Just found this:
“Contrary to popular believe, Colossus was not used to break the German Enigma machine. The Enigma was broken by means of an electro-mechanical machine, known as the Bombe, designed by Alan Turing and Gordon Welchman.
Colossus on the other hand, was used to break the Lorenz SZ-40/42. A highly sophisticated teleprinter attachment with no less than twelve complex cipher wheels. It was used by the German High Command for messages at the highest level, for example between Hitler and Field Marshal Rommel in North Africa.”
Life is what happens to you while you're busy making other plans -- John Lennon