The Queen has posthumously pardoned Alan Turing nearly 60 years after his death in 1954. He was instrumental to the breaking of codes used by Germany in the 2nd World War (including Enigma) and his ideas went on to be used in many fields of cryptography and computing and are in use even today. While his work at Bletchley Park even today is not fully known, official papers released in 2012 have shown he was more key to the work than most people had previously known. See http://www.bbc.co.uk/news/technology-25495315 for more information.