Zurich have treated London to some rather lovely Wagner of late but are not – on the basis of the one and a half exasperating Acts of Radamisto that I could stomach – quite so proficient in Handel. Did you know that the slow movement represents Mozart’s desire to return to the nursery? Me neither! Setting aside presenter Charles Hazlewood’s imaginative psychoanalysis of the score and the toothless colloquy of interviews-to-camera with Nannerl, Constanze and Leopold Mozart – a retrograde step after the wonderful Eroica – both programmes offered one extremely exciting thing: the best period instruments performance of Mozart by a British orchestra, period. The Mozart Collective (aka Harmonieband, depending on which part of the BBC website you visit) was formed ad hoc for the series and is not, as yet, a full-time operation. When or if it is, Britain can finally offer some serious competition to the Orchestra of the 18th-century in this repertoire.Relative youngster William Christie, whose 60th birthday it is this year, flew into town this week for a semi-staged performance of Radamisto Not, alas, with Les Arts Florissants but with Zurich Opera. Too rich for Mozart perhaps, but of perfect scope and subtlety for Bruckner’s final, unfinished symphony.This is a paradoxical work.

Reflection, doubt, tenderness and acquiescence – the final movement’s extended “Dresden Amen” – frame an implacable, mechanistic scherzo that, more than any of Mahler’s neurotic symphonic prophecies, heralds the industrial-scale carnage of the First World War. In Rattle’s hands in September 2002 at the Royal Festival Hall, the scherzo was an Expressionist hail-storm of splintered bones. A judgement-day nightmare that decimated the high-vaulted ecclesiastical structure of the first movement. In Haitink’s it was organic, private, taut, slow, restrained, regretful, guilty: a cruelly curdled distortion within a clean Romantic super-structure and quite the most terrifying thing I’ve heard in a concert hall. If Mahler’s Ninth (with the Vienna Philharmonic), Sixth (with the LSO), and Third (with Berlin) Symphonies are as compelling as this, Haitink’s 75th year may well be his finest.As Haitink’s Mozart with Andras Schiff seemed stiff in contrast, it was interesting to catch the same concerto (K466) played so vivaciously by fortepianist Ronald Brautigam on BBC 2 and BBC 4’s The Genius of Mozart and Mozart Uncovered.

(Like the Berliner Philharmoniker, whose contribution to “Haitink at 75″ takes place in September, the Concertgebouw is now a young orchestra.) But the technique, sensibility and sound remain exceptional: smooth, refined, vibrant and deliberate. A finer palette for an an old master like Haitink is hard to imagine. These are the years when certain performances achieve an impact that you hope never to forget: Davis’s Peter Grimes and Les Troyens, Mackerras’s Brahms 1, Abbado’s Parsifal and, now, Haitink’s Bruckner 9.
Last weekend, nearly 50 years after his professional debut, Bernard Haitink began his 75th birthday concert series at the Barbican with the Royal Concertgebouw Orchestra: the orchestra he grew up listening to, the orchestra of which he was Principal Conductor for 24 years, the orchestra of which he is now Honorary Conductor – a role created to acknowledge their life-long connection The faces of the players may have changed. For conductors lucky enough to make it to their 70s in good health, it is a precious decade. This is the decade when a lifetime’s influences and ideas coalesce, when new thoughts and techniques make their last brilliant entrance, when knowledge supersedes showmanship and the world’s greatest orchestras move to their maestro’s side like mountains to Mohammed. For an audience giddy with the Indian summers of several outstanding septuagenarians, these are precious years too.