From its bang-slam opening with Peter Lindford’s Jean and Kristin Hewson’s Kristin wielding blades, Nick Philippou’s production of Strindberg’s sex-and-class shocker repeats visual images of falling and climbing, backed by thudding and eerie sounds of violence. Kate Fenwick’s Julie floats with childish, guilty pleasure through the kitchen door to mix with the servants.

Sex between her and Jean is hate-filled and half-glimpsed through savage images. Strindberg placed the act offstage, its rough mood suggested by a bawdy mob of drunken rustics erupting into the kitchen. Economics often mean this crowd is reduced to a sound effect but Philippou, with education animateur Pete Bailie, has worked with local groups to provide a contrasting innocence that defines Strindberg’s main characters even as it defies his stage directions for a randy dance.

The 13 to 19-year-olds providing this “Ballet” (Strindberg’s term) in Bury St Edmunds came from Bury Youth Theatre, drawn by the chance to work at the town’s Theatre Royal with professional actors. Three days’ rehearsal for their two-minute scene eventually proved worthwhile. “We did a lot we haven’t performed,” says one participant, “like a day in the life of our character. ”

The scene was carefully devised and groups told clearly there was no room for spontaneous improvisation.

The production adds irony, two lovers resting by the door behind which Julie and Jean are fighting tigrishly while another couple invade Kristin’s room, waking her. Clearing the crowd out Kristin sees evidence of Julie’s presence and works out what’s happening behind Jean’s closed door.

When she emerges much later the point where usually she deduces Jean and Julie’s sexual adventure she is already aware of it. This makes her far more calculating in her moves in the last part of the play.

They do not speak, and are on stage only briefly, but the young people’s impact on the play is considerable and they can rest assured that their three days’ rehearsal have not been wasted.