There are no prizes for guessing the twist at the end of this claustrophobic two-hander set entirely in a field in Gloucestershire. It starts with a promising premise for a low-budget psychological thriller, and there are solid performances from its two actors, but the film never quite generates enough genuine emotion or moments of intrigue to keep it interesting.

Dave, played by Joseph Millson, is a middle-aged man who lives in a caravan in a field in the middle of farmland and keeps a gun in the kitchen cupboard. Millson’s physical presence does a lot to create a sense of foreboding at the start of the film – all fear and self-loathing, coiled with barely repressed rage. Dave has isolated himself from the world, but then a young woman (Natalie Spence), claiming to be a YouTuber, stomps into his field brandishing a camera.

We never find out her name, but from this YouTuber we learn that Dave’s climate-activist daughter has been murdered, and that Dave is the prime suspect. The police do not have enough evidence to charge him, but he’s been vilified in the media. What’s his side of the story, the woman asks Dave?

Things heat up from here. Dave is a far-right conspiracist, with theories on everything from Covid to dinosaurs (“they’re a myth!”). He tells the YouTuber that the order to kill his daughter came from the top of government. As the YouTuber, Spence does the best she can with a limited material, at first earnest in her insistence that she wants to know the truth. But there is something a bit rehearsed about her lines; is she who she says she is? The script and direction can’t manage the high-wire act, and whether you are wrong-footed or not, the twist ending feels a bit silly.

• Empire of Lies is in UK cinemas and on digital platforms from 27 March.