Nicholas Gecks as Matthew in Denial at the King's Head Theatre. Photo by Christopher Tribble

Denial is based on a real-life case which, in the hands of a superb theatrical craftsman, has been transformed into compelling drama.

In her shocking and alienating opening speech, Jenny Young, played by Clare Cameron, establishes a character who is angry and vengeful to the point of hysteria. The play goes on to explore how this normal young woman with not unusual problems has become such a termagant.

Valerie Morgan, her therapist played with unshakeable conviction of her own righteousness by Sally Plumb, is central to the conundrum. Jenny’s ordinary, loving, good-enough parents, Matthew and Karen and their lawyer daughter, Abigail, are portrayed as ordinary people floundering and drowning in a poisonous situation.

As the entire family is destroyed, there can have been few in the audience who did not reflect that this could happen to them.

Performed in the round in this small pub theatre, Adam Spreadbury-Maher’s production involves the audience so closely it’s as if we are witnessing the destruction of people we know well.

It remains a mystery why Arnold Wesker, the playwright, was neglected for so long by the British theatrical establishment.

* Denial is at the King’s Head Theatre in Upper Street, N1, until June 9. Call 020 7478 0160 for box office.