• Appointed head of GC&CS after WW1 and under his leadership, GC&CS enjoyed great success in the 1920s against foreign diplomatic traffic.

  • Established Sigint relationships with first the French and then the Poles in the 1930s.

  • Planned for the wartime expansion of GC&CS in time for its move to its war station at BP in August 1939. He did so by recruiting ‘Men of the Professor Type’ from British Universities. He persuaded the Treasury to fund the expansion before GC&CS was producing any relevant intelligence.

  • By the Battle of Britain, Ultra was relevant and gave ‘C’ access to the PM.

  • In the early 1940s he established Sigint links with the US and Canada.  

  • After moving to Berkeley St. he had great success in the diplomatic Sigint work. The BRUSA agreement of May 1943 did not cover diplomatic traffic, yet he succeeded in establishing excellent collaboration with the Americans.

  • His character was a key factor in his success. He allowed innovation to flourish and believed that a diverse work force would be effective against Sigint systems used by Britain’s enemies. This is perhaps best exemplified by two of his early recruits: Turing and Welchman.

Image: Alastair Denniston, 1939