Although the 51-year-old Gergiev doesn't take up the post of LSO principal conductor until January 2007, audiences will get a chance to experience the "special relationship" he says he has with the orchestra when he conducts a Shostakovich symphony cycle at the Barbican starting in October. But it's significant that the LSO has to share the celebration of Shostakovich's centenary with three other orchestras - Gergiev's Mariinsky Theatre Orchestra, the Rotterdam Philharmonic, of which he is also principal conductor, and the Vienna Philharmonic.
Gergiev is clearly delighted to be chosen by the LSO, but his real passion is reserved for the Kirov Opera and Ballet, based in the Mariinsky Theatre. "You can say many things about Valery Gergiev," he once told the critic Norman Lebrecht, "but I never put Mariinsky second. You either commit yourself, or you don't."
With a single-mindedness that borders on obsession, Gergiev has thrown himself into creating a company to rival, and many would say, overtake, the Bolshoi in Moscow. London audiences will see the results at Covent Garden this summer, wherea two-week ballet season is followed by lavish productions of two major Russian operas and Puccini's Turandot, conducted by Gergiev himself.
Only Gergiev would think of conducting seven opera performances in six days. But when we meet before a concert with the Israel Philharmonic, he waves away suggestions that he might share the load. "It's not so difficult if the repertoire is Mussorgsky's Boris Godunov and Khovanshchina. They are cultural icons which are looked at with huge admiration in my country. Quite simply, they should be conducted by the man in charge."
In this age of minimalist, producer-led opera, the Kirov productions for Covent Garden have a distinctly Cecil B De Mille style. They're a riot of spectacular tableaux, sumptuous costumes and a cast of hundreds. And that's just a small fraction of the Mariinsky company. "Our forces are huge, about 2000 people," says Gergiev proudly. "It's big. And we have to make sure that artistic qualities are high, too. Every opera house faces the risk of producing uneven quality. But we bring Boris Godunov and Khovanshchina the way they look and sound in St Petersburg, and we hope you enjoy it."
There's a note of challenge in his voice, and I wonder if he's recalling the drubbing he received from British critics in 2001 when the Kirov departed from its Russian repertoire to bring a Verdi season that was accused of being under-rehearsed and undistinguished. "I'm a bit too old to be worried about critics! I could share with many conductors the good reviews I've had, and there would still be plenty left!"
You don't pick fights with a man who's negotiated the shark-infested waters of post-Soviet Russia and emerged with President Putin as a personal friend. Swarthy, rumpled, with a habitual scowl, Gergiev is not an engaging figure - until he starts talking about his pet projects. Then the scowl vanishes, a smile plays at the corner of his mouth and you glimpse the indulgent father rather than the ruthless autocrat. Though he doesn't talk about his family, he has three children with his young wife, a music student from his home town of Vladikavkaz in Ossetia, who was said to have been introduced to Gergiev by his mother.
Gergiev has deployed the charming side of his personality on the rich and powerful to gather financial and political support for the Mariinsky. I've seen him at PR luncheons working the tables and handing over his number to anyone who might be enlisted to the cause. And it has paid off - the Mariinsky can now afford to run a training orchestra and an Academy of Young Singers, run by Gergiev's sister Larissa Gergieva, both of which feed the main company.
Our conversation keeps returning to the White Nights Festival, when the music world converges on St Petersburg for a six-week season of ballet, opera and concerts, centring, naturally, on the Kirov company and their star soloists. "It's big, well-known, and it sells in millions of dollars," he says bluntly. He wants it to be even bigger. Expansion plans include the renovation of the 19th-century theatre and the construction of a new theatre, Mariinsky II, plus a new concert hall with state-of-the art acoustics.
Gergiev justifies this empire-building by saying the Kirov staff is bursting out of its cramped and unsuitable quarters. "Our forces deserve to be given even more chances, and bigger and more comfortable facilities to polish their talents." In another 10 years he reckons the area around the Mariinsky and the island of New Holland, first built on by Peter the Great, will be buzzing with open-air concerts, smart eateries and art galleries. "It will become a new centre of gravity in St Petersburg, and provide tourist attractions to rival those of Moscow."
But Gergiev is well aware that the Kirov must continue to keep its profile high outside Russia. "We belong to an old-fashioned traditional group of cultural institutions which doesn't function like it did maybe 100 years ago, when Toscanini and La Scala would travel by boat to perform in South America. We should never stop bringing our traditions to audiences around the world, and exchanging our cultural riches. This is happening in London with our regular residencies at Covent Garden. And we actually invited the Royal Ballet to St Petersburg some years ago. God knows how much it cost - in my 17 years we never lost that much money! But we thought it was important."
Gergiev insists there will be no watering-down of the Russianness of the productions this summer. "We will do Boris Godunov and Khovanshchina in a way that fully respects the traditions handed down from our predecessors. And when we perform Turandot, we do it with Russian voices - Irina Gordei as Turandot, Vladimir Galuzine as Calaf. We love this opera, but of course people will say, why Turandot? You can't force people to bow and say, 'Yes sir, we're going to love it', even before they hear it." He needn't worry - the Kirov residency in London will sell out whatever the repertoire.
"Three minutes, Mr Gergiev." The general manager of the Israel Philharmonic hammers on the door before I've had time to ask about Gergiev's fundraising activities for the children of Beslan, a tragedy that took place not far from his home town in Ossetia. While he throws on yesterday's concert shirt, he reminds me that he's conducting the World Orchestra for Peace at the Proms in August, and has just started saying how he's looking forward to coming to Covent Garden in July when the manager drags me away.
Just 10 minutes late, Gergiev bounds on stage to conduct L'après-midi d'un faune with absolute commitment. It's 2pm on a Friday afternoon, but the performance is mesmerising. Surely the LSO won't regret its decision.
The Kirov Ballet and Opera companies, directed by Valery Gergiev, are at the Royal Opera House, London WC2 (020-7304 4000) from 18 July to 6 AugustReuse content