The Donmar Warehouse effects an extremely smooth and seamless transition from old to new regimes in which the new artistic director Michael Grandage shines a new and dazzling light on an old text and reveals a freshly sparkling gem, just as his predecessor Sam Mendes was so adept at doing.

Grandage has given this gleaming treatment to one of Noel Coward's earliest plays, The Vortex. First produced when the playwright was just 25, the piece was nearly banned by the Lord Chamberlain who declared, "This picture of a frivolous and degenerate set of people gives a wholly false impression of Society life".

Coward's typically witty reply to the Evening Standard was to capitalise on the stereotype: "I am never out of opium dens, cocaine dens, and other evil places. My mind is a mass of corruption. That brittle flippancy and daring outrageousness - and the ping-pong dialogue of witty rebukes in his plays that made him the natural successor to Oscar Wilde - of course belied Coward's more serious intentions.

The Vortex is a portrait of society in miniature, where appearance and the pursuit of being constantly amused (and amusing) were all. But what is the cost of living lives of constant denial? Peeling away the surface glitter here, Coward uncovers a highly damaged, dysfunctional relationship between a mother and her adult son.

Florence Lancaster (Francesca Annis) is desperate to hold onto her youth and beauty, even if she can only see it by reflection in her young toyboy lover, Tom Veryan (Mark Umbers). When Florence's 24-year-old musician son, Nicky (Chiwetel Ejiofor), returns from a year in Paris with a fiancée (Indira Varma) in tow, a crisis occurs as the girl swiftly swaps her affections from him to Nicky's mother's lover. Mother and son both dumped, the stage is set for a blistering confrontation that finds them groping towards at last admitting some self-truths.

Behind the constant cries for cocktails, Coward dares his characters to expose far more urgent needs. And Grandage dares his actors to delve deep beneath their characters' artifices to present their real faces. "Don't be obvious about anything", says Florence's friend Helen (Deborah Findlay); and the joy of this production is that nothing is, not least the colour-blind casting.

Ejiofor swaps the Rastafarian ramblings of the black psychotic patient in Blue/Orange to now assume a cut-glass accent and suit as Nicky in a performance that confirms him as Britain's fastest rising new stage star. As his mother, Francesca Annis - whose own real-life partner Ralph Fiennes is nearly 18 years her junior - strikes a potentially autobiographical note in taking a younger stage lover but proves her irresistible attractiveness behind the growing insecurity.

In an outstanding production, the entire company are brilliant, but the beautiful Indira Varma, the always superb Deborah Findlay and Bette Bourne (as the louche Pauncefort Quentin) make strikingly individual contributions. This is the best reclamation of a neglected Coward play since Semi-Monde.

- Mark Shenton