A dysfunctional American family. A cast of carefully drawn, fatally flawed characters. An undercurrent of burning ideological conflict. You’d be forgiven for thinking that The Long Road South, which has transferred to Islington’s King’s Head after its 2014 run at the Hope Theatre, was another rediscovered Arthur Miller play, a la No Villain, which premiered last month at the Old Red Lion. But it isn’t Miller, it’s Paul Minx, an American playwright who with The Long Road South has produced a play that delves deep into both the psychological, the political, and the philosophical.

Set on the patio of a middle-class white family’s suburban home in 1960s Indiana, The Long Road South presents Andre (Cornelius Macarthy), a devout and thoroughly decent African-American manservant to the Banks family. Playfully flirted with by his coquettish young charge Ivy (Lydea Perkins), bullied by her tyrannical father Jake (Michael Brandon), and perpetually nagged at by his girlfriend Grace (Krissi Bohn), Andre is beset on all sides by tests of his seemingly boundless patience. When the news of his imminent departure for the Civil Rights Movement in Alabama escapes, he finds himself facing an uphill battle against tears, stubbornness and prejudice.

Minx, like Miller, has a real talent for capturing a captivating air of authenticity. His characters are rich, full of detail and utterly real. When they converse, they do so with an easy, natural dialogue and when their anger flares or their tears flow, they shout and cry without any sense of artificiality or contrivance. Minx’s writing has an understated, dry humour too, which is perhaps overused at times but which nonetheless provokes laughter consistently.

He is helped by a strong cast, led by Cornelius Macarthy who, as Andre, cuts a compelling figure: noble, sturdy, with a troubled past and a deep, drawling voice. Listening to him is, as Imogen Stubbs’ alcoholic, borderline bipolar mother accurately calls it, “like stepping into a warm bath”. There is good support from Perkins as Ivy, a vivacious teen on the cusp of sexual maturity, and from Brandon as the ill-tempered all-American businessman-father.

Sarah Berger’s production uses the versatile space of the King’s Head well, and Adrian Linford’s set is strikingly detailed. It is perhaps too lurid to complement the performance’s naturalism perfectly, but it still effectively conjures up a claustrophobic, suburban setting.

Like most Miller, The Long Road South uses family drama to examine wider philosophical and political ideas. The ideological conflict here is not between socialism and capitalism like in Miller, however, but between prejudice and equality. This is perhaps not quite explored as deftly as it needs to be – one is left searching for a subtext, rather than reeling from it – but the play is nevertheless absorbing throughout.

In this, it is reminiscent of Miller’s The Man Who Had All The Luck, which received a rare airing at the King’s Head back in September and which struggles from the same problem. The underlying conflicts are muddled up in a glut of superficial detail and the conclusion is slightly unsatisfying, slightly anticlimactic as a result. A touch more elegance and The Long Road South would pack a much heavier punch.

The Long Road South is playing the King’s Head Theatre until 30 January. For more information and tickets, see the www.kingsheadtheatre.com