That truth can be a stranger beast than fiction is a maxim quoted to death with regard to documentaries; but Bart Layton’s punchy take on a tangled and troubling 90s news story really rams the point home. The bizarre decisions these characters make, the ludicrous risks they take and the wilful self-delusion that all or some of them are practising would never survive to the end of a script meeting; everything about this story is unconvincing, except for the fact that it – or some version of it – happened.

A black-stubbled, brown-eyed, twenty-something, French-speaking drifter wouldn’t attempt to pass himself off as a blond, blue-eyed American boy missing for three years. The lost boy’s family wouldn’t accept him and take him in. The police wouldn’t be fooled; certainly not the FBI… Yet Frédéric Bourdin was accepted by the family of Nicholas Barclay, and lived among them, even as the black roots grew into his dyed blond hair.

Layton lets this charismatic monster talk directly to the camera about his side of the scam, a technique that lets us experience his extraordinary persuasiveness, but also reveals his scary absence of compassion. At no point does he betray any awareness that his actions might have been cruel, or caused pain: while deep emotional trauma must – as he claims – lie behind his actions, he relates the whole thing as if it were a daring lark.

The film sometimes errs on the overly playful side: the intermittent comic interludes and macabre closing set piece seem a little vulgar when you recall that we are still talking about a lost and probably murdered child. Still, the story is gripping, and the film leaves enough questions in its wake for fertile post-screening debate.

Selected release from Fri 24 Aug.

The Imposter Official US Trailer 720P