Comparisons, even on paper, between two season openers from London orchestras could hardly have been more instructive. I didn’t attend Valery Gergiev’s London Symphony Orchestra concert last week, for reasons several times outlined on theartsdesk. But quite apart from the fact that Gergiev and his court pianist Denis Matsuev are active supporters of Putin's “Might is Right” campaign in the Ukraine – a situation which tens of thousands of Muscovites are beginning to challenge – Matsuev is also the worst of barnstormers.

It is easy to be blinded by the sensational history of Shostakovich’s ^Seventh Symphony, the “Leningrad”. We cannot forget the famous performance by a starving makeshift orchestra in August 1942, at the height of the siege of Leningrad, or the dramatic way in which the Soviet authorities spirited the microfilmed score out of Russia to America via Tehran. Inscribed by the composer “To the City of Leningrad”, the symphony has been laden since birth with political meaning, much of it contradictory.

This was the most eagerly anticipated programme of the Mariinsky visit - something old, something borrowed and something new. The old, that colourful fairytale of Stravinsky’s lush, melodious youth, The Firebird; the new, a recent acquisition by the Londoners’ favourite Russian, Alexei Ratmansky; and the borrowed, something from English ballet legend, Frederick Ashton’s Marguerite and Armand, once kept under glass with the Fonteyn and Nureyev myths, but eventually released from the museum by Sylvie Guillem and Nicolas Le Riche a decade ago.

The symphony – that structural pillar of classical music – found itself under siege last night at the Proms. Both Berio’s Sinfonia and Shostakovich’s Fourth Symphony assault and subvert, reshape and reimagine the genre, puncturing the Victorian smugness of the Royal Albert Hall with doubt.

Under what circumstances can Shostakovich’s Eighth String Quartet, the most (over)played of the 15, sound both as harrowing as it possibly can be and absolutely fresh? Well, the context helps: hearing it at the breaking heart of the fourth concert in the Jerusalem Quartet’s Shostakovich cycle gave it extra resonance with the works on either side of it. But above all this is a team that plays with a degree of nuance, weight, beauty and commitment that I’ve never heard even the composer’s preferred foursome, the Borodin Quartet, surpass either live or in their numerous recordings.

Depth, height, breadth, a sense of the new and strange in three brilliantly-programmed works spanning just over a century: all these and a clarity in impassioned execution told us why the BBC Symphony Orchestra was inspired in choosing Finn Sakari Oramo as its principal conductor.

Valery Gergiev once described Yevgeny Svetlanov’s USSR - later Russian - State Symphony Orchestra to me as “an orchestra with a voice”. Then Svetlanov died and the voice cracked. Which are the other big Russian personalities now? Gergiev’s own Mariinsky? I don’t hear it. Yuri Temirkanov can still bend the St Petersburg Philharmonic Orchestra to his own whim of iron. The Russian National Orchestra was never in the running. But the Tchaikovsky Symphony Orchestra of Moscow Radio, to give its full title, still sounds as deep and rich as it did when I last heard it live nearly 30 years ago.

Well! Just when you think you’ve constructed a nice tripartite schema for dance styles based on their relationship with the ground, along comes a company which tears up that rule book entirely.