CAMUS wrote Caligula at the end of the Decade of the Dictators, and saw its first performance in 1945, when Paris audiences were maybe too ready to identify the barmiest of Roman rulers with the imperial megalomaniacs who had just perished.

Yes, the play is very obviously about the misuses of power. But, for better or worse, it’s also a study of nihilism in action.

Be prepared for some pretty ravelled philosophy. But also ready yourself for a riveting performance from Michael Sheen. Everything about this actor — pale face, chaotic hair, knife-like nose, weird unsettling grin and general demeanor of a Dorian Gray half-way to becoming his picture — suits Camus’s anti-hero.

Maybe Sheen misses a sort of twisted pathos, for Caligula is and knows he is also the victim of his own excesses; but he catches the mix of gleeful mockery and self-hatred that’s surely wanted.

Michael Grandage’s production, which occurs on a bare stage backed by a vast gilded wall, doesn’t neglect tension and narrative pace in its attempt to do justice to Camus’s ideas.

We see complacent, self-serving senators reassuring each other that they can control and manipulate a promising young emperor, only to find him killing their children and parents, whoring their wives, cramming poison through their lips, and, almost worse, making them worship him as a reincarnation of Venus in gold skirt and bra.

What is perhaps offputting — for earthbound English audiences as well as the only patrician who exudes integrity and reason, Raymond Coulthard’s Cherea — is that Caligula has been reborn as a certain sort of French logician.

Having lost the sister who was also his mistress, he concludes that “we die and are unhappy”.

Therefore the world is meaningless. Therefore he’ll mimic the cruel gods he anyway believes don’t exist. Therefore he will bring famines and plagues, along with all-consuming terror and arbitrary killings, to people whose failure to stand up to him excites only his contempt.

I don’t think that Suetonius, who chronicled Caligula’s cruelties, would recognise this disillusioned idealist, especially when he starts blathering on about his search for “the impossible” and saying things like (to a poet who provokes his scorn by suggesting there’s order and meaning in the world) “You are pure goodness and I am pure evil”, or “The past and the future gatecrash my head and never go home.”

Frankly, I too flinch at lines that sometimes come across as high-grade metaphysical melodrama.

But when Sheen’s Caligula is sweetly smiling as he prepares to take literally the senator who has just said he’d happily die for his sake, or shrieking in self-disgust at his own image, or bunched and preparing for violent death, the energy-level at the Donmar is unmissably high. A bold choice of play, finely staged.

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