John Cusack’s mobile phone battery dies just as a mysterious electronic pulse turns everyone with a working one into mad killers.

Escaping the mayhem, he hooks up with fellow survivors Samuel L Jackson and Isabelle Fuhrman and leads them on a cross-country trek towards his old home, picking up an impressive arsenal of weapons en route. But staying alive in a world overrun by rabid ‘phoners’ proves a perilous business.

There’s something genuinely unnerving about this scenario, but the movie fails to make the most of it, despite being co-written by Stephen King from his bestseller.

Cusack and his companions adjust too quickly to the story’s cataclysmic events and they pick up the rules of the infected people’s evolving behaviour – first flocking like birds and then developing a hive mind – with implausible alacrity.

However, the film’s opening scene and ambiguous ending deliver a powerful charge, while the stuff in between will confirm the prejudices of anyone who reckons that mobiles are – in the words of Stacy Keach’s beleaguered headmaster – ‘the devil’s intercom’.