Brighton-based Broken Silence Theatre bring their latest production, Necessity, to Clapham’s Bread and Roses following a sell-out run at last year’s Brighton Fringe. Inspired by a real event, Paul Macauley’s play tells the story of Patrick and Mish, a young couple faced with an impossible decision when a letter intended for their next door neighbour is delivered to their flat in error. Their ensuing struggle to decide what to do with its potentially explosive contents, whilst carefully observing – and judging – their neighbours’ troubled marriage, reveals hidden tensions in their own relationship that they might have preferred to keep buried.

This suburban drama is quietly intense, with a few surprises along the way and a twist ending that simultaneously brings the story back to where it started and leaves us dangling off a cliff. It’s a story about appearance versus reality – both couples are doing what they think society expects of them: buy a house; get a job; have a family. But it turns out doing what’s expected isn’t always the secret to happiness, and both relationships bear cracks hidden only just beneath the surface, waiting to be uncovered by something as seemingly innocuous as a letter.

The characters are complex and surprising; there’s nothing predictable about this play. Alex Reynolds makes a brief but memorable appearance as the letter-writer, a vital role that lights the touch paper and leaves it to burn. Will Anderson, a new addition to the established cast as Stephen, captures the weary resignation of the henpecked husband – but our sympathetic view of him is marred by the early revelation of his secret past. And Vicky Winning is easy to hate as the stuck-up Veronika, although she too catches us off guard early on with a moment of kindness that doesn’t quite gel with the thoroughly nasty piece of work she ultimately turns out to be.

Mish and Patrick seem like a happy enough couple as they share relaxed, light-hearted banter after a long day – but it doesn’t take long for old tensions to resurface. Aspiring jewellery maker Mish wears her heart on her sleeve, and is easily the most likeable of the four main characters because of that; Cerys Knighton slips from joking around to anger to total heartbreak without hesitation. But perhaps the most intriguing performance comes from Tim Cook as Patrick, simply because it’s impossible to tell from one moment to the next if he’s a loving husband or a bit of a psycho. Or maybe both.

One little niggle: it was sometimes hard to keep track of the story’s timeframe. There’s a suggestion that the action’s taking place over a matter of weeks, but that’s hard to process when one minute the neighbours are enjoying a summer barbecue, wearing shades and complaining about the heat, and the next they’re wrapped up in jumpers and winter coats. It’s a small detail, but noticeable enough to be distracting (to me, anyway; these are the sorts of things I worry about).

Simply staged and sensitively written, Necessity is a play that touches several pressure points about modern life (career, family, class, the awkwardness of socialising with your neighbours) while still keeping us entertained and in suspense until the end. And while most of us will never find ourselves facing this particular scenario, the play nonetheless leaves its audience with plenty to think about.