Polly Stenham’s update shifts Strindberg’s explosive play about class and sex from nineteenth century Sweden to contemporary London. We’re in a mansion off Hampstead Heath. Julie – played by Vanessa Kirby – is a damaged rich kid who’s celebrating her 33rd birthday by throwing a thumping rave for a bunch of posing hedonists. There’s an increasingly desperate edge to her search for pleasure as, fresh from a breakup, she flings herself into this wild, comfortless cavorting.

Below them, in the chic open plan kitchen, the help – Jean (Eric Kofi Abrefa), the family’s Ghanaian chauffeur, and his fiancee Kristina (Thalissa Teixeira), the Brazilian maid – tidy up and hold fort. She’s clearly knackered; he illicitly samples a bottle of his boss’s Chateau Latour. Then Julie comes down and hauls John off to the dance (“It’s my birthday, it’s the solstice. Let’s get pagan”), initiating a power game with him that will lead to sex and a savage struggle to the death.

Stenham has let it be known that part of her intention is to look at the hypocrisies of middle class liberals in relation to the ill-paid immigrant workforce on whom their moneyed lives depend. I can imagine her writing a wonderfully abrasive play of her own on that subject.

She demonstrates a very good ear here for the kind of friendship (“You’re a star”; “I’m so proud of you”) that the privileged can cultivate with their staff – not hypocritical or strategic, exactly, but incurious about the whole picture. And she gives Kristina a strong speech near the end about how the faux-chummy Julie has robbed her of that tiny bit of dignity that was all she possessed: “I don’t think you even knew I had it. That I need it.”

In general, though, I was left puzzled by her use of Miss Julie as a template. It doesn’t offer her much room for manoeuvre and, as she has reconceived it, the dramatic stakes are lowered. In this version, Julie is a trustafarian who is still living at home with her wealthy papa, popping Xanax, snorting cocaine, and evidently not leading a terribly sheltered life – “I hold your hair up when you’re sick. I pick you up after your abortion,” says Kristina in that same speech.

So no great taboo is broken here by her having sex with a black chauffeur. When Jean asks if it would be possible to live together under the same roof as her father, Julie is indignant: “What do you think he is? Some sort of... Tory?” Yet they persist with their fantasies of flight to Cape Verde.

Kirby excels at playing this latest addition to the echt Stenham gallery: the posh lost soul wild child who is paying the penalties of privilege and personal trauma (the discovery of her mother’s dead body). Floating around barefoot, she’s brilliant at the accents of off-hand entitlement and those scraps of fashionable knowledge that are like an airily waved fag. I laughed out loud when she put a stop to some unwelcome, conversational development with the vague, would-be seductive “it’s all a construct”.

There’s a glamorous tenacity about Kofi Abrefa’s fine Jean who certainly has her number, telling Julie that “to torment yourself like this is a luxury. To have the f***ing time.”

Carrie Cracknell’s production of this 80 minute piece is surprisingly low on sexual tension, though, and it makes some bad misjudgements. The pet canary in the Magimix, for example – a bird that makes not a peep of protest when Julie obeys Jean and pops it into the blender. The resulting red liquid looks like the basis of a new cocktail (a Canary Wharf, perhaps)? It says a lot for Kirby that her portrayal survives this “inventive” directorial flourish.