This remarkable show, about the tensions and stresses of two men confined in an extremely small space, is inspired by the story of Brian Keenan and John McCarthy’s incarceration at the hands of Beirut terrorists in the 1980s.

In Greek mythology, Pandora ill-advisedly opens the box Zeus has given her, thereby releasing all the evils into the world, with only hope left in the box.

Wolfgang Hoffmann and Sven Till, of the German company Fabrik Potsdam, have reversed this, confining themselves in a box the size of a small lift, and taking in with them all their experiences of life, both good and bad with hope notably absent. This intense duet about varying emotions in close confinement is the first time these two have worked alone as a pair, and it’s a stunning performance.

The two, wearing something like prison uniform, are looking for somewhere to hide. Maybe they are on the run. They enter the box with its shiny interior and open front, and straightaway you can see that it’s a bit of a squash. At first it’s funny as they experiment, trying to fit their bodies in to comfortable positions.

Hands, limbs, even heads become intermingled until you can’t work out what belongs to whom. Boredom sets in, and they play a ludicrous game of hide and seek in which they pretend they can’t see each other; they imitate animals for each other’s amusement, constantly changing position, often hanging from the roof or high up the wall.

Cooped up like this, they float through playfulness, humour, frustration, despair, even tenderness towards each other.

There are hints of a sexual attraction between them, but this is quickly extinguished. In a violent episode, they throw each other against the walls, the ceiling and the floor in their fury, before discovering, finally, that escape is possible through the roof. But freedom to them is now as daunting as confinement.

Two men in a box for 70 minutes doesn’t sound promising as entertainment, but it’s riveting.