It Felt Empty When the Heart Went At First But It Is Alright Now, Arcola Theatre, London

The real secret diary of a call girl

Dijana has some new bottles of L'Oréal shampoo – bought, or rather nicked, from Boots, because she's worth it. Being a 22-year-old, sex-trafficked Croatian, she's in a position to know precisely what she's worth, by one way of computing it, because she knows how much Babac, her lover-turned-pimp, paid for her. And she knows how much she still owes him before she can be re-united with her passport and the young daughter who is also his. When we first encounter her, in It Felt Empty When the Heart Went At First But It Is Alright Now, Lucy Kirkwood's wonderful new piece, Dijana is in her desolate Dalston prison of a room, awaiting the punter who (she hopes) will be her last.

The play was developed during the author's tenure as writer-in-residence at Clean Break, a theatre and education company that works with women whose lives have been affected by the criminal justice system. If you think that this will therefore entail a stern dose of political correctness or a bout of po-faced tub-thumping, then you couldn't be more wrong. It Felt Empty... is heartbreaking and angry, right enough, but there are flurries of appalling comedy here, too. And while grounded in scrupulously researched reality, it simultaneously takes us into the protagonist's subjective world, as the script and Lucy Morrison's wonderful promenade production follows Dijana through collapsed air vents and tiny Alice in Wonderland doors on her progress from one type of prison to another and then back into the past to that starry-eyed day when, still trusting Babac and five months pregnant with his child, she was looking forward to flying away on a foreign holiday.

With her huge, sensitive eyes and her delicate frame, the beautiful Hara Yannas is magnificent in the role. She is piercing, yet absolutely true to the script's conception of this girl as a grotesquely abused victim of one of capitalism's more hellish tricks, but not always a victim in her own mind's eye. The character is full (as well she might be) of coping-strategy self-deceptions; she's a little bit racist; she can convince herself that she's like luscious, pouting Billie Piper in Secret Diary of a Call Girl. But then, in the first scene, we see her bruised and branded body flung this way and that over the bed as she has intercourse with the invisible client and it harrowingly brings home how brave she is in her flaky bravado.

To the din of police raids, trapped flapping birds, and warped seaside-arcade noises, we move through transitional areas where bloodied fluffy toys dangle and into a vision of Dijana's former dream future, rendered as a sparkly wilderness of polythene-packaged white goods and banks of artificial flowers. But you never feel that anything here has been sensationalised. "Hypocrite voyeur", the production seems to say. And if can't continue "ma semblable, ma soeur", it's because it responsibly recognises that there are limits to which one can "identify" with a girl in such terrible straits. There's a terrific, impious comedy in the scene where Dijana finds herself sharing a cell with Gloria, an alarming West African woman (the excellent Madeline Appiah). Do they find sisterhood? Well, largely no, because Dijana now can't stand to be touched and Gloria is keen on big hugs as well as on unnerving lunges into talk about what you can sell on the black market these days. She ends up with a bitten cheek.

It's not a perfect piece (there are some tonal wobbles in the monologues addressed to the absent child). But It Felt Empty... passes the crucial test. You reckon that you could watch it in the company of an ex-victim and not worry that she would feel that art had got above itself and exploited the situation for its own ends.

To 31 October (020-7503 1646)