In August 1945 Soviet intelligence officer Konstantin Volkov tried to defect to the UK, offering the names of all Soviet agents working inside British intelligence. Philby received the memo on Volkov's offer and alerted the Soviets, so they could arrest him. In 1946, SIS absorbed the "rump" remnant of the Special Operations Executive (SOE), dispersing the latter's personnel and equipment between its operational divisions or "controllerates" and new Directorates for Training and Development and for War Planning. The 1921 arrangement was streamlined with the geographical, operational units redesignated "Production Sections", sorted regionally under Controllers, all under a Director of Production. The Circulating Sections were renamed "Requirements Sections" and placed under a Directorate of Requirements. SIS operations against the USSR were extensively compromised by the presence of an agent working for the Soviet Union, Harold Adrian Russell "Kim" Philby, in the post-war Counter-Espionage Section, R5. SIS suffered further embarrassment when it turned out that an officer involved in both the Vienna and Berlin tunnel operations had been turned as a Soviet agent during internment by the Chinese during the Korean War. This agent, George Blake, returned from his internment to be treated as something of a hero by his contemporaries in "the office". His security authorisation was restored, and in 1953 he was posted to the Vienna Station where the original Vienna tunnels had been running for years. After compromising these to his Soviet controllers, he was subsequently assigned to the British team involved on Operation Gold, the Berlin tunnel, and which was, consequently, blown from the outset. In 1956, SIS Director John Alexander Sinclair had to resign after the botched affair of the death of Lionel Crabb. SIS activities included a range of covert political actions, including the overthrow of Mohammed Mossadeq in Iran in the 1953 Iranian coup d'état (in collaboration with the US Central Intelligence Agency). Despite earlier Soviet penetration, SIS began to recover as a result of improved vetting and security, and a series of successful penetrations. From 1958, SIS had three moles in the Polish UB, the most successful of which was codenamed NODDY. The CIA described the information SIS received from these Poles as "some of the most valuable intelligence ever collected", and rewarded SIS with $20 million to expand their Polish operation. In 1961 Polish defector Michael Goleniewski exposed George Blake as a Soviet agent. Blake was identified, arrested, tried for espionage and sent to prison.