A new Ackbourn drama is invariably something to savour and this one is a laugh-out-loud winner.

The story is simple. A nine-year-old girl, Winnie, accompanies her heavily pregnant mother Laverne, to her cleaning job in North London.

Winnie is off school with a sore throat and her mother instructs her to sit quietly and get on with her homework, an essay on My Wonderful Day.

The other crucial factor is that Laverne (Petra Letang) insists Winnie speaks French all day on Tuesdays so that she is competent in the language when (if) they return to their ancestral home in Martinique. Winnie knows this to be a probably unattainable dream but goes along with it to keep her mother happy.

Ayckbourn makes us see the tempestuous life in the home of an irascible and adulterous TV producer through the innocence, and wisdom, of the child.

It is a brilliant performance by Ayesha Antoine as Winnie whose body language, the tilt of her head the rolling of her eyes and the fidgety feet, reveal what she thinks of adults behaving badly and dutifully writes it all down, from the bus journey in the morning, to the wife throwing the mistress naked into the street.

The adults are confused by her speaking French and then carry on as if she wasn’t there or treat her as if she was an imbecile. Terence Booth as Kevin the TV producer, whose foul mouthed tantrums, are a revelation to the nicely brought-up child, personifies egocentricity.

Ruth Gibson, the mistress, makes us squirm with her patronising high pitched tone when she speaks to Winnie. Paul Kemp, the business partner who thinks she doesn’t speak English, is similarly toe-curlingly gauche in his attempts to be avuncular.

Alexandra Mathie, as Paula, Kevin's wife, is the least obnoxious of the adults - bad tempered, but at least showing conern for Winnie. Mathie makes a positive impact in a relatively short appearance.

The play is at Bath until Saturday. Don’t miss it – it’s a tonic.