Jack Lowden explodes with energy opposite Martin Freeman’s sad dad in The Fifth Step

In a cautious era, David Ireland is British playwriting’s most prominent provocateur. His ink-black comedies are full of oddly lovable bastards who bulldoze their way into delicate issues like sexual abuse in the movie industry (2018’s Ulster American) or Northern Irish sectarian violence (2016’s Cyprus Avenue). There’s plenty to raise eyebrows in his latest at Soho Place, The Fifth Step, a brutal exposé of Alcoholics Anonymous. Still, it feels both softer and less purposeful than the plays that made Ireland’s name – a chance for Jack Lowden (Slow Horses) to deliver a persuasive rendition of a vulnerable, impulsive young guy who’s shamelessly manipulated by Martin Freeman’s older sponsor.

Lowden explodes with half-suppressed energy as Luka, an unemployed, sex-obsessed alcoholic desperate to pummel his wayward life into shape. Help comes in the form of James, a fellow AA member who’s been sober for decades, but this middle-aged sad dad isn’t always the best advocate for his booze-free lifestyle. The everyguy authenticity that has made Freeman a telly regular is lost a little here, in a slightly underwhelming stage performance. Instead, this play’s appeal comes from the hilarious clashes between Luka’s blunt literal-mindedness and James’s patronising obfuscation. “Cultivate a relationship with yourself,” advises the older man. “I thought you said I wasn’t meant to do that any more!” says Luka, battling to beat his 20-a-day masturbation habit.

As Luka lets go of the booze and sex addictions that once filled his life, other, weirder stuff floods in: hallucinations of Hollywood stars, beautifully rendered by Lowden’s impersonations, and a kind of strange quasi-Christian spirituality that clashes with James’s more dogmatic world view. In interviews, Ireland has spoken of his own relationship with alcohol: one that started young and ended with his last drink at the age of 23. Two decades of navigating sobriety later, his writing is full of insights into the loneliness it brings. AA advice is that Luka shouldn’t hang out in pubs or bars – but that leaves him lost, isolated from his friends, and bereft of places to meet women to start the kind of wholesome long-term relationship his sponsor advocates.

Like Ireland’s previous plays, The Fifth Step centres on the ugly clash between dogma and more complicated human realities. It’s gently fascinating, watching James flounder as his self-help AA platitudes do little to steer Luka away from his all-consuming obsessions, towards a more balanced kind of life.

Director Finn den Hertog stages things simply, in the round. You’d expect a set-up like this to offer plenty of emotional punch, plenty of space for characters to unfurl, but the tension between these two performers doesn’t simmer as it should. And since Ireland’s writing makes James feel unlikeable from the start, his eventual lurch into mild villainy comes as no surprise. Alcoholism, sobriety, spirituality: the themes are resonant here. But this is a production that puts its hands firmly round your neck without ever delivering the expected throttling.

‘The Fifth Step’ is on at Soho Place until 26 July