Any Given Day, Traverse Theatre, Edinburgh

Linda McLean's new play for the Traverse is actually two plays, a diptych in which the relationship between the two doesn't become apparent until very near the end, when we can see the full arc of these regretful, terrified, but somehow still hopeful characters sink into the depths of brutal despair, be lifted briefly by the promise of a good day amidst the misery and then find themselves inevitably crushed once more after the curtain has dropped.

Although it may not appear so for much of the duration, the piece is structurally as taut as the prison each player has in place of a life.

Bill and Sadie, portrayed with inarticulate tenderness by real-life brother and sister Lewis and Kathryn Howden, are a couple with learning difficulties trapped in their high-rise flat by a compulsive routine and the menacing hint of danger outside. Stones hit their reinforced glass windows and Sadie is terrified of the phone.

As we come to know and feel for this pair, we sense their vulnerability hanging over the room like the grey sky they see from their window. When this tension is broken, it does so with a snap of horrifying cruelty which is almost unbearable to watch.

Meanwhile, across town, barmaid Jackie is passed a cheering message from her boss, Dave, and takes him into her confidence about her unwell son, borderline drink problem and escape from her past life. In return, Dave offers her the briefest of respite.

Phil McKee plays Dave with a certain kind of charismatic smarm, which might be read as insincerity if one is feeling pessimistic – and one might well be by this point. Kate Dickie's Jackie, however, is all the hope and sadness of this play rolled in to one.

Those who recall the actress's performance in the film Red Road will know that her face can display beautiful vitality and resigned despair almost in the same expression. We want her, at least, to be all right.

Perhaps we're hoping in vain. As a psychological horror, this is an excellent play which truly does horrify on so many levels. As a portrait of Broken Britain, we can but hope that McLean and director Dominic Hill are happily veering towards grand guignol.

To 19 June (0131 228 1404)