Supermodels Twiggy and Jerry Hall became actors with a fair degree of success, and now the signs seem fairly good for their catwalk junior, 29 year-old Agyness Deyn, who makes a poised and promising stage debut as a free-living sex buddy in a rather shocking comedy of middle-class immorality.

Not least among the points of interest about The Leisure Society is that it comes from Quebecois writer Franҫois Archambault - a Montreal compatriot of Michel Tremblay and Robert Lepage – in a smart translation by Bobby Theodore, directed by a Pinter specialist, Harry Burton, and also starring Ed Stoppard, hotfoot from the new Upstairs Downstairs.

There’s a kind of cultural stamp and vintage about the short 90-minute event in the smaller of the Trafalgar Studios (the coffin, I call it) that is not let down by the reality of the show. Stoppard plays a bored, successful 30-something whose marriage to borderline alcoholic Mary (Melanie Gray) is slipping into boredom.

Their baby screams on the intercom which is placed on the un-played grand piano. They are being interviewed for adopting a little Chinese girl. And they have called round best friend Mark (John Schwab) to tell him they don’t want to see him again. He arrives with Deyn’s lissom blonde Paula and stays for dinner and a threesome.

There’s a certain amount of drunken friskiness, most of it offstage, around the swimming pool, in the bedroom (Peter is excluded from some explicit moaning on the intercom) and some nasty revelations about baby-shaking while baby-sitting on both sides; Mark’s ex-wife, whom we don’t see, and who’s had a nose job, was culpable, too.

It’s like a decadent, very funny, collaboration between Edward Albee and Yasmina Reza, with some witty linking classical musical played on steel drums and xylophone.

In a pathetic coda, Stoppard – who proves himself a surprisingly adept farceur in a performance of well-controlled attack – abases himself before Deyn’s cool, gazelle-like siren.

But the conclusion is not entirely unsavoury, and redemption not impossible. Melanie Gray is marvellous as a woman spoilt for options in her private life – we never know what these people actually do for a living; “we don’t drink, we have a child” – but hanging by a thread to her innate sense of decency.