King Lear, Courtyard, Stratford-upon-Avon

You don't have to be old to play King Lear but it helps. The late, great Eric Porter first played it when he was 26. Greg Hicks is no spring chicken, but he's no ancient of days, either. This extraordinary actor, who seems exclusively devoted to the heroic stage, simply plays a barbaric monarch who has defied old age by embracing his own tragic fate.

David Farr's apocalyptic production of Shakespeare's greatest play is a rousing starter to the RSC's final season in the Courtyard before their new theatre re-opens across the road at the end of the year. It throbs with a sense of the world turned upside down. Gloucester is putting it mildly when he says, "These late eclipses of the sun and moon portend no good to us."

It's not so much a question of biding the pitiless storm on the heath as of taking up arms against a sea of woes and entering a battle of the elements to the bitter end. Hicks's preparation for becoming that foolish fond old man is to savour this challenge with an almost demonic stupidity and fervour.

Nothing will come of nothing when Cordelia fails to heave her heart into her mouth, but Hicks's Lear is less interested in filial pieties than in spoiling for a fight. Never was a Lear less convincing in his plea not to be mad. He's gagging for it, and Kathryn Hunter's Fool – a sly, wry, wizened jackanapes – observes his disintegration with a strange kind of mocking approval. It's as though the Fool has been there before.

Straggle-haired and great-coated, Hicks takes to the hermit life with the wilful, alternative majesty of Ben Gunn in Treasure Island and his assumption of the floral coronet as he cradles Geoffrey Freshwater's blind Gloucester, always the most unbearably moving of scenes, marks his transition to a state of peace and understanding.

The final kick in the teeth of his strangled Cordelia (Samantha Young) finds him immune to any more pain or pathos, though Hicks, carrying her corpse at the last, has no fears of those multiple "nevers" and "howls" that can sort out the men from the boys.

And the idea of perfidious Albion turning into a state-approved mental asylum is powerfully reinforced by the well-contrasted pair of Charles Aitken's athletic Edgar and his bastard cousin, Tunji Kasim's devious and manipulative Edmund. The grim and grime of the play has been fully expressed in Jon Bausor's design and Jon Clark's unremitting lighting, and one has to say that the early signs at the end of last year of this company pulling together for the long haul are increasingly positive.

With actors like Darrell D'Silva as an unusually vivid Kent, and Kelly Hunter and Katy Stephens, both tremendous as Goneril and Regan, the ensemble is in good shape. And Hicks's Lear is as total and powerful a performance as was his Coriolanus for the same director. But what next for him? The soothsayer in Antony and Cleopatra, that's what, which is like following Macbeth with the Porter. Ah well, no small parts, I suppose...

To 26 August (0844 800 1110)