The Helikon is a Moscow opera theatre, an elegant, pastel-green mansion dating back to the 18th century in the very heart of the city. As might be expected of an opera house, it exudes dignity and grandeur – or at least it did until it was covered up in green tarpaulin, and major renovation work started. It is these renovations that have made the theatre the centre of a bitter battle that has divided the Russian capital's artistic community and led the two sides to accuse each other of being vandals and extremists.
After a changing of the guard in Moscow's political scene, the row over the reconstruction has suddenly become a political and cultural test for the city's aesthetes – as well as for its new mayor, who faces a decision that will shape his cultural agenda barely three months into the job.
On one side of the battle lines is the Helikon, a young dynamic opera company that is regarded as one of the best in Russia. On the other side is Arkhnadzor, a group of architectural preservationists who have often been seen as the lone voices of protest as some of Moscow's heritage has been destroyed in recent years.
The Helikon company had planned for years to renovate its theatre complex, adding a big stage to the tiny 200-seat theatre it had previously used. Work finally got underway on the project two years ago, but in September, the Kremlin fired Yuri Luzhkov, Moscow's controversial mayor of 18 years. Almost immediately, the interim government suspended the work along with other Luzhkov-era projects, saying it needed time to decide on the objections.
Now Moscow's cognoscenti are waiting with bated breath to discover how new incumbent Sergey Sobyanin will react to issues of culture and architectural preservation. But so far, there has not been a word on the issue from him.
The preservationists have called the opera company "vandals" and say that if the Helikon is allowed to continue the work, it will be a green light for other controversial projects across the city. The Helikon accuses them of pursuing a vendetta against the theatre, claiming that they do not kick up such a fuss over dozens of other commercially-oriented projects that are far worse and that the reconstruction work does not technically break any laws.
It has been a depressing and unedifying spectacle for those who value both Moscow's rich operatic culture, and its disappearing architectural heritage. The theatre's plans do indeed involve major changes to the building – the previous inner courtyard will be given a roof and become the main stage, with the former exterior walls becoming interior walls, and other structural changes are also planned.
But at the same time – unlike dozens of other new buildings that sprouted up in Moscow during the reign of Mr Luzhkov – the plans are architecturally impressive, and the debacle has left Muscovites wondering if Arkhnadzor might have picked the wrong target.
A radio debate over the weekend between Dmitry Bertman, the Helikon's artistic director, and Rustam Rakhmatullin, one of the co-ordinators of Arkhnadzor, quickly became an angry shouting match. Both sides claim that the other is manipulating media coverage against them, and Mr Bertman says he has received threatening anonymous phonecalls. In recent days, he says, all the money was emptied from one of his bank accounts . He does not know if it is linked to the reconstruction scandal, but doesn't rule it out. Over the weekend, the Helikon was staging its production of Dmitry Shostakovich's opera Lady Macbeth of Mtsensk, first put on a decade ago. The opera, one of the most significant works of the20th century, was banned in the Soviet Union when Joseph Stalin went to see it in 1936 and stormed out at the interval.
The Helikon's production was the first revival of the opera in its original form in Russia, a mark of how significant the theatre is to the city's cultural life. At each performance, the audience were asked to sign a petition to the mayor, calling on him to restart the work and ignore the "extremist journalists" who oppose it.
An emotional open letter to Mr Sobyanin has also been written by six of Russia's biggest opera stars on the world stage, including Anna Netrebko and Dmitry Khvorostovsky. "All of us have travelled the world and performed on the most famous opera stages, from Covent Garden to the Metropolitan... and we can proudly say that the Helikon is not just the pride of Moscow but the calling card of Russia abroad," wrote the stars.
"In Moscow there are no ancient Egyptian temples or Roman coliseums," they said. "But we have a theatre the like of which they don't have in either Egypt or Rome". Cities grow and develop and it is never possible to avoid completely a few architectural "victims".
The preservation movement has responded with their own, equally passionate letters to newspapers and to Mr Sobyanin, calling the reconstruction of "vandalism" and insisting that the reconstruction work be abandoned.
"This is exactly the same as many other projects that were begun under the former mayor, but with this one we still have time to stop it," says Mr Rakhmatullin. "I don't think there should be any special dispensation just because it's a cultural project and not a commercial one. Everyone should be equal before the law.
"If this is allowed to go ahead, there will be hundreds more so-called 'reconstruction' projects, and the old Moscow will continue to disappear before our eyes," he added.
Mr Bertman is equally adamant: "It's very simple – if we can't continue with this project the theatre will be dead; Moscow will lose a theatre."
It will be up to Mr Sobyanin to decide which of the sides has the stronger argument. A city's cultural elite is hanging on his decision.
One of the most poignant symbols of the destruction wreaked on Moscow under Yuri Luzhkov, the vast Hotel Moskva, which stands just at the entrance to Red Square, was knocked down in 2004 and rebuilt again to the same design but with cheap and tacky materials.
Detsky Mir department store
Moscow's biggest toy shop, Detsky Mir was ironically located just across the square from the Lubyanka, the headquarters of the KGB. Now closed for renovations, preservationists have warned that the building could be ruined.
Moscow's most famous theatre was closed down in 2005. The building was structurally unstable and needed a complete overhaul. The building work has been repeatedly delayed and the current estimate is that the theatre will not reopen before October 2011.
Another musical institution that was so in need of repair it was almost falling down. Arkhnadzor are opposing the reconstruction work, claiming that additional structures are being built that will ruin the building's historical features.