Neve McIntosh and Magnus Gilljam in The Events
Neve McIntosh and Magnus Gilljam in The Events

This is a fiendishly brilliant new play by David Greig, fresh from writing the new libretto for Charlie and the Chocolate Factory at Drury Lane, that alludes indirectly to the Anders Breivik massacre in Norway two years ago while creating a resonant theatrical framework – a choir rehearsing in a community hall – to discuss the matters arising.

And Ramin Gray's equally brilliant production for the Actors Touring Company (co-produced with the Young Vic, Schauspielhaus Wein and Bragetatret) uses the choir as a background and commentary to the dramatic enquiry, which involves a lesbian priest, Claire, who has survived an atrocity in a school perpetrated by a mystery loner attracted to the on-line campaign of a political party opposed to what they call state-funded propaganda for multiculturalism.

This loner, or Boy, in a magnetic performance of chameleon charm by Rudi Dharmalingam, is first seen as an Aboriginal youth watching ships from England sailing into his native cove. He also represents a tribal warrior, the mass murderer's father, his best friend, a journalist and the politician who dissociates himself from the consequence s of his own policies.

And he also stands in for Claire's partner, Katrina, who makes yurts; it's part of the play's generosity of spirit, and political optimism, to obliterate social and gender demarcation lines while giving even an evil killer, or terrorist, the credit for acting appallingly for some reason.

Survivors are victims too, of course, and Neve McIntosh is utterly compelling as Claire, trying to salve wounds in leading the choir in hymns ancient and modern – and, incidentally, a Norwegian coffee song – while trying to rebuild her life with the choir, who will be played by local groups wherever the company tours. Music is by John Browne, powerfully understated design by Chloe Lamford.

The Events continues at the Traverse until 25 August