Pirandello’s original begins with the sextet of the title invading a rehearsal of the same dramatist’s Rules of the Game and demanding that the producer and his actors work on the family tragedy their own author left unfinished. Rupert Goold’s reworking and updating is radically different. This time the characters interrupt the shooting of a “documentary drama” that involves a boy who has come to die in a suicide unit in Denmark — but which is criticised by a visiting television executive for lacking excitement and edge.

So the sort of TV programme which leaves you unsure of what’s fact and what’s fiction has become one of Goold’s subjects and targets. That’s surely in the spirit of a play which, among other things, attacks old-style theatre for its falsities.

The result is a production I found as exhilarating as Goold’s award-winning Macbeth seemed tricksy. The play the six characters proceed to perform, and these TV actors try and fail to replicate, comes painfully, horribly to life. The scene in the ad hoc bordello run by Pace — here, a sleazy pimp in a flowery shirt, not the grotesque madame of the original — is as ugly as a 21st-century Pirandello might make it. Ian McDiarmid’s Father comes at Denise Gough, playing the underage girl he doesn’t yet know is his stepdaughter, not just with slimy words, but with rouge, scissors, a little-girl dress and sick fantasies galore.

McDiarmid’s dry, sardonic self-contempt combines with the equally excellent Gough’s disgust and fury to save this play-within-a-play from mere melodrama. Moreover, Pirandello’s serious points come across less wordily and preachily than usual. If life can’t match the concentrated intensity of drama and the other arts, art can’t capture the complexities of life, which is always in flux and whose truths are anyway likely to be disputed by people with as many biases, agendas and reasons for self-justification as these six characters.

There’s a stunning moment in which dialogue escalates into music and the agony of Eleanor David, playing the stepdaughter’s mum, becomes literally operatic. That, too, says something about the strengths and limitations of art, but there’s also an ending that would disorient even Pirandello’s brainbox. Let’s just say that the Sicilian author is seen moping at his desk while McDiarmid murders BBC worthies who are reducing Six Characters into a docudrama and Noma Dumezweni, playing the original producer, cradles a dead boy. Too complex? Maybe; but exciting all the same.

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