ou know what the ‘acceptable loss’ of your business is?” a social worker asks a teenager caught in Britain’s brutal “county lines” drug-trafficking business: “You.” That’s a message that rings loud and clear through this impassioned debut feature from writer-director Henry Blake, an alarming yet compassionate portrait of a headline-grabbing scandal that combines the warm artistry of a coming-of-age picture with the cold, hard truths of a public information film. Conrad Khan is Tyler, a disconsolate and somewhat hesitant 14-year-old whose mum, Toni (Ashley Madekwe), seems caught in a cycle of emotional and financial instability. After being bullied by older boys at a local cafe, Tyler thinks he’s found a potential protector in the shape of the enigmatic Simon. Brilliantly played by the versatile Harris Dickinson (unrecognisable from his breakthrough role in Eliza Hittman’s Beach Rats), Simon initially has the air of a tougher older brother, taking Tyler for a spin in his car and teaching him that it’s his duty to “be the man of the house” – to take care of business at home. Soon, Tyler is “running errands” for Simon, profitable but perilous work involving packages and train journeys, sold with empty promises of safety. Gradually, it begins to dawn on Tyler that, rather than finding his place in the world, he’s actually entered into a devil’s pact that will obliterate his identity and his sense of self. In this brutally unforgiving war zone (Blake significantly cites Elem Klimov’s Come and See as a tonal touchstone), he is no longer a person but a human shield – useful yet expendable. Having spent more than a decade as a youth worker, Blake has witnessed the harsh realities of child exploitation in the drugs trade, an industry that the National Crime Agency now estimates involves more than 10,000 vulnerable children. Like Ken Loach’s 1966 BBC TV play Cathy Come Home, which prompted parliamentary discussion of homelessness and unemployment, Blake’s film feels like an alarm bell, calling urgent attention to a contemporary crisis. Yet the traumatising realities of its modern-slavery message wouldn’t strike such a chord were County Lines not blessed with a level of cinematic poetry that both leavens and amplifies its plaintive themes. Working closely with cinematographer Sverre Sørdal, Blake leads us into the increasingly crepuscular world of Tyler’s experience, torn between childhood and adulthood (shades of Shola Amoo’s The Last Tree), inadvertently endangering the very family he’s convinced himself he must save. For all the vérité grit of the story, there’s an expressionist edge to the visuals, a quality that is amplified as Tyler’s life becomes ever more fractured and fragile. A nuanced central performance by Khan in his first starring role personalises wider issues, although Blake is at pains to remind us that Tyler is just the next in a long line of nameless victims. During the course of his story we see secondary characters at different points in the same narrative, whether their paths are simply crossing at a train station or clashing during horribly violent initiation rituals. Whatever the end-point ofTyler’s own journey, our ultimate focus is not on him, but on the wider web from which he may or may not escape. The result may prove too downbeat for some audiences, particularly in its unflinching depiction of extreme violence. But a mournfully ambient and somewhat ethereal score by James Pickering helps elevate this above mere social realism, finding unexpected shards of beauty in even the most dismal circumstances. County Lines is in cinemas and on digital platforms