Flood London

In scenes that may no longer be dismissed as far-fetched, a new film is to chart what would happen if the Thames Barrier was overwhelmed.

The movie, based on a book by Richard Doyle, imagines how London would look if it was deluged by a surge of water.

Flood, which features Robert Carlyle, was shot over 11 weeks last year. The author has said he believes there is a real threat to the capital. He has called for the government to take "its head out of the sand".

Guernsey-born Doyle, who now lives on Dartmoor, wrote the book in 2003 after spending two-and-a-half years researching the issue. Writing on his website Doyle says he came up with the idea for the book after reading an article on global warming.

"[It was] one of those terrifying pieces about more extreme weather, rising sea levels and frequent violent storms. Suddenly I remembered the Thames Barrier. I wondered how it would cope. I started to look into some of the details. Barrier height, tidal reports and so forth. The more I looked, the more concerned I became."