Days Of Significance, Tricycle Theatre, London

Roy Williams's Days of Significance was one of the most powerful plays of last year, but it had a disappointingly limited run when it premiered at the Swan Theatre in Stratford. So it's good to report that Maria Aberg's excellent RSC production has now resurfaced at the Tricycle, in a revised version with a much more dramatically effective third act.

The Tricycle hasn't been reconfigured like the Swan to allow for an in-yer-face promenade staging. But there's still a dangerous physical immediacy to the proceedings as brawling, puking, willy-waving yob culture spills into the aisles.

With artful inversions of the set-up in Much Ado About Nothing, Williams first shows us a group of squaddies getting bladdered on the eve of their departure for Iraq. We follow them to Basra, where Jamie Davis's charismatic Ben, who has opened fire on a bunch of unarmed children, is fatally trapped in an alleyway with two comrades and a dying sergeant.

Then it's back to England, where the girl once dubbed Hannah the Slapper (movingly played by Claire-Louise Cordwell) overcomes her revulsion and, displaying a new emotional and political maturity, decides to stand by her former boyfriend, Jamie, during his trial for torturing Iraqi prisoners.

In terms of its message, the play performs a brilliant balancing act. It exposes and deplores the (supposedly superior) values that the soldiers are exporting, at the same time as suggesting that society has failed these ignorant, culturally stunted youths who are military fodder.

Williams has a remarkable talent for engineering unforced, truthful-seeming collisions between tragic emotion and irrelevant or blithely disreputable comedy. In extremis in the Basra alleyway, his soldiers can still find their attention distracted towards a dispute about Arsenal and Spurs.

Likewise, in the final scene, the violent ugliness of the reactions towards Craig Gallivan's Jamie and his cornered desolation cut all the deeper for the cheerfully vulgar, squiffy obliviousness of the happy newlyweds (hilarious Beverley Rudd and Simon Harrison). And there isn't a false note to be found in the expertly scabrous yet subtle performances of the terrific cast. Strongly recommended.

To 29 March (020-7328 1000)