“Where’s your compassion?” “Nowhere you can get at it.” This frosty exchange between the open-minded Catholic priest and the formidable Sister Aloysius is at the centre of John Patrick Shanley’s Doubt, a short sharp shock of a play that was first seen Off-Broadway in 2004.

The setting is a school in the Bronx in the autumn of 1964 and this historical moment meshes several key moods of liberalising change: the recent Camelot era of President Kennedy; the civil rights movement; and the challenge to the Catholic Church of the spirit of ecumenism.

At the start, Father Flynn (Padraic Delaney) delivers a Sunday sermon about the virtues of living with doubts; you are never alone, he suggests. He teaches physical education and religion in the school where the head, Sister Aloysius (Dearbhla Molloy), is isolated in certainty as she inducts a new, fresh teacher, Sister James (Marcella Plunkett) into her obstinate ways.

Having set up his potential for conflict, Shanley then kindles a fire by introducing a plot line rife with ambiguity and danger: Father Flynn has been seen with the school’s one black pupil in a private meeting. The boy has been drinking altar wine. Father Flynn is summoned by Sister Aloysius.

Father Flynn wears his nails long and takes three lumps of sugar in his tea. That strikes me as nothing at all, but it’s enough for Sister Aloysius (we used to have a Jesuit teacher at my Catholic grammar school whose idea of heaven was a Nat King Cole LP and an apple, but he seemed alright). With recent revelations about large-scale child abuse in Catholic education in America, the witch hunt by the reactionaries seems almost justified in retrospect.

But another complication arrives in a great scene between Sister Aloysius and the boy’s mother (beautifully played, with simmering rage and dignity, by Nikki Amuka-Bird) who reveals that the 12-year-old boy is indeed “that way” and needed a friend because of his violent father. This propels the play to a surprise conclusion still fraught with uncertainty.

Nicolas Kent’s production turns the screw at all the right places, though the acting of Delaney and the usually more luminous Molloy sometimes verges on the monotonous. John Gunter’s neat but clunky set moves between pulpit, school garden and Sister’s office with noisy efficiency.

The 80-minute play seems contrived until the resonating power of it breaks through; and then it packs an emotional and moral punch not dissimilar to Terence Rattigan at his best in boy-centred plays like The Winslow Boy and The Browning Version, the difference being that here, we never meet the young man himself.

- Michael Coveney