‘Lungs’ at the Old Vic. Photo: Helen Maybanks

M (Matt Smith) and W (Claire Foy) are an Ikea-frequenting couple. He’s a musician, she’s a PhD candidate. They’re at the stage of living together and no longer clubbing together, which means they’re also around the bump-discussing stage. Which is precisely what M does one day when they’re in the IKEA queue.

Here are some other things to know about them: soon after having the bump discussion, M stops working as musician and instead takes an unspecified corporate job. W keeps some of the excitement in their relationship alive by making an impromptu weekday picnic for M to join her for on his lunch break. After eating the iced donuts, they fuck in some public loos because: they’re looking to create a bump. The problem is that when the bump arrives in their relationship it’s a more of a metaphorical bump than a literal one. The kind of metaphorical bump that causes them to career off course into a metaphorical ditch.

Here’s one other thing to know about M and W: their story isn’t just about bumps. And as an extension of that, it’s not just about whether it’s right or wrong to create a bump given the state of the environment and world. It’s really about one question or one statement:

We’re good people, right?

There’s no magic formula to Duncan Macmillan’s play about M and W, but there is, somehow, one hell of a lot of magic. Strictly speaking, it’s a pretty simple piece about typical people doing typical things (a bit like Sally Rooney’s aptly-titled novel Normal People). Format-wise, it can’t lay any strong claim towards excessive originality – it’s structured as one long back-and-forth between the two characters who interrupt, overlap and second-guess each other. The same way that, on paper, Matthew Warchus’s neat and tidy production that positions M and W between a bubble of stage lights and a flooring of solar panels, doesn’t sound all that remarkable. Despite being written in 2011, its themes feel more ‘now’ than they did eight years ago – the whole thing could loosely be described as ‘Constellations for 2019′ with more climate change and less chronic illness. And yet, like the difference between your soul mate and your boyfriend, both play and production have something out of the ordinary about them. As in, they feel like more than the sum of their parts. They’re subtle, understated, funny and very, very watchable. Which is perhaps why the sentiment that keeps being repeated gently washes over you rather than hitting you fully in the face:

We’re good people, right?

One of the biggest things that makes the play and production better than perhaps they should be is the performances. It’s fascinating watching the same pair of actors play a different set of characters, but Lungs isn’t just an extended fan-fest for fans of The Crown. Smith is louche, charming, slopey-shouldered and relaxed. It’s never quite clear how genuine he’s being when doing things like, well, raising the initial idea of a bump while standing in the Ikea queue. The easy attitude of knowing-things-will-work-out-OK (simply because up until now they always have done) seeps out of him. He’s more of a blank slate, more of an archetype than Foy’s W. She conforms to stereotypes too – in particular the prickly, panicky middle class worrier with nothing really, ultimately, to worry about – but Foy’s performance is nuanced enough to make the woman likeable and human so that when she looks up and M and says:

We’re good people right?

It’s hard to know what the answer is. Because, yes, they’re both avocado-eating wankers over-brimming with hypocrisies like maggots in an old apple. But slapping that sticker on them is reductive and a bit boring. The ‘goodness’ they keep trying to check in about, isn’t just the goodness that comes from trying to offset a carbon footprint, it’s also the goodness of”¦ loving somebody. And carrying on loving them over the years as you both grow older and change. Loving someone while the planet burns to a cinder, or they’re ill, or there’s someone new and sexy at work, or your life-plans incur a major glitch. That very, very small goodness that almost impossible to tell if you’re doing right.

Lungs is on at the Old Vic until 9th November 2019. More info and tickets here.