The diva, the director and a fight at the Russian opera

Russia's world-famous Bolshoi Theatre is at war. It is a battle that has pitted the traditionalists against the modernists and left the illustrious theatre scrabbling to defend its hard-won artistic reputation.

And it is a conflict that has triggered dark mutterings about a plot to blacken its famous name engineered, it is claimed, by "the other place" - the Mariinsky (formerly the Kirov) Ballet in St Petersburg.

The first shot in what has become a damagingly public debate about the Bolshoi's future was fired by Galina Vishnevskaya, its most famous diva and wife of the renowned conductor and cellist Mstislav Rostropovich. Ms Vishnevskaya was due to celebrate her 80th birthday at the Bolshoi on 25 October, more than 50 years after she first trod its boards as Tatyana in Tchaikovsky's Eugene Onegin. But what was supposed to be a celebration among Russia's cultural elite turned dramatically sour.

Ms Vishnevskaya alleged that the Bolshoi's growing appetite for modernist "experimental" interpretations of some of Russia's most hallowed masterpieces had got out of hand, and said she would take her party elsewhere. She reserved particular scorn for a new version of Eugene Onegin, the first modern interpretation of the classical opera in more than 60 years.

Ms Vishnevskaya claimed that the opera had been ruined by the modernist director Dmitry Chernyakov, who once set Tristan and Isolde on a submarine. The soprano penned a public letter to the Bolshoi's shell-shocked management, telling them the new production had driven her to "despair and humiliation" and a "national treasure" had been maligned.

"It's appalling," she said in one interview. "How can a masterpiece of opera be treated in this way? I suddenly understood that I don't have any relation to this theatre any more." She added: "I will not rid myself of the shame I felt for being present at such a public desecration of one of our national treasures until the end of my days." So great was her fury that she vowed never to set foot in the Bolshoi again.

The opera, based on a 19th-century novel in verse by Alexander Pushkin, Russia's equivalent to Shakespeare, is regarded as sacred by Russia's cultural guardians. It tells the story of a nobleman, Onegin, who kills his friend, Lensky, in a duel sparked by jealous love. It is a tragic tale of unfulfilled love, missed opportunities, and crossed wires.

To Ms Vishnevskaya's horror, the new version portrayed some central characters as alcoholics or mentally unstable, and had Lensky killed by accident rather than in a duel.

The Bolshoi could not shrug off her criticism easily; she is "a people's artist of the USSR", one half of the global cultural community's most famous couple, and a friend of the reclusive writer Alexander Solzhenitsyn and the late classical composer Dmitri Shostakovich. What she called "the deformation" of Eugene Onegin was particularly painful for her at a time when she was preparing to celebrate her life's work.

Ms Vishnevskaya's first role at the Bolshoi in 1953 was as Tatyana in Eugene Onegin, and her last stage appearance in Paris in 1982 also saw her play the part of the provincial beauty whom Onegin spurns only to woo unsuccessfully later.

The Bolshoi's general director, Alexander Iksanov, has argued that the famous theatre needs to innovate to stay fresh. "The need to have new interpretations of classical works is an imperative of our time. It is a pity that talented people do not understand that," he said.