But regardless of its sheer physical size, what about the Bolshoi's tradition of greatness? In the recent economic and political upheavals in Russia, the theatre has not escaped sharp poundings which have resulted in its once glorified reputation becoming somewhat tarnished. News filtering out of Moscow after glasnost depicted a theatre with huge financial challenges, stagnant repertoires and backstage bickering - especially in the ballet company, whose overseas tours began to lack lustre and appeal, a fact well documented in a Channel 4 film, Dancing for Dollars, about the troupe's disastrous visit to Las Vegas three years ago.
Yet, convinced of its immortality, and buoyed by the indomitable Russian spirit of optimism, the theatre has managed to remain afloat. More recently, with changes in management, there have been positive glimmers of hope that the Bolshoi is undergoing rebirth and regaining its former glory.
Ballet performances in Moscow over the past year have shown a healthier company with diversely talented stars and an excellent, well-drilled corps de ballet. Vasiliev feels the time has come to draw back the curtains (which, in the company's Moscow home, are still embroidered with the hammer-and sickle) and show what has been accomplished in his four years at the helm. "I did not want to send out the companies before," he says in his plush office at the famous theatre. "So I have waited until now, when we are ready for a big tour with new repertory and a new level of quality. I want to show British audiences the whole Bolshoi - the opera, orchestra and ballet - to show the Bolshoi Theatre in full force."
After the 1917 Revolution, the Bolshoi Theatre stood for the biggest and best in Soviet culture. A hotline to the Kremlin assured that its coffers were constantly filled to nourish and promote the opulent productions which also acted as propaganda tools for the country's communist image. Every visiting dignitary was automatically taken to a night out at the plush red and gilt theatre to be awed by Soviet artistic and cultural supremacy. The opera company staged lavishly designed and sumptuously costumed creations which overflowed with de Mille-style casts-of-thousands, while the ballet's athletic, full-blooded dancers catapulted over the wooden, raked stage in waves of undulating heroism.
Initial tours abroad took the West by storm, while at home the performers were cult figures, known by all, from the Politburo autocrat to the collective farmer. To be a member of the Bolshoi Theatre meant fame, status and a very good living. But the advent of glasnost, perestroika and the second Russian Revolution, changed the fairy tale into real-life drama and the theatre fell on hard times. This was especially evident within the ballet company, where the dancers were divided in their loyalty to their brilliant but autocratic director of 30 years, Yuri Grigorovich; on his controversial departure, some members staged a strike.
Vasiliev's appointment as general director of the theatre surprised many as it was automatically assumed that he would be first in line to take over from Grigorovich at the ballet company. His life and career has been centred around the ballet. A pupil of its choreographic school, he joined the company at 18 and quickly became one of its legends, performing Russian classics with grace and elegance, and new Soviet works with muscular power and bravura. He first met his future wife, the exquisite ballerina Ekaterina Maximova, in the classroom when they were both 10, and the two became the darlings of Moscow. Banished from the company by Grigorovich in the 1980s for speaking out about the loss of the Bolshoi's Russian classical heritage in the director's choice of repertoire, both dancers gained valuable experience at home and abroad.
"I didn't seek this position," Vasiliev says about his new job, "but I was told that if I loved my theatre I should take it." He has worked hard in the past four years to pull up the standards of the companies and restore confidence. "All the artists now have contracts," he reports proudly, "and I think you'll agree that the dancing is better, especially the men, who are now more lyrical, while the women have become stronger."
But this new job has not been without troubles, especially financial ones. At the end of his first season, he warns: "We are living from hand to mouth and we may not be able to open next season for lack of funds. We need $45m [pounds 28m] to survive but only receive $12m [pounds 7.5m] from the government." He sighs as he runs his fingers through his once blond mane in despair.
As well as the running costs of the theatre, an estimated pounds 125m is needed for repairs to the crumbling theatre, though, as one of Unesco's heritage sites, financial aid is expected. And there is still a final payment of pounds 63m to be found for the construction of the Filial Theatre next door. The two companies will move to the new building during the renovation of their old home.
Vasiliev has also been attacked in the press for lacklustre and unimaginative choice of repertoire, to which he answers: "In order to move ahead, we need to remember the legacy of the past. Future generations will never forgive us for the removal of past works." Yet he himself has reworked two of those "past works", Giselle and Swan Lake which will both be seen in London. In the former, the changes are minor, (though the humble peasant girl is now costumed by Givenchy), but in that icon of balletic tradition, Swan Lake, Vasiliev has dared to fiddle with the scenario, replacing the Evil Magician with a step-father King, and the Black Swan with a Russian Princess. His reasoning for these changes is strong, but he will face tough critics in London.
The artistic director of the Bolshoi Ballet today is Alexei Fadeyechev, who ended his auspicious dancing career last summer at the age of 38. Unlike Grigorovich, he believes in accessibility, in an "open-door" policy where any one of his 210 dancers can come and talk things out. But whatever budget cuts are needed, he says he will never consider a smaller troupe: "We need a large company, to fill the stage with white swans and bayaderes if we are to keep the classics alive. And we need to retain the permanent bond of traditional handing down from older ex-dancers to young ones, as in our past."
There will be some familiar balletic faces, such as Nina Ananiashvili, Nadezhda Gracheva, Andrei Uvarov and Mark Peretokin on the Coliseum stage this July, while the Bolshoi's latest stars Konstantin Ivanov, Nikolai Tsiskaridze and the 18-year-old Svetlana Lunkina will be making their London debuts, showing that the Bolshoi spirit and spectacle are not diminished, but very much alive.
Since this is the opera's first visit to London, direct comparisons with past achievements are difficult, though the ballet company will be measured against the Kirov Ballet which brought a scintillating array of productions and dancers to London last year. But the two Russian companies, though bonded by the same legacy, have grown their own identities. They can be compared to that national delicacy, caviar. The Kirov is the black, refined and easy on the palate, while the Bolshoi, a rosy red, is more pungent to the taste and crunchy to the bite. It is also bigger.
The Bolshoi Ballet and Opera are at the Coliseum, St Martin's Lane, London WC1 from 6 July until 7 August. For information and booking 0171- 632 8300