Sian Reese-Williams and Abdul Salis
Sian Reese-Williams and Abdul Salis
© Richard Davenport

Procrastination, as Hamlet proves, can be surprisingly compelling. In Lungs, Duncan Macmillan essentially spins out one prolonged decision into an entire 80-minute play, depicting the relationship of one couple from the perspective of a single conversation. As a dramatic device, it's astonishingly effective.

M and W – they are never given names – are thinking about starting a family. It seems like the logical next step in their lives together. As soon as they start talking about it, however, the decision of whether or not to have a child becomes increasingly complex. And as if it weren't enough to contemplate the prospect of bringing a new human being into the world, the choice of this one couple is also presented as having ramifications for the future of the entire planet. If you really care about the environment, why would you lumber it with another carbon footprint?

The protagonists' agonised journey through uncertainty is presented as a continuous conversation. Hours, days and even years are skipped past as the dialogue continually picks up where it left off. This could be confusing on stage, but George Perrin's production is careful and precise, quickly establishing its own clarity. Wisely, it does little with the circular space of the Roundabout, simply allowing performers Abdul Salis and Sian Reese-Williams to orbit slowly around one another.

Through this narrative of indecision, Macmillan manages to put a poignantly human face on debates about climate change and population control. There are brief moments when his characters feel a little like mouthpieces, rehearsing the sort of arguments that can be found in the sheets of newspapers and climate science journals. For the most part, however, their anxieties are painfully believable.