Maurizio Pollini is getting almost chatty these days. I first met him 20 years ago in his Milan apartment: part of a Renaissance palazzo, pristine white, exquisitely furnished. He was courtesy itself. Yet while his wife, as extrovert as he is insular, played with their son in the next room, I found myself spouting what was virtually a monologue in order to extract the odd precious monosyllable from the impeccably suited figure opposite.

Par for the course, I later discovered. Pollini might well be one of the greatest pianists of all time but, as far as interviewers were concerned, he has been an impenetrable enigma. For some concert-goers, too. There are morticians who go about their duties more chirpily than Pollini on the concert platform.

Yet at 65 he seems mellowed, relaxed, prepared to offer whole sentences, even short paragraphs, in reply to questions he deems interesting. He’s in London for two reasons. The first is to play two Beethoven concertos – the Emperor and the Fourth – with the London Philharmonic (the latter performance, on October 7, marking the orchestra’s 75th anniversary). The second is to take part in the South Bank’s celebration of the avant-garde Italian composer Luigi Nono, one of Pollini’s closest friends until his death in 1990. That concert, on October 31, will include . . . sofferte onde serene . . . – an astonishing work for piano and electronic tape specially written for him.

Few pianists of his stature bother with late 20th-century repertoire at all. It’s incredibly hard to play, and leaves a lot of music lovers cold. But Pollini has always championed it as both a duty and a pleasure. I once watched him perform Boulez’s stupendously complex Piano Sonata No 2 – from memory. Another of his favourite feats is to pair Beethoven’s monumental Hammerklavier Sonata with the coruscating note-clusters of Karlheinz Stockhausen’s Klavierstück X, for which he ceremonially dons a pair of protective gloves.

“Why not play music that has so much beauty?” he asks. “Boulez’s harmonies, for instance, give me joy. It’s just a matter of making audiences familiar. What we need is action by the majority of musicians to present this repertoire so regularly that it becomes a normal part of musical life.”

But what puts people off, I say, is modern music’s complexity. He will have none of that. “Complexity exists in music of all ages,” he points out. “Medieval music, by composers such as Ockeghem, is very complex. Beethoven’s Grosse Fuge was written to very strict rules. That didn’t stop those composers from expressing their emotions. What matters, whether it’s classical or contemporary, is for the performer to make the sense clear: the necessity of the notes.”

Few performers reveal that “necessity” with such mesmerising intensity. The cascading brilliance of Pollini’s Chopin fizzes through the listener like a drug. Yet one emerges from his performance of, say, late Schubert like the wedding guest from the clutches of the Ancient Mariner: sadder, wiser, and stunned by a storyteller who stares unblinking into the abyss of death.

In part his stupendous technique accounts for the impression he makes. He can sight-read virtually anything, and has a unique sound: crystal-clear and entrancingly pure. “For me the challenge of the piano is that it is essentially a percussion instrument,” he says. “Yet it is possible to create the illusion of singing a sustained melody or commanding the resources of a whole orchestra.”

He’s also an uncompromising perfectionist. Barbican audiences should thank him for that. It was his refusal, back in 1983, to play a recital until 2,000 cosmetic balls were removed from the ceiling that triggered the first steps towards improving the hall’s acoustics.

But Pollini has two other invaluable qualities: acute intelligence and scrupulous taste. The roots of both probably lie in his background. His father was one of the leading Italian rationalist architects; his mother a fine singer and pianist; his uncle the sculptor Fausto Melotti. The Pollini home was one of those extraordinary hothouses where artists, musicians and writers came to chew over the latest ideas.

The boy Maurizio absorbed all that, and showed himself precociously gifted. He was giving recitals at 11. Nobody who knew him was surprised when, at 18, he won the 1960 Chopin Competition in Warsaw, the youngest of 89 competitors. “That boy plays better than any of us,” said Artur Rubinstein, who was chairman of the jury and later became Pollini’s closest mentor.

Maybe, but the boy was completely unprepared for fame. What followed were nightmare years, marked by illnesses, cancellations, chronic nerves, feverish interpretations. “The impression left by his playing,” The Times sniffed about his London debut in 1963, “was that he was due to catch the 9.05 from Waterloo.”

Pollini disappeared from the concert scene, studied philosophy and played chess. When he reemerged, in the late Sixties, he seemed to have wrapped all the nerves, the shyness, the inner man, in a protective shield of stupendous pianism.

Today? He long ago cut his schedule to about 40 concerts a year, for which he receives astronomic fees (though, in the quixotic tradition of Italian socialism, he reputedly gives half to his piano tuner). He drives fast cars (an accident broke his back but miraculously left his fingers intact) and pumps nicotine and caffeine into his body on an hourly basis.

He hates what has happened politically to Italy. “But what really matters,” he says, “is that I feel more exhilarated by music than I have ever done. And I am still capable of surprising even myself.”

The bright brigade

Simon Trpceski Wonderful young Macedonian plays Ravel’s Piano Concerto in G with the Philharmonia and Charles Dutoit, RFH, Oct 18

Barry Douglas The Ulsterman packs a punch in the big Romantic warhorses. Playing Brahms’s First Piano Concerto with the Royal Liverpool Philharmonic. Philharmonic Hall, Liverpool, Oct 25, 28

John Lill Veteran British pianist tackles Shostakovich’s Second Piano Concerto with the Hallé. Bridgewater Hall, Manchester, Oct, 17, 18, 21

Steven Osborne Superb British pianist playing Debussy, Beethoven and Rachmaninov, QEH, Oct 17

Maurizio Pollini plays at the South Bank (www.southbankcentre.co.uk, 0871 6632583) with the LPO on Wed Oct 3 and Sun 7, and as part of the Nono festival on Wed Oct 31, 2007

Explore Music

• CD Reviews

• Live Reviews

Editor's choice

• Exclusive: Listen to AC/DC's Black Ice
• Burning Bush with W
• Boy George on sex, drugs and Amy Winehouse