'I was born on 31 January 1979 - a Wednesday. I know it was a Wednesday, because the date is blue in my mind and Wednesdays are always blue, like the number nine or the sound of loud voices arguing.' Like the character Hoffman portrayed, he can perform extraordinary maths in his head, sees numbers as shapes, colours, textures and motions, and can learn to speak a language fluently from scratch in three days. He also has a compulsive need for order and routine. He eats exactly 45 grams of porridge for breakfast and cannot leave the house without counting the number of items of clothing he's wearing. If he gets stressed or unhappy he closes his eyes and counts. But in some ways Daniel is not all like the Rain Man. He is virtually unique amongst people who have severe autisitic disorders in being capable of living a fully-functioning, independent life. It is this incredible self-awareness and ability to communicate what it feels like to live in a totally extraordinary way that makes BORN ON A BLUE DAY so powerful.

Daniel Tammet has been working with scientists to understand the implications of his condition for neuroscience and our understanding of consciousness. He also runs a web-based diagnostic site for people with autism and lives in Kent with his partner.