Das Wunder der Heliane, Royal Festival Hall, London

There are many reasons why we have waited 80 years for even a concert performance of Erich Korngold's operatic steamer, Das Wunder der Heliane. But first among them is the fact that it's unstageable. Putting aside the musical difficulties, the inhuman tessitura of some of the vocal writing, the exhaustive instrumental requirements – all are possible. It's the libretto, by Hans Müller, that's impossible.

In a society in love with death and ruled by fear, can true love bring about a miracle? Will temptations of the flesh lead our protagonists to God? Cue the purple platitudes – three hours of them. "Your body must be like God's tabernacle opened on the night of Creation". Blimey. It's enough to have the fundamentalists picketing the hall.

The point is, though, that Das Wunder der Heliane is too facile, too pretentious, to be offensive. As opera, it succumbs to indulgence over narrative cohesion, and it does so at the same pitch of hysteria for much of its protracted duration. Even so, it's hard to resist the noise that it makes. The young Korngold emerges like the obnoxious love child of Strauss and Puccini, his orchestra iridescent with shimmering keyboards – key-glockenspiel, celeste, piano and eerie harmonium lending that other-worldly patina. When his heroine sings "My body exults", so does the orchestra, strings and horns in unholy alliance. The effect is often indecently gorgeous, the prelude to Act III, for instance, a thing of almost transcendent beauty.

Vladimir Jurowski and the London Philharmonic kept their powder dry in what was largely an exemplary, often exciting account of this overwrought score. But the impression of undercasting was compounded by the shocking vocal state of Andreas Schmidt as the Ruler – a once beguiling voice clearly ravaged by unwise choices. Had no one heard him recently?

At the opposite extreme was a young and immensely promising heldentenor in Michael Hendrick. He rode the often inhuman tessitura of the Stranger with courage and belief, singing and phrasing with real beauty, not just brawn.

Patricia Racette certainly found and delivered the money notes for Heliane – but she was oddly disappointing in her big set-piece aria in Act II, woefully short in pitch of the required ecstasy. And as she and her Stranger were locked in the eternal embrace of death, you couldn't but wonder if it might be another 80 years before we hear from them again.