'The Impossible' navigates post-tsunami sensitivities

Ewan McGregor is casting his mind back to Christmas 2004, and the Indian Ocean tsunami that caused havoc across Southeast Asia. "I remember the news footage, and that feeling of horror about it - that so many people had been lost," he says, sounding almost dazed when we meet in a hotel in London's Mayfair.

Echoing feelings many of us experienced on that tragic day, his bewilderment is understandable: the most destructive tsunami on record killed upwards of 230,000 people across 14 countries, leaving millions more homeless as 30-metre-high waves engulfed coastal areas.

Now, eight years on, comes The Impossible, a film that starkly deals with the tragedy, starring McGregor and Naomi Watts. They play British couple Henry and Maria Bennett, holidaying in Thailand with their three young boys when the wave strikes, sweeping away Maria and their eldest son, Lucas (Tom Holland). Forget about Hollywood disaster movies, though: The Impossible is an altogether different experience - harrowing, authentic, immediate and painful.

"The whole concept of the film was to make people feel the experience of being there," says Spanish director Juan Antonio Bayona, who has traded the supernatural shivers of his 2007 debut The Orphanage for an altogether more tangible horror. "I was not the one who chose the story. The story chose me."

Bayona came to it by way of his producer, who heard a radio interview with a Spanish family who survived the tsunami. Inspired and touched by their miraculous escape, "I realised I had to do the story - and started to work out how to put that on the screen".