Peter Finch. His entry in the biographical dictionary of film might read, British thespian, Hollywood star; a philandering soak and force of nature. A volcanic talent whose rebellious streak and eternal quest for escapism, in the bottle or the bosom, became literalised when he moved to Jamaica and married local girl Eletha Barrett.

Finch’s peers cocked a snook at his interracial union, caricaturing it as the act of a belligerent contrarian conditioned by animal instinct; a predilection for the exotic or forbidden. The actor and his wife were subject to a noxious mix of surreptitious and balls out racism, then. And it’s this, suggests Adrian Hope and Cassie McFarlane in their new play, that introduced Finch to the only kind of impotence he’d ever known – namely rage. Said rage, vividly invoked by Stephen Hogan in a commanding turn as Finch, with notes of Leonard Rossiter and Rudolph Walker, found its truest expression in his last major film role, that of iconoclastic news anchor Howard Beale – the tortured mad preacher of Paddy Chayefsky’s Network.

Mad as Hell, supposing a real world dissatisfaction to match that of Beale’s, finds it in Finch and Barrett’s relationship. Intimately and sensitively built, in the Jermyn Street Theatre’s close quarters, it’s a heartfelt and three dimensional portrait of an unlikely coupling. The play doesn’t shirk from talking about the sexual politics of colonialism. It’s uncomfortable but it’s right that Barrett, given ebullient form by Vanessa Donovan, pushes back on this point, teasing out the actor’s motives. And we’re invited to reflect on Finch’s (hopefully non-fetishized) relationship with Debbie, a black liverpudlian singer (Alexandra Mardell) hoping to ride him all the way to the top.

But Hope and McFarlane ultimately choose to take Finch and Barrett’s relationship at face value. So we’re sure, the star’s visibly shaken by news of Martin Luther King’s murder and launches an impassioned defence of Bob Marley when his middle class wife writes off the singer as lower caste. Peter Finch was many things, we’re told, but no racist – inverted or otherwise.

We’re left to relish a paradox, the union of a free-spirited and hitherto untameable white atheist with a conservative, church going Jamaican woman – though one not immune to the material trappings of the Hollywood life Finch provides. It’s a fascinating dynamic and in the hands of Hogan and Donovan, so real you can almost taste the Caribbean air.

The production deserves credit for not heading down the obvious route of showing Finch and Barrett subjected to barrage after barrage of snobbish bigotry. We hear about these incidents but ultimately the play builds Finch’s anger in a more nuanced fashion.

It’s there in the character’s insecurities and weaknesses, a siege mentality built from many years of estranged detachment from the glitterati of the film industry. All the while his wife’s strength of character and complementary bullish temperament acts as a bulwark.

It’s telling that when the time comes for Finch to channel Beale (pun intended), he asks his wife to stay away. Howard Beale was a man who’d had everything he loved taken from him, a man shaking a fist at the world. The play’s greatest insight and piece of biographical excavation is that Finch needed to feel his wife’s absence to hit that mark.