A', not ‘The'. This isn't Die Zauberflöte as written by Mozart but a 95-minute potted version adapted by the formidable Peter Brook, now 86, and conceived as his farewell production to his Paris theatre, Les Bouffes du nord.

To say that expectations for this ran high is an understatement. Armed with vivid memories of Brook's chamber version of Bizet, La Tragédie de Carmen, and having made multiple pilgrimages to his peerless Don Giovanni at the Aix Festival some years back, I had put a big red circle around this date months ago. What sadness, then, to witness such a dispiriting swansong from a great director.

Brook's late work for the stage has become increasingly stripped back (though always stylishly so) to encourage audiences to focus on the drama. With A Magic Flute he catastrophically extends this dépouillement to the musical performance, and in his quest to present the essence of Schikaneder's story he treats Mozart's score with something approaching contempt. The orchestra gives way to a faceless piano reduction (played either by Franck Krawczyk or, as on Friday, by Matan Porat), the vocal calibre of his young cast is frankly third rate (again, there are two casts who alternate throughout the run; the second may possibly be stronger), and those arias that survive the cut-and-paste are thrown off like unwelcome intrusions upon lethargy.

Brook's love of the exotic prompts him towards a visual language of bamboo sticks and vaguely Arabic costumes. Although such stylistic decisions have no bearing on the story, they do not detract from it either and present good surfaces for receiving Philippe Vialatte's subtle lighting. That, unfortunately, is as good as it gets.

The performances of the players are so muted that one wonders what can possibly have occurred during Brook's extended rehearsal period. Only William Nadylam displays any charisma at all, and his task is not to sing but to narrate the missing plotlines – which begs the question: why make cuts to essential material in the first place? And why then interpolate an aria from elsewhere (for Papagena) that contributes nothing either to the action or to the dramatic structure?

The sensation of lèse majesté in criticising such a legendary figure as Peter Brook is as nothing compared to Brook's own hubris in presuming to improve on Mozart. Whereas thirty-odd years ago his Carmen was a masterpiece of concision; this Flute is a massacre by excision. As for the staging, it's hard to believe the great director has seen any of the good work being done by other creative hands in the 21st century. His ‘bare essentials' shtick has developed little in recent times and it's beginning to look very tired now. This is deadly theatre.