Professor Brailsford rounds up the whole Colossus affair, and explains how Turing actually played a small but significant part in Bill Tutte's work. Colossus Playlist: Enigma Playlist: What Happens When I Press a Key?: Choosing a Password: This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: Computerphile is a sister project to Brady Haran's Numberphile. More at