In this remarkable film, Romanian director Cristian Mungiu does something daring: he critiques the implementation of his own progressive values, challenging just how tolerant liberal societies really are. In recognition, the filmmaker was rewarded with his second Palme d’Or (his first was for 2007’s abortion drama 4 Months, 3 Weeks And 2 Days). Inspired by real events, Fjord introduces us to the Gheorghius, a conservative Christian clan consisting of mother Lisbet (Renate Reinsve), father Mihai (Sebastian Stan) and their five children. The family arrive in a remote Norwegian village at the outset after leaving Romania: for the Norwegian Lisbet, it’s a return home.

Although they are friendly in their own reserved way and make themselves useful to their community, their values do not completely align with those of the locals. Their disciplinarian approach to child-rearing raises eyebrows, and rumours of abuse rapidly reach the ear of child services, who pay the family a visit and are all too eager to take the kids away. It’s an uncomfortable watch, and yet feels absolutely essential. Fjord shows how state overreach and rushes to judgement can lead to religious persecution and alienation, with the family driven into the arms of unsavoury types when they become the centre of a social media storm.

There’s nuance in the portrayal of the family’s neighbours, but those working in child protection come in for perhaps too much of a kicking, with the most hissable depiction of a social worker since Hunt For The Wilderpeople, in the shape of Ellen Dorrit Petersen’s pitiless Gunda. With so much at stake and plenty to say, Fjord wears its epic length remarkably well. The lack of empathy creates a real chill in the air, with Mungiu’s austere, unshowy style presenting his case with compelling severity.

Fjord is screened at BFI London Film Festival, Saturday 17 & Sunday 18 October; on general release from Friday 13 November.