The brutality of dementia is at the heart of this dark but gently humorous play that both unsettles and embraces the audience.

Translated by Christopher Hampton from Florian Zeller’s French original, the film version of The Father won the writers an Oscar, alongside one for screen lead Antony Hopkins.

At Norwich’s Sewell Barn, John Dane puts in a similarly stellar performance as André, the titular father who is losing his grip on the world around him. Dane’s performance thoughout is virile, energetic and engaging – full of confidence, all aimed at disguising his increasingly shaky footing.

He is cruel – unforgivably so at times – but his warmth remains unnervingly seductive, almost literally so in one surprising scene.

Hampton and Zeller’s script knocks the audience off kilter too, leaving us wondering where the truth lies, what is real and what is imagined, and who can be trusted.

Daughter Anne is played by Jenny Belsey, with a largely blank palette – a woman drained by circumstances, with only the energy for just the odd flicker of emotion at the edges of her face.

Neil Auker, Jo Parker Sessions, Lauren Baston, and Trevor Burton support in a criss-cross of roles, also serving as stage hands and conspiring in the gradual bleaching of Chris Bealey and Phil Williamson’s set from comfortable Paris flat to the cold clinical necessity of a ‘care’ home.

Bealey’s direction does a good job of pitching the piece, balancing André’s weaponised sarcasm with the pathos of his situation and keeping the audience on their toes for the full one hour 45 straight-through run.

This is not an easy watch, but a very rewarding one.