THEATRE / Una Pooka - Tricycle, Kilburn

The year is 1979: it's the eve of the Pope's visit to Ireland, and everybody in Dublin has somebody sleeping on their floor. Aidan and Nuala have the whole Kevitt family up from the country - Aidan's pious tyrant of a mother, his malcontented brother Liam, and his reserved sister Una. And then there's his father's cousin, Fr Simeon, a self-effacing, bland monk. Everyone is primed with goodwill in expectation of the Holy Father's arrival; but, predictably, as the evening wears on, masks slip and tensions erupt.

Michael Harding's play comes across as straightforward, expert social comedy - a kind of Irish Catholic Ayckbourn. But it is really something else entirely. Halfway through the first act, there's an abrupt revelation that the action of the play is a flashback - 'now' is actually some time later, and what we're seeing are the events of that night as remembered by Una and Fr Simeon. At the same time, the mood switches into a darker, wilder fantasy - Simeon is not what he seems at all; and nothing that happens is even remotely predictable.

Apart from a baffling denouement, everything about Una Pooka is superb. It's a virtuoso piece, thoroughly unnerving and funny, its intricate time-scheme handled with exhilarating facility by the director, Nicolas Kent, and his excellent cast. In particular, Julia Dearden's sympathetic, steely Una and Roger Allam's magnetic Simeon are outstanding.

Box office: 071-328 1000.