grow older and your physical resources start to be more limited, that necessity becomes bigger. It's a way to survive well and I hope my physique will allow me to go on for a while yet."

Oh, but surely, I murmur ... and he does look very fit, though I'm aware he has had a problem that affects many tall people. "Well, you know in the last three years I've had trouble with my back, and I have to cope with it and that means I have to stop playing the physically biggest works; and to stop playing the Hammerklavier Sonata was a big sacrifice. I have lived with this piece since I was 21 and it was one of the pieces that made my career in many places. But a redeeming feature -- if I may say something personal about my own recordings -- is that I found a live recording of the Hammerklavier which I did at the beginning of this year in Vienna, which will come out as part of the new cycle of the sonatas, and which I feel is a decent way of leaving the piece. And there's another live recording of the work, from my London cycle of 12 years ago, which has been available on CD -- but unfortunately not in a good transfer to digital sound -- and which will now come out again, in a special 25-CD box, with improved sound: so there'll be two live performances of the Hammerklavier to compare! There are not many live performances that one is able to use in this way, but I'm particularly glad that with such large, exhausting works there have been some, over the years, which show that I've got through. Also in the 25-CD box there is the live Diabelli Variations, from nearly 20 years back."

We talk about developments in recording: the live recording of concerts continues to be important to him but his studio sessions no less so. The essay in his book, Music Sounded Out (Robson Books: 1990), summarizes what he perceives to be the advantages and problems of each. The fanaticism of 'either-or' is foreign to him, and like all fine artists who really know what they're doing he is briskly practical. "Basically, I want to play as 'live' in the studio as I do in the concert-hall, but with the advantage that I can listen to a playback and that I can play more than once; and that also if I find the performance good enough but four bars not good enough I can insert these four bars without playing the whole damn thing again. And the wonderful thing about the studio is that you can reconsider details, provided you have a concept of the whole. If you haven't, it's much more difficult!

"Yes, technology has greatly changed. I'm not somebody who's easily persuaded about the merits of digitally recorded sound. Sometimes I've felt that I would rather go back to analogue. There are cases where I've found that the old tapes with their slightly dusty sound are more natural than the digitally recorded and all-too-clean sounds that were considered more realistic. The walls of a good concert-hall have also a certain amount of patina, of dirt, which contributes to a pleasurable impression. But I do think things have now advanced, that the engineers now know how to use digital technique to better advantage, with warmer sound.

"And there was really progress, I felt, when I started this Beethoven sonata cycle: there was a new computer which was put up in another room, with an engineer following my performances and my specifications of takes and putting them together on the computer directly, in digital sound, and I could listen to them as soon as I wanted and react to them on the spot. So my first recording of the series, of the Op. 31 Sonatas, was completely finished only a few days after the recording session. And of course the advantage of DAT cassettes is that you can store the takes numerically and if there's a doubt about something retrieve them so quickly. As to my aim in the studio, first and foremost it's to please myself as much as possible when I listen to the playback, which in the end rarely happens, and five years later I may change my mind anyway. But it's good to be able to listen to the edited version there and then and if necessary re-do an entire movement."

Brendel began to make records when he was still quite young. They announced him as an important musician, but he had gifts in many directions and in those early days, before Vox asked him to record all the solo piano works of Beethoven, I think it was not to be predicted exactly what kind of pianist he was going to be. Liszt, Busoni and the Schoenberg Concerto were already there, Mozart and Schubert too, but, like a journey through a Schubert sonata, it was possible to feel as one followed him that different turnings might have been taken at various points. Or is that to look back now with over-fanciful hindsight?

"I'll tell you something: when I recorded the C minor Beethoven Concerto in, I think, 1959, it was my first performance of it ever. When I recorded the Diabelli Variations for Vox, it was my first performance of it ever. One sometimes has to take risks! On the whole I would not recommend it, certainly ... and yes, in my case I've been lucky enough to re-record pieces.

"As to late Beethoven, I don't think it's necessary for every young artist to record Op. 111 as his or her second record. But to speak personally: as I was composing when I was young and was interested in new music and trying to produce new music myself, I felt much closer to the late sonatas than to the early ones. The early sonatas dawned on me much later, and then later still it dawned on me that my first relationship with the late ones had not been particularly satisfactory.

"But there you are. There is advantage and disadvantage in trying to scale those peaks early on. The advantage is that if you learn a piece like the Hammerklavier Sonata when you're young it stays in the memory. If you learn the 48 [Preludes and Fugues from J. S. Bach's The Well-tempered Clavier] early in your life you'll have a better chance to play them late in your life. The disadvantage is that you necessarily get used to certain fingerings in such complicated pieces which you don't easily get out of your mind again, or only with a certain amount of danger, and you have to live with them and make the best of them. You could find much better fingerings later on but the old ones are stored deeply and in a moment of tension, or nervousness, the old ones resurface. In a way, when I learnt the Diabelli Variations in my thirties it was a very good time, and I think I continue to play those fingerings with a certain amount of pleasure!"

We talk of the Diabelli Variations and recall how 30 or 40 years ago they were so rarely played -- "whereas nowadays nearly every young pianist throws himself or -- no, not herself really: I'm just trying to think, I've not heard a woman play them, have you? -- which in a way is amazing, isn't it? Why shouldn't they? I don't see any reason why they should not." Reflection later brings to my mind very fine broadcasts of them, years ago, by Edith Vogel and there must surely have been one or two recordings since, but Brendel is right: the Diabelli Variations, so far, do not belong to the territory of equal opportunities.