It’s a tense, atmospheric piece of film-making but it made me profoundly uncomfortable – and not, I should add, in a good way. There’s a prurience in how the murders are filmed – the camera hungrily scouring the distorted faces of dying women – that borders on dehumanising.

Abbasi has made an Iranian noir which, even though it dares to poke around the spiritual capital of Iran with its largest mosque in the world, isn’t an assault on the Iranian government per se, but a crime thriller which shows how far fundamentalist morality can be twisted and how banal the face of evil really is.

Holy Spider shines a light into the murky corners of a society that emboldens its aggressors. In that sense, the film is essential viewing. Even if it is completely devastating.