Breathing, Latchmere Theatre, London

The average rate of breathing for a man is 11 times a minute. So Gloria is in the terrible position of being able to calculate the number of breaths that are left for her son, Joe. After languishing for 19 years on death row in Texas, convicted of murder, he is about to breathe his last. But instead of being outside the prison with the protesters, Gloria, a black woman who teaches painting, is marking the occasion with a strange starlit picnic on a Texan beach with her white friend Marie.

The reasons for that and for the strong attachment between the two women emerge in the course of Breathing, a powerful new play by the young, London-based dramatist Jennifer Farmer. Two conversations at the beach, separated by 20 years, are artfully interwoven in the piece. The second involves a young couple who, by degrees, are revealed to be Marie's daughter, Kelly, and Joe. We are thus given an uneasy simultaneous view of devastating emotional consequences and of the build-up to the actions that led to them.

Wonderfully eloquent in her half-spoken distress, Lauren Fales's Kelly chafes at the narrow-minded conformity of her hometown and dreads winding up like Mom, who has nothing to show for her pains but three kids and a dead-end job as a burger-flipper. Black but from a better background, Joe (Darren Hart) finds it hard to admit to the relationship at home; he secures the kind of college place that she has pined for, and his dated idea of a shared happy future would leave any girl of spirit gasping for breath.

Farmer seems to have found the younger generation harder to write about. Joe is lumbered with lines that ring clangingly false, such as: "What's so special about being different? Look what happened to Icarus." And the echo of his mother's past that drives him to murder comes over like a hasty contrivance. That one's response to this piece is, none the less, overwhelmingly positive is a tribute to the striking empathy with which Farmer imagines her way into the bowels and hearts of mothers bereaved and about to be bereaved of their children.

Nichollette Collins's excellent Gloria is elegant, amusing and thoughtful, yet she shows you a woman so primitively connected to her son that she refuses to generalise from his case or assist those who would turn him into a political cause.

Marie, who in Paddy Navin's vivid performance is a splendid mix of outward gutsiness and inward fear, has written to the mother of her daughter's murderer. From this overture has sprung a friendship that here, as the execution draws closer, starts to come unravelled, no longer salving Marie's bad conscience about being an inadequate mother, or granting stoi- cism to the distraught Gloria. Well attuned to the tricky cross-cutting rhythms of the piece, Paul Higgins's absorbing production digs unmelodramatically and deeply into the primal grief and pain of these women.