THEATRE / Bloodied and still unbowed: Paul Taylor is chilled by Diana Rigg's performance in a creepy Medea

THE most chilling moment in any Greek tragedy that I have seen arose from Deborah Warner's superb handling of Clytemnestra's death - butchered by her own son - in Sophocles's Electra. Murder happens offstage in Greek tragedy and Warner achieved maximum horror by obeying the letter of this convention but slightly bending its spirit. Intent on the bloody deed, Orestes and Pylades enter the palace, its great tin wall closing after them. The nerve-shattering clashes as body hit metal, the screams, the thin gulley of water that bisected the stage suddenly flowing red - all this could hardly have made the act more obscenely present.

The huge wall of rusty sliding panels that dominated Jonathan Kent's powerful production of Medea when it opened last year at the Almeida, London, is taller and looks even more bleakly imposing on the stage at Wyndham's, London, where the show has been remounted. And if nothing quite as subtly horrible as that Electra sequence is made of the metal here, that's not to say that there aren't some authentically creepy and thought-provoking moments.

Peter J Davison's design suggests, in fact, an unflattering correspondence between Jason and his house: both are clangingly hollow. So, too, is Medea's victory over her sneering, chauvinist, hypocritical husband, bought only at the terrible price of slaughtering her own children. All this is conveyed direct to your nervous system in the stunning coup de theatre at the end. The bloodstained Medea is left, unreachable in her crowing but clearly comfortless pose as victor.

Diana Rigg is even better now in this title role, eliciting a continuously ambivalent response to this victim / villain. Take the wonderful moment when the news comes of the accomplishment of that piece of her plan which makes the rest inevitable. Rigg lets out a loud involuntary 'Ha]' that's hauntingly strung between bitchy triumph and wracked maternal torment. A stricken tenderness keeps colliding with the arch calculation in her manner. Not that this heroine fools herself. The chorus racks its brains for a parallel female infanticide and can only come up with Ino, whom the gods first drove mad. Rigg shows you a woman who would rather wreak havoc than be scorned by those she hates.

Tim Woodward makes a tremendous impact as a repellently macho, would-be domineering Jason. Kent's production has quiet subtleties, though, as well as force - the long sorrowing look, say, between the Old Nurse (Madge Ryan) and Medea, as the tragedy jerks implacably forward. Its pain and intimacy appear heartbreakingly impotent in a world where relationships are being wrenched asunder pitilessly.

Wyndhams, London WC2 (071-867 1116)