Doubt: A Parable, Tricycle Theatre, London

Rarely a month goes by without fresh reports from the US about the Roman Catholic Church and its attempts to cover up the child-abuse cases brought (often decades after the fact) against priests. Committed as it is to the idea of divine forgiveness and the second chance proffered to the least of sinners, does the Church have the right to cheat the state of evidence that might bring the abusers to book and send a stern message?

It's intriguing that Doubt: A Parable – a play by John Patrick Shanley, which won the Tony and Pulitzer prizes in 2005 – opts for the dimensions of a chamber piece and comes at the topic from an unusual angle. In this British premiere by Nic Kent at the Tricycle, the play dramatises a battle of wills between its main character, Sister Aloysius (Dearbhla Molloy), the redoubtable old-style head of a mixed Catholic school, and Father Flynn (Padraic Delaney), the young and charismatic Irish priest and baseball coach whom she suspects of interfering with 12-year-old Donald Mueller, the school's first black pupil.

Caught between the two is a young, idealistic nun (Marcella Plunkett) who imparts the equivocal information that causes the clash and the muted cataclysm. The cast is completed by Nikki Amuka-Bird as the boy's mother. In one of the play's best, least expected confrontations, this character refuses to be scandalised by the supposed revelations and supports Flynn's protective friendship with her son. We never meet Donald and never know whose take on the situation is the most accurate – or least inaccurate.

Even more interesting is the playwright's evidently ambivalent response to Sister Aloysius, who is no simple monster, either in the clever script or in Molloy's excellent performance, which brings her alive as a watchful, leathery-with-experience, wryly conservative stickler for impersonal values – such as the idea that a teacher should not be a bleeding-heart performer but the catalyst that causes the pupils to perform.

The play is deft at showing how the battle between nun and priest exemplifies a larger ideological conflict. It also makes you aware that Sister Aloysius is frustrated by an institution in which priests always take precedence, even though nuns are often required to be twice the men that they are.

To 12 January (020-7328 1000)