The idyllic forest scenes are so charming, and the subsequent urban slapstick scenes so hilarious, that it seems a shame that Bong and his British co-writer, Jon Ronson, didn’t cut some of the swearing and the vicious violence. If they had, their frequently witty and twistily plotted film would have been a family adventure to beat The BFG and Pete’s Dragon. That is, it would have been a 21st-Century ET The Extra Terrestrial, except with a bilingual script and a hard-hitting pro-vegetarian message. Like that classic, Okja manages to balance its cartoonish concept and its wild action with characters we can can care about. Even Swinton’s Cruella De Ville-ish villain is humanised: beneath the power suit of a preening CEO, she is a damaged little girl who still practises her signature in her notebook and has braces on her teeth.

But Jong loses control of the film’s tone in its second half. Once the story moves from Seoul to New York, there is a gradual increase in implausibility until, eventually, the anything-goes wackiness overshadows the sombre indictment of industrial meat production. This misjudged zaniness is embodied by Jake Gyllenhaal. Playing a thickly-moustached, squeaky-voiced celebrity vet, he doesn’t seem to know what he’s doing, but for some reason it involves flapping around like a marionette being operated by an inept puppeteer. Okja may be a film about a humungous pig, but Gyllenhaal is the biggest ham in it by far.

Don’t let that put you off, though. A slightly shorter, slightly more disciplined Okja might have been better, but the one Bong has made is still a joy. And it does pose a tricky question to anyone planning to grab a burger after seeing it: if the thought of a CGI animal being turned into sausages is so upsetting, why are we willing to eat real ones?

★★★★☆

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