The Boy Who Would Be King review: Arthurian legend meets London suburbia in Joe Cornish’s latest adventure

Almost eight years have passed since Joe Cornish brought science-fiction to an inner city council estate in his alien-invasion movie Attack the Block. Now the writer-director deftly splices London suburbia and Arthurian legend in The Boy Who Would Be King, the story of a 12-year-old who yanks a big sword out of a bit of concrete on a building site and toddles off in search of an evil witch to stab.

Pitched squarely at an under-served audience too old for kids films and not quite old enough for the increasingly convoluted spaghetti-mess of Marvel franchises, this modern twist on medieval folklore follows Alex (played by Louis Serkis, of the family Serkis) on a noble quest to defeat an ancient evil and her undead army of skeletal ghost warriors.

Alex is an unexceptional school kid turned unlikely hero, who along with his perennially bullied friend and sidekick Bedders must turn bullies into allies and prevent a fiery apocalypse befalling Britain.

Merlin shows up early doors, both to prove that Alex isn’t simply some deluded preteen wielding a dangerous weapon and to provide some much-needed exposition. Rather than the wizened old sorcerer you would expect, he’s a lanky, awkward teenager in an oversized Led Zeppelin t-shirt, whose clumsy attempts to infiltrate Alex’s school disguised as a fellow student provide the film’s funniest moments.

The loose fantasy genre gives Cornish licence to lean heavily on storytelling conceits. When each night evil horsemen emerge from the soil in pursuit of Alex, time freezes and everyone else in the world momentarily disappears, conveniently explaining why Scotland Yard can’t just swoop in and nick everyone, but at the same time allowing for some weighty battle scenes in the abandoned and car-strewn streets of Zone 3, as the kids brandish street signs as makeshift shields and send demons crashing into local bus stops. It’s the same keen mix of the ordinary and the otherworldly that made Attack the Block so compelling.

This time the adventuring is set against the grim backdrop of increasingly pessimistic global affairs, which on one level addresses the sense of helplessness felt by the younger generation in this era of unrelenting political turmoil, but on another addresses a more widely held urge to swing a big sword around and be the most important person in Britain.

The Boy Who Would Be King is a sharply written and unpatronising children’s adventure that espouses the chivalric virtues of empathy and goodwill, without condescending or forgetting to be fun.