Sher is a dynamic revelation. Leontes is struck by suspicions so unfathomable that, once entertained, their momentum is unstoppable. But Sher's fight with internal demons is secondary to his tragi-comic struggle to remain outwardly assured in his role as avenger. Imagining the unimaginable is child's play. Implementing the unthinkable - the destruction of his family - requires concentrated obfuscation.
In Robert Jones's stylish, wood-panelled colonnade, under a sky of billowing drapes, Leontes eyes Hermione, his teasingly informal wife (Alexandra Gilbreath), imploring his boyhood friend, Polixenes, to extend his visit. Suddenly everything is as black and white as the crisp costumes of the frock-coated courtiers. Sher stands at the front of the stage, like a red-waistcoated music-hall compere, to consider the "disgraced" part he must play. Mischievously peering into the front rows, he points to a "cuckold", "his pond fished by his next neighbour ... Sir Smile". Then, like an overwound mechanical toy, the stand-up flippancy gathers force and mutates into a primal, chilling venom.
When Leontes confronts his pregnant wife in her chamber, he begins his accusations tremulously, almost thinking them through aloud. But, so swiftly do his imaginings consolidate his insecurity that an instinctive, tearful embrace of Hermione becomes a shocking shove to the floor. By the time Paulina, a magnificently indomitable Estelle Kohler, brings his new-born daughter to him, the walls of the corridor have already closed in. Now manic and sleep-deprived, Leontes is torn between neediness and necessity. Sobbing, he's drawn to cradle the baby; then he remembers his madness. The "bastard" is flung back down; Paulina and her husband are verbally abused and violently manhandled.
At the trial, accused and accuser are physically wrecked. Sher's faltering, distracted reading of a prepared statement betrays the majesty of his ermine robes and conviction of his judicial role. Gilbreath, haggard and wide-eyed in a stained prison sack, stumbles to the front of the stage; in a trance, she insists that "the Emperor of Russia was my father". It's as emotion-sapping as any of Sher's compulsive rages.
The sustained intensity of the first half was never going to be matched - or alleviated - by the rustic frolics in sunny Bohemia, where the illicit wooing of the young shepherdess Perdita, Leontes's abandoned daughter, by Polixenes's son sets in motion the partial reversal of the tragedy and the regeneration of its protagonists.
Overcrowded and overstretched, the jollity of the sheep-shearing party gets lost somewhere between the towers of wool-bales and the auditorium. But respect is due to Ian Hughes as Autolycus and Christopher Brand as the Young Shepherd for a scene of pure physical theatre. In a series of deftly executed moves - between actors who seemed to have a height differential of at least two feet - the Young Shepherd is unwittingly divested of not just his wallet but his entire outfit. Theatre de Complicite surely awaits them.
Speaking of which, it's time for a valedictory acknowledgement for Complicite's bastard sons. Hamish McColl and Sean Foley, aka Mr Puntila and his Man Matti, aka the right size, have just finished a three-week residency in the West End. Their inventive, irreverent and downright absurd take on Bertie Brecht, ably assisted by Lee Hall's fresh version and Kathryn Hunter's flawless direction, was one of the hits of last year's Edinburgh Fringe, and of the Almeida's remarkable run in 1998. Breathlessly fast and physical, its blend of slapstick and song, improv and role-play, politics and pathos was irresistible. These are people who can summarise Brechtian alienation theory in a tuneful little ditty: "It denies the viewing public Aristotlean catharsis/ Which means that you the theatre-going public/ Should get up off your arses."
And with that, it's out with the old centennial celebrations - the birth of Brecht - and in with the new - that of Noel Coward. Coward's first biographer, Sheridan Morley, is first off the blocks, directing a production of Coward's last full-length play, Song at Twilight (1966) at the King's Head in Islington. It's a semi-autobiographical piece about an ageing, ailing writer called Hugh Latymer, who is forced to confront his closet homosexuality when his first lover Carlotta hunts him down with incriminating evidence - letters to a dead, male friend who was his only true love - the piece still says much about current attitudes to the private lives of public figures.
Corin Redgrave, whose own father lived such a double life, plays the self-centred Latymer with disdainful and pathetic bitterness. He's an imposing presence - but there's not much room to be anything else. The cramped King's Head set resembles a tatty restaurant foyer more than "a private suite in a luxurious hotel", and the camp waiter has to execute a series of agile turns in order to get through the door and precariously put the large dinner tray down on a tiny drinks table. With no space for movement as the exchanges between Latymer and Nyree Dawn Porter's Carlotta reach their inevitable climax, Coward's impassioned ripostes are stilted and lack sparkle, and Porter's delivery is fatally faltering.
It's left to Kika Markham, as Hilde, Latymer's wife of 20 years, to set up the play's most interesting dynamic. Resilient and all-knowing, she batters Carlotta's manipulative scheme out the door with a moving speech on the meaning of loyalty and love. As the two women take over negotiations on the future of the letters and Latymer, Redgrave's silent contemplation of his much-maligned public shield is a study in emotional dependence and tearful gratitude that betrays the hitherto unseen self-knowledge demanded by Carlotta.
'The Winter's Tale': Stratford RST (01789 295623), to 4 March; 'Song at Twilight': King's Head, N1 (0171 226 1916), to 24 January.
Robert Butler is away.