Writer/director Ruth Platt’s third feature Martyr’s Lane is a superb piece of work, with a great handle on both tone and atmosphere. While it does have its faults and imperfections, it is a satisfying addition to the ranks of cinematic ghost stories and holds appeal beyond simple jumps and scares. Like all decent horror, it uses the supernatural as an allegory: this is a powerful film about how grief hurts us – and we in turn can begin to hurt others.

Martyr’s Lane follows 10-year-old Leah (Kiera Thompson), who lives in a rural vicarage with her mother and father – a local priest. At night she begins to receive visits from a pale, nameless child with angel wings (Sienna Sayer), who knocks on the outside of her bedroom window.

There is a wonderful subtlety to Platt’s film. This is the form of film horror that I enjoy the best. The film does not rely on extensive visual effects to represent the girl who haunts Leah, nor does it overly rely on the famed “Lewton bus” technique of sudden, jarring surprises. It is the sort of supernatural story that utilises a slow, brooding build. Tension rises slowly, with a growing fear that builds over time. As is often the case, the potential for violence and terror is much more emotionally effective than any actual events that may occur. This is a film about a haunting that actually feels haunting.

Much of its success relies on its two key performances. Kiera Thompson presents a powerfully complex protagonist as Leah, and expresses a good range of emotions and doubts. As her mysterious visitor, Sienna Sayer manages to find the point of balance between being an ordinary child with an underlying malevolence. They are ably supported by the adult cast, including Denise Gough and Steven Cree as Leah’s mother and father, and particularly by Hannah Rae as her older sister Bex. There is a matter-of-fact honesty to Platt’s screenplay, with characters that act believably and feel authentic. This seems particularly true of Bex, who rings remarkably true as an teen sibling: both a mean bully and a supportive carer at the same time.

It is a shame, then, that the film’s climax becomes something of a stereotype, abandoning the queasy uncertainty of earlier scenes for a poorly-judged exercise in glowing lights and raucous sound. The rest of the film feels significantly more measured and thoughtful – and much more satisfying as a result – and it is a shame that so much well-built potential is suddenly squandered. It does not ruin the film, but it does rather dent it.

Ruth Platt is developing something of a reputation as a rock-solid British horror filmmaker, thanks not only to this but also her 2015 feature debut The Lesson. She has become a director well worth keeping an eye on, to see how her craft and creativity develop over future films.