It doesn’t take long for the other passengers to figure out what he’s done, sealing their doom by exposing them all to this toxin. On the ground, the police are alerted to his bioterrorism after he releases a video online promising to attack an aircraft.

“This is where it all ends,” he declares. Led by Sergeant Koo ( Parasite star Song Kang-ho), the cops soon discover his apartment and his master plan.

While its 147-minute running time is too long, Emergency Declaration does have a Hollywood blockbuster quality to its set pieces.

A scene where the pilot collapses and the plane begins to plummet towards the ocean is brilliantly shot, with several luckless unbuckled passengers thrown around the economy cabin like rag dolls as the aircraft spins out of control.

After the plane is refused permission to land in American airspace, the US authorities dubbing it a “biochemical missile”, the aircraft is forced to turn around, a plot point that really does the film no favours.

On board, Koo’s wife is one of the endangered passengers, while a father (Lee Byung-hun) travelling with his child, who has eczema, has his own inner demons to face. But neither sub-plot adds much.

The film also suffers from imbuing the law enforcers with a Keystone Cops quality that doesn’t help ratchet up the tension.

Im Si-wan is very watchable as the young terrorist – just the right amount of weird. But there isn’t enough of him in a film that comes in for a very bumpy landing.

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