The pop-up theatre Found111 stages the intimate staging of Simon Evans’s revival of Bug – Tracy Letts’s take on the rise of technology and conspiracy theories, making it all the more timely for an audience whose lives are governed by technology.

Kate Fleetwood provides a compelling characterisation as Agnes. A washed-out, drug-dependent, frail mid-forties woman, she cowers in the seedy motel room she calls home, out of fear that her abusive ex-husband (Gosh, played with convincing aggressiveness by Alec Newman) might enter her room at any moment. This is a brave performance by Fleetwood; the fact that she is already on stage as the audience enter the small space reduce all elements of theatricality. It feels more like reality TV, because we are in the same motel room as the actors. Ben Stones’s set is cleverly composed so that there is no end of the stage separating their imagined world from our real one, making for compelling viewing as the struggles and urges of the characters are showcased right before us.

Fleetwood’s Agnes is a breathtaking figure: the looseness and vulnerability of her frame are the strongest aspects of her performance. We sympathise with the baggage she is carrying from her previous marriage, as well as her missing son, Lloyd, and her dependence on the alcohol and drugs scattered messily around the room to mask the pain she is plagued with.

The drama of the piece is ignited with James Norton’s entrance as Peter, a mysterious and reserved figure who we are immediately convinced is hiding something, but only admits a comedic remark: “I’m not an axe murderer.” This unusual and peculiar relationship is sparked after Agnes allows him to spend the night, learning he was once a soldier but is now homeless, living anywhere and nowhere at once. Awaking in the night to bed bug bites, the paranoia of the bugs begins – whether they exist, or are merely imagined.

Norton’s portrayal is a memorable one. He commits totally to both the psychotic obsessions of the character, reminiscent of his portrayal of Tommy Lee Royce in Happy Valley, and the physical roguishness of an ex-serviceman. Most impressive, or rather macabre, is the revolting scene in which he pulls his tooth out, convinced that the US government – after he had returned from a tour in the Gulf War – had implanted a bug inside him as part of an experiment. His large stature enables him to ramble around the claustrophobic space powerfully, dominating the room and careering off on tangents about a world in which “no-one is safe nowadays”.

In a well-rounded production that sees all elements of stagecraft used powerfully, Edward Lewis’s soundboard is utilised particularly well. The mixture of helicopter noises, dog barks and footsteps creates an eerie suspense of things that certainly go bump in the night. What this play and the space at Found111 do so well, is that both infiltrate the audience’s subconscious fears – be it our privacy and safety, or perhaps our fear of insects. Collectively, these gradually build up palpable tension that becomes as contagious as the incessant fly-swatting of the actors. Crawling sensations on the backs of necks grow as the stage becomes overcome with the buzzing sensation of insects.

Overall, this production is certainly a novel experience for many of the audience, many of whom I expect had never visited the unique and trendy studio at Charing Cross Road. No longer are we onlookers, but instead we become voyeurs peering into the troubled and damaged lives of these vulnerable characters. At times it feels as if the characterisations we are witnessing are almost too naturalistic or real – perhaps this is testament to the thoughtful characterisations of the ensemble cast. The close proximity of actor and audience certainly invade personal space, but enable complete focus as the events unravel. As the bugs get bigger and the itches grow in frequency, the audience too begin to feel uneasy.

The highlight of the piece is Norton and Fleetwood’s dynamic duo: two mesmerising personas that ultimately decide to sacrifice themselves, convinced they have “made” the bugs that crawled and nestled under their skin through the night they slept together. Such is the strength of Letts’s writing, that the conspiracies and cults such as this one posed are utterly terrifying.

Bug really got under my skin.

Bug is playing at Found111 until 7 May. For more information and tickets, see the Found111 website. Photo: Simon Annand