The red carpet led all the way to The Road at the Venice film festival last night, as the dignitaries and their glamorous guests were herded in for a foretaste of the apocalypse. Afterwards they presumably went out for dinner.

Based on the bestselling novel by Cormac McCarthy, The Road follows the voyage of a starving father and son through a ruined America of the near-future. Yet, the film suggests that this world may not be far away. Its bleak, blighted landscapes were shot at real locations across the US.

"We took a tour of the post-apocalyptic sights of America," explained director John Hillcoat. "The poor cast and crew were dragged through the winter of Pittsburgh, to Mount St. Helens, to New Orleans. We went to strip mines in Pennsylvania and to abandoned highways. We saw the poverty and the homelessness of today."

Hillcoat's film stars Viggo Mortensen as the unnamed father and newcomer Kodi Smit-McPhee as his son. Charlize Theron appears in flashbacks as the anguished wife who finds herself unable to stay the course.

McCarthy's tale has already been seized on by environmental campaigners as a warning of things to come. Yet, Mortensen was keen to stress that it is, at heart, a love story.

"It is about something everyone can understand and relate to: what will happen to my child if I'm not around to look after him or her?" he said. "Before we started filming I was lucky enough to speak to Cormac McCarthy on the phone. I meant to ask him all these questions about the book. But he ended up speaking about his son and I spoke about mine. Afterwards, I realised that was all I needed to know."