As the lights go up on Pests, you may be forgiven for believing you had accidentally stumbled into a time warp. Developed in collaboration with Clean Break, this intense two-hander from Vivienne Franzmann (Mogadishu, The Witness) resembles the kind of short, sharp shock of a play that was the raison d’être of new writing more than a decade ago. The fact that it has been directed by Lucy Morrison, who has previously worked with Mark Ravenhill and Sarah Kane, probably has something to do with this. This isn’t to suggest Pests is old-fashioned per se, since the subjects it sets out to dramatise – drug abuse, sexual violence and social deprivation – have hardly faded with the end of the nineties. And yet there is something peculiarly anachronistic at work in this play’s predetermined desire to wear us down and shock its audience into submission.

Pink (Sinead Matthews) and Rolly (Ellie Kendrick) are sisters and both the victims of abusive parents. When a pregnant Rolly returns from prison to her sister’s ‘nest’, Pink must fulfil the role of hunter-gatherer and protect her little sister. However, when Rolly decides to fly the coop for a job as a cleaner, the balance of power shifts and Pink begins to exercise increasing control over her sister.

Matthews commands the stage as the cunning older sister, striking a combative pose as she attacks the “aspirational” TV culture of the middle-classes (“wiv dere Pret-a-Mange free-rangey baguettes an’ flatish whites”), and her social critiques gain a barbed relevance amongst the Sloane Rangers decking out the auditorium. Rolly is a delicate balance of warmth and vulnerability, with Kendrick conveying a wide-eyed, fractured innocence as we witness her descent into full-blown addiction and emotional dependency. 

Rolly and Pink refer to their makeshift digs as a “nest”, and Joanna Scotcher magnifies this impression through her design. An enormous mound of detritus, including filthy mattresses and moth-balled duvets, are piled high and enclosed by a network of steel pipes. Above, a single strip-light fizzes into life, bathing the space in a cold, electric glow. We’re somewhere in London, but the precise location is never specified and this only adds to the sense of dislocation. Meanwhile, Kim Beveridge’s video design neatly captures Pink’s deteriorating mental state through a series of hallucinations and the overarching sense of menace is topped off by Emma Laxton’s churning, industrial soundscape.

However, Pests‘s most distinguishing quality resides in Franzmann’s mastery of language. Rolly and Pink speak through a mixture of cockney phrases, Jamaican patois and childish gobbledegook. This bracing concoction of registers creates a world unto itself. The sisters occupy a sealed-off realm in which an escape into language offers temporary respite from the hostile reality of their lives outside. Comparisons to Philip Ridley are inevitable, but the density of Franzmann’s wordplay reminds me more of reading Anthony Burgess’s A Clockwork Orange. The experience of deciphering this language through a process of osmosis has a similarly heady effect in theatrical terms.

Unfortunately, what begins as an electric shock to the nervous system is reduced to the dramatic equivalent of being bludgeoned over the head with a blunt object, particularly in Franzmann and Morrison’s attempts to ratchet up the intensity by breaking up the action into a series of smaller, more violent episodes by the play’s second half. Ultimately, Pests is a difficult play to love, but I don’t really think it wants to be loved. That’s not why it exists in the first place. Instead, it seizes you by the throat, gets a stranglehold, and punishes you in a language that is wholly its own.

Pests is playing at the Royal Court theatre until 3 May. For more information and tickets, see the Royal Court Theatre website.