Nichola McAuliffe: 'This being the Edinburgh Fringe our auditorium is what's fashionably called a 'space''

The general rule in theatre is that the more serious the piece, the more riotous the times had by the cast. The grim self-absorption of West End Wendys contrasts starkly with the glorious silliness of the average Dame or Knight. So, following this theory, it's no surprise that A British Subject, the true story of the final days of Mirza Tahir Hussain on a Pakistani death row and the campaign to save him has given us, the cast, more laughs than Paul Merton's stand up.

The intensity of the emotions on stage easily dissolve into barely suppressed hysteria when the condemned prisoner, whose only possession is a blue bucket, produces from it a copy of Sudoku for beginners and a packet of gypsy creams. But any pretence of self control was obliterated by the the squirrel.

This being the Edinburgh Fringe our auditorium is what's fashionably called a "space". Unfortunately, the roof of this crucible of creativity is supported by a wooden beam, which proved an irresistible playground for an adolescent tree rat. And, like most teenagers, when it got into trouble and couldn't find its way out, it started to make trouble. While we tried to tell the tragic story of a young man about to hang, the squirrel emitted a series of screams.

Just as we were about to stop the show, George Bishop, the public school educated assistant to the lighting designer, swang into action. Like a young Indiana Jones he bestrode the seat backs and, hanging from a lighting bar with one hand, he grabbed the squirrel with the other. His firm grip didn't fail as he bore the rodent above the heads of the audience and into the street – where most people would have put it out of our misery with a swift blow from a complete works of Shakespeare. But no. The young Englishman, strong but fair, carried the squirrel to a tree and gently attached it to the bark.

'A British Subject', Pleasance Courtyard to 31 Aug (0131 556 6550)