aug 22, 1955 - Sigint Affair- Katie Q

Description:

The Sigint Affair, or “Operation Gold” in the United States and “Operation Stopwatch” in the United Kingdom, was one of the most strategic and well executed intelligence operations of the Cold War. It was executed by joint forces of the United Kingdom and the United States. In the 1950s the CIA and MI6 managed to tap into Soviet communication lines through Berlin. Their goal was to intercept information coming through, interpret it, and act upon it. This provided the United Kingdom and the United States with the major plans the Soviets came up with. In order to execute this operation, they had to construct a tunnel from the American sector of West Berlin into the Soviets land, the tunnel specifically targeted the key communication cables buried beneath the city. The construction of the tunnel used highly advanced technology in engineering, which had to be carried out in secrecy. Once the tunnel had reached the communication lines, technicians carefully installed recording equipment to intercept telephone calls and telex messages that passed through the lines. The information was then transmitted back to the Western sector where it would be translated and studied. The information gave up military developments, technological advancements and political decisions. Unfortunately the information didn't last forever, in 1956 the Soviets found the tunnel. Allegedly the tunnel was found because of a double agent, George Blake, who supposedly worked with British intelligence and the Soviets.

Works Cited
“US Signals Intelligence in the Cold War.” Wikipedia, Wikimedia Foundation, 13 Feb. 2026,
en.wikipedia.org/wiki/US_signals_intelligence_in_the_Cold_War.

de Jong, B. Intelligence and the Cold War, 2014,
pure.uva.nl/ws/files/2469780/147596_Ben_de_Jong_Intelligence_and_the_Cold_War_versie_metis.pdf.

“Obituary: George Blake.” BBC News, BBC, 26 Dec. 2020, www.bbc.com/news/uk-25675566.
“George Blake.” Wikipedia, Wikimedia Foundation, 28 Jan. 2026,
en.wikipedia.org/wiki/George_Blake.

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