And the toast is Slava!

Mstislav Rostropovich (Slava to his friends) will be in town on Saturday for a series of concerts to celebrate his 70th birthday. Edward Seckerson met the cellist, conductor and catalyst for musical innovation at his Paris home, where they spoke about realism and escapism under the Soviet regime, the pros and cons of live recording, and the price of sausages

Slava! An exuberant greeting, a bear-hug, a triple-kiss all rolled into one explosive little word. It's the nickname by which the great Russian cellist and conductor Mstislav Rostropovich is universally known. Leonard Bernstein added the exclamation mark when he composed his Slava! overture - a very personal, very feisty tribute to a dear friend - and even that somehow belongs, is somehow inseparable from the name, the man, and the musician whose larger-than-life persona is one big exclamation. Someone underlined his name in the great scheme of things. He is Saint Cecilia's most famous, most irrepressible dissident.

On Saturday night, at the Barbican Hall in London, Slava and the London Symphony Orchestra will be signing on for a series of concerts in celebration of his 70th birthday. Bernstein's hale and hearty overture will, of course, take pride of place - a musical toast, the only toast that Slava doesn't make in vodka. Slava! - the overture - is "fast and flamboyant". So, too, the man. We meet in Paris. He arrives, as ever, in moto perpetuo. His lavish apartment on the exclusive Avenue Georges Mandel is one of nine homes that currently satisfy his status as "a citizen of the world". Ever since 1974, when the Soviet authorities "erased" his name (and that of his wife, the soprano Galina Vishnevskaya) from their conscience (his public defence of Solzhenitsyn was the final chapter in that particular saga) he has, he says, "belonged" to no one nation, but rather to all. He remains "the Russian musical conscience in exile", but has so far resisted all attempts to return his passport. So long as the hammer and sickle are symbolically emblazoned on its cover (government sources insist that the reasons are purely economic - that a re-design is simply too costly) he will continue to do so. But never be in any doubt that his soul resides in the bosom of his countrymen, that his cultural roots go down deep in Russian soil.

On the day that we meet he is "in transit" between St Petersburg, Taiwan, and London. The Paris apartment is belle epoque with the look of a Byzantine museum. Precious Russian artefacts occupy every available space: all that glitters is gold, and silver, and mosaic. I gather that he has now added "a palace" in St Petersburg to his list of homes. Is that significant? Only inasmuch as he is forever "optimistic" for the future of Russia. When he joined Boris Yeltsin on the barricades during the attempted coup of August 1991, he feared for his life but knew in his heart of hearts that there was no going back, only forward. Rebirth is slow and painful, he says. But we must be patient. The next generation will make the difference. Russian towns and cities are reverting to their ancient names, but the attitudes are new.

The irony is not lost on him. The so-called "artists" who "reproduced Mr Brezhnev's portrait", the thousands of bad composers who fleeced the Ministry of Culture for "terrible music in praise of Lenin they should have been paid not to compose!" - their days are gone. But the old ways die hard. "Old ladies come to demonstrations with red flags and portraits of Stalin. Fifty years ago, many of these same old ladies lost friends and loved ones to the Stalin regime, but now all they care about is the price of sausages! They have such short memories."

Slava's memory is long. And detailed. And selective. It needs to be. EMI are about to issue a 13-CD edition entitled Rostropovich - The Russian Years, 1950-1974, a treasure-trove of hitherto unreleased recordings, many live, chronicling the extraordinary period from his auspicious beginnings to his ignominious expulsion - and including many of the works composed especially for him (the current tally is somewhere in the region of 90). Each performance tells a story and each story has its own particular resonance. To hear them again, says Rostropovich, is to relive all the emotions, the anticipation, the nervous anxiety, the elation of each specific occasion. Like the world premiere of Prokofiev's Sonata in C for cello and piano which he and Sviatoslav Richter gave in March 1950. Rostropovich, then aged 23, was the dedicatee. Two years earlier he had made an indelible impression on the composer with a performance of the 1938 Cello Concerto, albeit in a reduction with piano accompaniment.

Prokofiev was in the audience: in the front row - or so Rostropovich thought. Without his spectacles, his eyesight was fuzzy at best. So he played encore after encore for the bald-headed gentleman he assumed to be the composer, gratefully acknowledging the applause with reverential bows in his general direction. After the fourth encore he left the stage only to be confronted by another bald-headed gentlemen who impatiently enquired how long he intended to go on playing. He had a proposition to discuss. Would the young Rostropovich join him at his dacha to help in the revision of the concerto. And so the Sinfonia Concertante was born, tailor-made for a brilliant protege.

Stories like this one take on an extraordinary immediacy coming as they do from an artist who was/is the hotline to so many composers. If they lived (or even if they didn't) during the past 70 years, Slava knew them, inspired them, brought them together. You want to know how Shostakovich reacted to the world premiere of Britten's Cello Symphony (Moscow, 1964, under the composer's direction - also included in this edition), you simply ask. Slava will tell you that Shostakovich was tremendously excited, surprised by (but feeling kinship with) its introspection, moved by the unbowed dignity of the solo part striving to free itself from the Stygian bass- heavy colours of the orchestral writing. He'll also tell you, as an afterthought, that David Oistrakh was "drawn like a magnet to his radio set" during that first performance. Now there's a picture to keep in mind as you listen.

