Germaine Greer famously said that women have no idea how much men hate them. Her maxim has a new relevance in the light of this terrifying (and enraging) documentary about the explosion of deepfake porn targeting women: famous women, of course, like Greta Thunberg and Alexandria Ocasio-Cortez who dare to get above themselves, but also private women who are just trying to live their lives and have been hit with this revenge-hate tactic from fantasists, ex-boyfriends, would-be boyfriends, a range of misogynists and incels.

Deepfake porn is booming and making serious money for the porn sites who refuse to take these images down and are under no legal compunction to do so. Last year, the YouTuber who goes by the name Gibi ASMR spoke publicly about experiencing a loathsome attack. Another Body’s heroine is, however, someone else: a woman studying engineering who first alerted Gibi ASMR to her situation because it had also been done to her by the very same man, her face attached with startling realism to porn images, and using her actual name. She herself appears to have been told about it by a male friend, who presumably had to ride out his own embarrassment at thereby admitting to his porn use. To protect her privacy, Another Body gives this woman the pseudonym “Taylor Klein” and actually uses a deepfake image of someone else’s face in the interviews (I had assumed the film-makers would use an AI face, but an actual actor is credited).

With courage, toughness and some digital sleuthing, “Taylor” discovered overwhelming circumstantial evidence as to the identity of the culprit: incredibly, he was in her friend group at college. (“Taylor” is a gamer, incidentally, and there is a chilling suggestion that this man’s deepfakes were revenge for losing to her, or that he had been encouraged by another loser.)

This is a powerful and important documentary, though I have one tiny qualification. Using a deepfake face for “Taylor” is a clever idea in some ways, and more interesting visually than just putting her face in shadow. But it also rather undermines the all-important integrity of reality, which is the film’s moral platform. Perhaps the film could have centred on Gibi, the person happy to speak out publicly. Either way, it is a compelling work.

• Another Body is released on 24 November in UK cinemas.