Colossus Mark 2

James Pegrum built the Colossus Mark 2:

1944AD 1st June, Bletchley Park, England. The improved Colossus Mark 2 starts working in time for the Normandy Landings.
The Colossus was the world's first electronic digital computer that was at all programmable. It was designed by Tommy Flowers to solve a problem posed by a mathematician, Max Newman. In December 1943 the prototype, Colossus Mark 1, was shown to work. There were ten Colossus computers in use at the end of the second world war.
The computers were used by British code breakers, giving the Allies valuable intelligence, obtained from reading many encrypted high-level telegraphic messages between the German High Command and their army commands.