But isn't it fortunate that we can listen? Unlike Richter, who insisted that everything he did was recorded, Rostropovich was generally opposed to the presence of a microphone at live performances (the spectre of big brother?). It was, he says, "like a Berlin wall coming between me and the public". But, as Richter later convinced him, if only one performance in a hundred was to prove really special, then it would be worth it. It was.

The telephone is ringing. Again. This is becoming something of a sideshow, a running gag a la Gogol. The Russian newspaper Izvestia is asking if maestro could confirm or deny that he has signed a letter to Yeltsin about the situation at the Bolshoi. He denies it. Loudly. Later comes a would- be male secretary with a stutter (or so I'm told). From where I sit the young man sounds like he's been left mid-sentence in another barrage of Russian consonants. Slava's telephone manner is at best cursory.

"So, my dear, where were we?" Shostakovich's Second Cello Concerto, the one we so rarely hear. "Ah, yes, genius composition, among the most genius compositions of Shostakovich! Much deeper than the First, this work ... much misunderstood. You know, when I play first performance in London when Shostakovich was awarded the Royal Philharmonic Society Gold Medal, one critic said that after this composition, he should give the medal back! Can you imagine?"

I can. For years, this elusive music deceived the Soviet authorities, so why not a London critic or two? After all, the greatness is in the subtext.

Perhaps Slava, the dedicatee, could throw some light on the mysterious percussion motif (a kind of celestial clockwork) first heard in the renegade Fourth Symphony (withdrawn from performance during the Stalin era) and again in both this concerto and the final pages of the final symphony. A symbolic act of defiance, perhaps, a last laugh echoing all the way into the hereafter? Slava is not so sure. "I think it began in the Fourth Symphony as an effect, but later became like a lucky charm. At the close of the Concerto, earlier material is recalled..." Like Shostakovich's life flashing before him? "Exactly! And so we follow this 'magic trail' of percussion into another life..." Perhaps the nearest he came to a happy release.

"You see, Shostakovich was a realist. Prokofiev was the escapist. They could not have been more different. Prokofiev always preferred to take us away from the reality of life to another fantasy. If he wrote a ballet it was Romeo and Juliet or Cinderella. Shostakovich would write The Bolt!" Prokofiev, says Rostropovich, never really understood what was happening in the Soviet Union. When he was denounced during the Stalinist purges of 1948, he asked the Union of Composers to explain the problem to him: "I have such a great technique as a composer, you tell me which style you like and I will compose in that style!" He liked the recognition, he needed it. "Before 1948 he had collected five Stalin prizes and he wore them like medals," says Rostropovich. "So when the crash came, he was devastated. He imagined that people were pointing at him in the street and saying: 'There goes that bad formalist composer.' Shostakovich always understood perfectly what was happening. And he wrote about it. He wrote about our lives in the Soviet Union, not his own, ours. Prokofiev would search for beauty and joy in his music. Shostakovich would say - here is no joy, only injustice, sadness, tears..."

Two years ago, Rostropovich came across five crumpled sheets of paper among his belongings. On them, in Shostakovich's own hand, were the outlines for 11 concerts, six symphonic and five chamber. He recalls how he had requested the composer's assistance in putting together a festival of his music, and how this had been his response. We're talking here of the dark days of Soviet Russia, so the choices are interesting. Symphonies 1, 5, 13, 12, and 11 - in that order. The inclusion of Nos 11 and 12 at the expense of Nos 8 and 10 (generally regarded as masterpieces and duly included in Rostropovich's London series) is especially revealing - a sign of those times. The 11th commemorates the failed revolution of 1907 and threads revolutionary songs into its musical fabric. The 12th, subtitled "The Year 1917", is the composer's so-called "Lenin" Symphony and much inferior - a bombastic, tub-thumping edifice culminating in a preposterously drawn-out coda. Rostropovich is suddenly in full cry: "Communists forever! - pom-pom-pom - Power to the people - pom-pom-pom - Death to the capitalists - pom-pom-pom. Empty music, like politicians' words. Shostakovich could not lie. He was disillusioned. His heart was not in this piece. When I conduct it, I can hear the compromises he made in the harmony. Not too much dissonance - much consonance. He knew the names and faces of all the Politburo, he knew that if instead of writing a chord of C-E-G, he wrote C-E flat-G, they would frown and say, 'But this is about Lenin! Why this doubtful E flat?!' So the authorities, they love this piece, and you know, he included it to make it easier for me to organise the festival. But you notice he did not end with the 12th, but with the 11th! Now this is genius composition like a Requiem for all revolutions, for all victims. As Goethe said: 'Under our clothes, we are all naked...' " Shostakovich's 11th Symphony ends with tunes of glory dashed by the minor- key clanging of the death-knell. And it tells us a lot about the composer's conscience that he should wish to end a major retrospective of his work with such a sound. A warning. When he conducts the work, Rostropovich lets the bells ring on, "like the voice of God".

Right now he's sounding more and more like the voice of Shostakovich, albeit in some extrovert reincarnation. But the one-to-one, once removed, is over. Taiwan calls. Citizen of the world. Now and forever. On that note, he's instructed his wife that should he die in London or Paris, she's to get his body on Concorde immediately so he can be in New York two hours before he breathes his lastn

The 'Rostropovich 70' series at the Barbican, with the LSO under Rostropovich, Zubin Mehta and Seiji Ozawa, begins Sat, with four further concerts, on Tues, Thurs, 16 and 25 March. All performances 7.30pm. Booking: 0171-638 8891