Matthew Holness’ debut is a disquieting character study anchored by a remarkable performance by Sean Harris. As Philip, Harris is something of a shellshocked stray cat, lumbering around like Frankenstein’s monster clinging to a bulging leather satchel which contains…well that would be spoiling it. Possum is a British horror movie in the kitchen sink-gothic mould. Think Lynne Ramsay’s Ratcatcher, Cronenberg’s Spider or, more loosely, Denis Villenueve’s Enemy. The thing that connects all these films is the way they’re told. You always feel like you’re only being given fragments of the complete picture – it’s film language as damaged psyche.

You’re never quite sure if Philip is a character to fear or feel sympathy for. There’s a violent past, a missing boy and a big secret that, if only should it be revealed, will surely tie everything together. And that’s where Holness slips up. The film works best as an elliptical urban nightmare, with excellent atmosphere that soaks through to your bones like damp clothing. So when Holness shows his hand in the final ten minutes, explicitly solidifying the plot the rest of the film has worked so hard to submerge, it feels wholly unnecessary. It doesn’t damage the film entirely though. Everything preceding the ending works wonders, successfully establishing and exploring a hostile 70s Britain with a handful of genuinely unnerving scares and images. Not one for the squeamish.