The human camera.

Stephen Wiltshire is an artist with autism, the world's most famous 'savant'. He is able to look at a building and sketch it from memory in minute detail, perfectly. This fascinating and informative programme looks back over his younger life and charts his progress from being a mute child with a nervous twitch to a confident young man who travels the world alone, with an art gallery devoted to his work. Despite having already achieved so much, Stephen here sets himself a new challenge to produce a panoramic drawing of the entire city of London after viewing it from a helicopter for just 15 minutes. The results are extraordinary.