Berlin Tunnel

   Faced with a lack of good human intelligence from the Soviet bloc in the early 1950s, the United States and Great Britain attacked the Soviet target with imaginative technical programs. In Vienna (Operation Silver) in the early 1950s and later in Berlin, the Western allies dug tunnels to tap the Soviet land lines. The Berlin Tunnel (Operation Gold), which was completed in February 1955, projected hundreds of meters into East Berlin and tapped the major military phone lines between Moscow and the Soviet headquarters in East Berlin. The tunnel intercept operators recorded 28 telegraphic circuits and 121 voice circuits continuously.

   The KGB was alerted to the building of the tunnel by George Blake but decided to allow it to operate to protect this key agent from discovery. The KGB may have warned a few of its own communication personnel of the possible threat, but it allowed the Red Army as well as its GRU colleagues to continue to use the contaminated lines. The tunnel was “discovered” after 11 months and 11 days of operations. Western intelligence services benefited tremendously from the “take” from the Berlin Tunnel. According to a report by a CIA officer, more than 440,000 conversations were transcribed, which produced 1,750 classified intelligence reports. Also important was RUMINT (rumor intelligence or gossip) about the leadership of the Soviet Union and East Germany gathered from the talk of Soviet general officers in Berlin with their colleagues and families in Moscow. The tunnel also produced especially sensitive reports on the development of Soviet nuclear weapons and delivery systems.