The man who draws from memory

Can anyone remember the program on T.V not long ago about a young man I think he had autism, that could draw from memory.
They took him up in a helicopter and he drew London on a large frieze
I was telling my friend about him and she said she would have loved to have seen it.
Her sister is autistic and she is understandably interested in anything to do with it.
Any info please.

 

Stephen Wiltshire. I just googled "man who draws from memory" and it came up and there is a you tube thing there.

 

That's it, I remember his name now.
I'll pass it on .
Many thanks.