1943: The Colossus was built, by Dr Thomas Flowers at The Post Office
Research Laboratories in London, to crack the German Lorenz (SZ42) cipher. It
contained 2400 vacuum tubes for logic and applied a programmable logical
function to a stream of input characters, read from punched tape at a rate of
5000 characters a second. Colossus was used at Bletchley Park during World
War II —as a successor to the unreliable Heath Robinson machines. Although 10
were eventually built, most were destroyed immediately after they had
finished their work to maintain the secrecy of the work.