Flushed with critical success among the theatrical community, the National Theatre has now invited the music critics to give Michael Longhurst’s new production of Peter Shaffer’s Amadeus the once-over. And since the press is currently in a lather over the latest “young Mozart” sensation – a precocious 11-year-old who simply can’t stop writing operas – it seemed a good moment to check out this classic treatment of the real one. First performed in 1979, Shaffer’s play became a film of the same name in 1984 – the writer died in June, aged 90. Amadeus may be essentially a fiction, but it’s an intriguing essay on jealousy and genius, and it’s worn surprisingly well over the years.

Longhurst’s remarkable achievement is to have turned a straight stage play into an epic piece of music theatre. It obviously helps that his designer, Chloe Lamford, has a background in opera, but I have seldom seen as confident a melding of speech and song, music and image. Equal partner with the NT actors is the Southbank Sinfonia, a hugely talented young ensemble whose performances are always theatrical.

Lucian Msamati is heroically commanding as Salieri and, with excerpts from Mozart’s oeuvre interlarded with unobtrusive stretches of contemporary mood music, the whole thing coheres astonishingly well.

Shaffer’s conception of Mozart is exceptionally tricky to bring off, but Adam Gillen does this with haunting conviction, while Karla Crome (Constanze), Tom Edden (the Emperor), Hugh Sacks (Rosenberg), and Geoffrey Beevers (Van Swieten) lead a superb cast through this kaleidoscopically changing landscape of sunlight, shadows, and magnificent sound. I and my companion left with the Requiem ringing in our ears and, accompanied by visions of its newly reincarnated creator, it rang for much of the night.