Two 70-year-old papers by Alan Turing on the theory of code breaking have been released by the government’s communications headquarters, GCHQ.
It is believed Turing wrote the papers while at Bletchley Park working on breaking German Enigma codes.
A GCHQ mathematician said the fact that the contents had been restricted “shows what a tremendous importance it has in the foundations of our subject”.
It comes amid celebrations to mark the centenary of Turing’s birth.
The two papers are now available to view at the National Archives at Kew, west London.
GCHQ was able to approximately date the papers because in one example Turing had made reference to Hitler’s age.