How rare it is to find a new West End play with a seriously amusing mind of its own. Joanna Murray-Smith's The Female Of The Species may best be described as a farcical-comedy, but there's no missing the force, intelligence or incidental comedy of the attack Murray-Smith launches on that first heroine of feminism, Germaine Greer.

Nor are we allowed to lose sight of the playwright's conviction that women's liberation has left some women oppressed and depressed by feminist insistence upon what they should want out of life or try to be. Men, as Murray-Smith reveals them here, have been left scarcely more certain about what they should expect of themselves or their female partners.

Inspired by an unpleasant incident when a disturbed female student broke into Greer's home a few years ago, Murray-Smith invents an even more threatening scenario.

Greer does not, of course, feature in The Female Of The Species and the author insists all the characters have emerged straight from her imagination. Even so, Greer's spirit and aggressive personality, subject to comic, wounding caricature, haunt the play in the tart, self-admiring shape of Eileen Atkins's Margot Mason, an author forever changing her mind and author of a classic guide to women-power, The Cerebral Vagina. Murray-Smith's humour is typically prone to robust vulgarity and it comes as no surprise that Greer has, with that characteristic moderation of hers, already retaliated, damning the playwright as an " insane reactionary".

So there the foulish-mouthed Miss Mason stands in her country house writing room, with rich views of fields and cows, vainly trying to stimulate herself into making a fresh literary-feminist lunge. How about Clitorism as a title for her latest, unforthcoming book, she muses, pleased by the thought of inventing a new word, but before she can go further Anna Maxwell Martin's disturbed, young Molly Rivers, one of her forgotten students, walks in.

Although Molly flourishes a gun, then handcuffs and half gags the loquacious Margot, The Female Of The Species never becomes menacing. Instead the atmosphere in Roger Michell's well-pitched production turns farcical, flippant and funny. Molly is just the first of five uninvited visitors to arrive, each claiming to have been either adversely affected by Margot's commanding personality or her theories about male-female sexual relations. Sophie Thompson in terrific, comic form as Margot's despised, neurotic daughter arrives, overwhelmed by her children and Paul Chahidi's husband who takes her for granted but never shows himself to be the commanding male in bed she longs for. Con O'Neill's taxi-driver, who appears for no good reason, voices a similar belief that women do not really want domesticated partners.

The Female Of The Species would have been far more dramatic and provocative if Margot and her detractors had fought out their rival claims. Instead the splendid Dame Eileen mounts another witty display of brisk imperiousness and self-admiring froideur, effortlessly swatting away complaints as if they were mere gnats. It makes for an evening of wicked, educated and reactionary amusement.