The Berlin Tunnel

From Vienna to Berlin

According to the CIA’s internal history, in 1951 the British told the Agency that for some years they had been tapping Soviet cables in Vienna through a system of tunnels, and offered to share the results. By May 1953 the idea of a Berlin tunnel had taken definite shape.¹

The Director of the CIA approved the terms of reference in December 1953, and conferences in late 1953 and early 1954 divided the tasks between the Americans and the British. The CIA website says Allen Dulles approved the operation in January 1954.^1,2

Construction

The cover was a compound in West Berlin posing as a US Air Force radar site and warehouse. The tunnel ran under Altglienicke in East Berlin.²

The vertical shaft was begun in late August 1954. The tunnel, 1,476 feet (about 450 m) long, was completed on 28 February 1955, and the tap chamber was built between 10 and 28 March 1955. The whole project cost $6.7 million.¹

The three cables were tapped on 11 May, 21 May and 2 August 1955. The taps were installed by British technicians.^1,2

What was recorded

Some 50,000 reels of magnetic tape were used. In London, with a staff that peaked at 317, 368,000 conversations were fully transcribed from the Soviet recordings; in Washington, with 350 staff, the Soviet and German teletype recordings were transcribed.¹

Processing of the backlog continued until 30 September 1958 and produced 1,750 reports and 90,000 translated messages and conversations.¹

George Blake

George Blake was an MI6 officer and a Soviet agent. The CIA history records that the Soviets recruited him in 1952, while he was a prisoner in North Korea, and that by his own account he told his Soviet contact about the planned tunnel in late 1953, when the decision on its location was made.¹

According to the Foreign Office historian Gill Bennett, Blake betrayed many agents, including a network in East Germany, and told the Soviets about the Anglo-American listening tunnel. In May 1961 he was sentenced to 42 years in prison; on 22 October 1966 he escaped from Wormwood Scrubs and made his way through East Germany to Moscow.⁴

The author of the CIA history states that there is no evidence that the Soviets fed deception material through the tunnel, and that we will probably never know the exact rationale behind their moves. A reviewer from the CIA History Staff, discussing Steve Vogel’s book (2019), adds that the final word on this may not yet have been written.^1,5

April 1956: the ‘discovery’

Soviet and East German crews, tracing cable faults after flooding, dug up the cable and at about 02.00 on 22 April 1956 came upon the tap chamber; the wires were cut at 15.35. An appendix to the CIA history, dated August 1956, judged the discovery to be accidental.¹

The Soviet media presented the tunnel as an outrage, while in the West the reaction was largely favourable. The CIA history calls it the most highly publicised peacetime espionage enterprise before the U-2 incident.¹

Names

The CIA’s internal history uses the project codename PBJOINTLY, and REGAL for the system that disseminated the results. CIA publications on cia.gov speak of Operation GOLD.^1,2

According to media and secondary accounts · not confirmed by official sourcesAccording to secondary accounts (including David Stafford’s book Spies Beneath Berlin), the British SIS called the undertaking STOPWATCH.⁶