Daniel Ryan (Daniel) and Samantha Spiro (Peppy) in The House They Grew Up In
Daniel Ryan (Daniel) and Samantha Spiro (Peppy) in The House They Grew Up In
© Johan Persson

Hoarders gonna hoard in Deborah Bruce's new play. As the rest of us Marie Kondo our way to mindfulness, she shows us two lives swallowed up in a sea of old stuff. Daniel and Peppy, brother and sister, live knee-deep in clutter. They've all but disappeared beneath the detritus in their living room, decades' worth of it. Sagging laundry bags. Piles of yellowing paper. More saucepans than you've had hot dinners. It's a sad state of affairs.

A stressful watch, too – and not just because Max Jones' set is so stuffed full of stuff. Samantha Spiro's Peppy clatters around, never less than full fluster. Incapable of following a task through, she'll peel a potato twice then put it down, her attention snagging on something else – an encyclopedia, perhaps, or some stray thought. Spiro plays her with a squint, as if her eyesight is shot from years of searching. Or is it a grimace? A face frozen in disgust. She clatters around in a natty wool jumper, beneath a thicket of gray hair, rattling a ladel against a metal bowl and calling out for her cat, Charlie Brown. No sign. Still.

Daniel, too, takes constant attention. A 40-something with behavioural difficulties, he sits in his armchair and slips into long silences, shutting the world out with his headphones and stroking his beard. He needs constant checking in on. The pair, essentially, drive each other potty, exacerbating each other's issues in a vicious cycle. Even their conversations drift into tangents and fall into loops. It's almost unbearable: Beckett at large.

Theirs is a chicken-egg situation. Peppy put her life on hold to care for Daniel, leaving Cambridge when their parents died, yet her finicky approach to care may have held him back in turn. Both the state of the house and the state of their heads invoke the past. How, you ask, did it come to this? And how will they ever break the cycle? 'We're falling apart,' says Peppy, all too aware of the problem, but powerless to prevent it. It's like locked-in syndrome: conscious paralysis.

Change starts with a child. Their next-door neighbour Ben, eight, has struck up an unlikely friendship with Daniel, superbly played by Daniel Ryan, and, when the kid sneaks over one night to stay, it triggers a police search that opens up the pair's private world. That's the big problem with Bruce's play. It's best at its most claustrophic, confined to one clutter room. Her plot lets air into Jeremy Herrin's meticulous production, and with it, a layer of artifice.

But Bruce uses Peppy and Daniel to reflect the changes of the last 30-odd years. They are, essentially, the pair that time forgot; a yardstick against which to measure our world and our attitudes. Even their language – numbskull, birdbrain – is stuck in the past, and sometimes they seem to have lost track of time altogether. They hoard more than objects. Daniel collects experiences in an exhaustive, obsessive diary; Peppy pores over encyclopedias, accumulating knowledge. This is a play that muses on value. Possessions have depreciated, house prices have skyrocketed – something Bruce overcooks with an opportunistic property prospector who pokes his nose in uninvited.

Beneath it all, the play's a plea for care, and a damning indictment of a society that clears out its clutter, people and all.

The House They Grew Up In runs at the Minerva Theatre, Chichester, until 5 August.