Raymond "Jerry" Roberts was part of a group of experts who cracked German High Command's Tunny code at the British listening post. They read Hitler's messages, sometimes before the intended recipients.
He was a German linguist and co-founded with Ralph Tester the Testery section. It broke into the Tunny system which carried the messages of Hitler's top generals and the Fuhrer.
Testery used four times as many encryption wheels as Enigma machine, which carried military communications.
Mr Roberts later revealed he loved reading Hitler's messages, describing them as gold dust. He said: "We were breaking 90% of the German traffic through 1941-45. We worked for three years on Tunny material and were breaking, at a conservative estimate, just under 64,000 top-line messages."