Sometimes cinema is at its most potent and engrossing when it’s stripped down to the essentials. Playground, the accomplished, uncomfortably powerful first feature from the Belgian writer-director Laura Wandel, is a lean 72 minutes in length, with no score and a lithe, instinctive, handheld camera that rarely leaves the face of seven-year-old Nora (Maya Vanderbeque, superb). It is piercingly insightful without ever labouring the point.

The film Nora’s well-meaning attempt to intervene when she sees her older brother Abel (Günter Duret) targeted, exploring the way that bullying spreads like a stain through a primary and middle school community; how the taint of victimhood can override the bonds of friendship and family; and how doing the right thing can backfire catastrophically.

Playground’s French title, Un monde, translates as “a world”, and the school is just that: the squat, blocky buildings and treacherous strip of asphalt are a hostile and inescapable environment. There is no respite – either for the audience or for the kids who find themselves outcasts in the semi-feral pack dynamic of childhood.

Frédéric Noirhomme’s camera is virtually a character in the story. It hovers at children’s eye level, nervy in an unforgiving bluish, bruised colour palette, only occasionally allowing an adult to slip fully into focus. A sympathetic teacher (Laura Verlinden) is one; Nora and Abel’s father and, we assume, main carer (Karim Leklou) is another. But equally impressive is the sound: with the camera locked on Nora’s tearful saucer eyes, much of the tension is created, vividly, outside the frame. It’s a remarkable achievement.