Captain Guy Liddell, the Scotland Hard
analyst who joined MI5 in 1931 and was
appointed director-general of the
counterespionage division in 1940.
Klaus Fuchs, the German-born physicist who
betrayed atomic secrets to the Soviets from
Los Alamos and Harwell and was eventually
compromised by VENONA.Sir David Petrie, the former head of the Delhi
Intelligence Bureau, who was appointed
director-general of the Security Service in
1940.