Based on the full ACE design by Alan Turing, the Pilot ACE was one of Britain’s first computers. Designed at the National Physical Laboratory (NPL), it ran it’s first program in May of 1950. Running at a blistering 1 megahertz, it was one of the fastest early computers and despite being a prototype it was extremely useful because of it’s ability to do floating point arithmetic.
With 800 vacuum tubes and mercury delay line memory, instruction time was anywhere between 64 ms to 1024 ms. It was successful enough that a commercial version, the DEUCE, was produced by the English Electric Company. Shut down in 1955, it was donated to the London Science Museum, where it has remained.