Ear to the Ground – Operation Gold and the Top Secret Wire Tapping Tunnel Under East Berlin

British and American agents spent much of 1954 tunnelling under East Berlin to tap into a Soviet phone line linking the Eastern Europe to Moscow.

A preserved segment of a tunnel U.S. agents dug beneath East Berlin. British and American intelligence spent much of 1954 borrowing under the communist side of the city to tap into a Soviet phone line linking Eastern Europe to Moscow. Once the wires were in place, western spies collected tens of thousands of hours of Warsaw Pact military communications.

“CIA director Allen Dulles called it ‘one of the most valuable and daring projects ever undertaken.'”

NSA WHISTLEBLOWER Edward Snowden revealed last week that the U.S. government has been secretly tracking the Internet habits, e-mails and phone calls of millions of Americans. The revelation set off a firestorm of controversy in the United States with media pundits lining up to brand Snowden either a hero or a traitor while Congress has vowed to investigate the legality of the program.

Interestingly enough, not all secret U.S. government surveillance programs have been met with as much hostility from the public. In fact, the discovery in 1956 that Washington had assigned an army of eavesdroppers to actively monitor tens of thousands of phone conversations was widely acclaimed as a victory for democracy. That’s because in this case, the breech occurred in East Germany during the Cold War and targets of the surveillance were the Soviets and their East Bloc allies.

British and American spies operating in West Berlin kicked off the top-secret caper in 1952. The project involved western intelligence operatives tunnelling under the Iron Curtain and physically tapping into a Soviet military phone cable to listen into every phone conversation and telegraph communiqué between Moscow and the East German capital. Before Moscow very publicly announced it had uncovered the scheme, the tap yielded a treasure trove of intelligence data for Washington and London. CIA director Allen Dulles called it “one of the most valuable and daring projects ever undertaken.”

But most astonishingly of all, the Soviets actually knew about the entire operation almost as soon as it was dreamed up.

It was Operation Gold, and it remains one of the most intriguing tales of espionage of the entire Cold War.

Soldiers from the U.S. Army Berlin Command face off against police from the former East Germany. (U.S. Army photo)


Operation Gold, known to the British Secret Intelligence Service (SIS) as Operation Stopwatch, was originally conceived in 1952 by western intelligence to allow NATO to learn as much as it could about Soviet military operations in the East Bloc.

Prior to the advent of orbiting surveillance satellites or the U-2, the west was forced to innovate when spying on its Cold War opponents.

British intelligence had already employed underground phone taps to hook into communist military landlines in Vienna as far back as 1949. Three years later, Washington wanted to run a similar (and larger) operation in Berlin.

The East German capital was an especially inviting target. Recently, the Red Army had transferred most of its communications from over-the-air radio to telephone lines and much of Eastern Europe’s communication infrastructure passed right through Berlin on its way to Moscow.

The objective of the operation was to intercept communist phone conversations.

The Dig

Once identifying the location of the vital phone lines, the Americas handed much of the actual tunnelling to British army engineers who broke ground in February of 1954. The dig site, which was established on the far eastern edge of the American sector, was disguised to look like a radar installation project. The 10-foot-wide sap extended 450 meters (1,400 feet) eastwards into the Soviet zone. In addition to the challenges posed to diggers by the loose sandy ground in the area, underground water deposits caused flooding. Eventually, the walls of the shaft were reinforced and pumps drained the water so that the work crews could reach the target — a thin bundle of phone cables that lay less than three feet below the surface of the ground beside a major roadway.

With the wire tap in place, not much went on in East Berlin that Western intelligence didn’t know about. (Image source: WikiCommons)

Flood of Intel

By May of 1955, British engineers had isolated and tapped into the phone line. Technicians ran a line back to amplifying equipment in the tunnel. Almost immediately, a steady stream of intelligence began flowing into the west. According to the CIA, translators were soon sifting through 40,000 hours of phone conversations and a whopping six million hours of telegraphic communication. Amid that, more than 1,700 intelligence reports were intercepted and more than 400,000 conversations were transcribed.

East German authorities literally stumbled across the operation by accident. (Image source: WikiCommons)


The information pipeline had been up and running for nearly year when in the early hours of April 22, 1956, an East German work crew arrived at the site of the tap, ostensibly for routine repairs. Excessive rains had supposedly flooded the area surrounding the cable and moisture had penetrated the wires causing transmission problems.

Horrified lookouts on the edge of the American sector observed the team digging and ordered an emergency evacuation of the shaft. The workers soon exposed the cable and immediately broke through into the far end of the tunnel.

The following day, authorities in East Berlin announced to the world that they had stumbled across a secret spy tunnel. Moscow loudly proclaimed its outrage and protested the violation.

But, far from being an embarrassment for the west, the entire plot was seen by allies as a feat of skill and ingenuity.

Yet amazingly, the cable repair team’s so-called surprise discovery of the tunnel was in reality a massive ruse orchestrated by the KGB. Soviet intelligence was already well aware of the tunnel’s existence, but went out of its way to suppress the story, even keeping it from the Red Army high command, the East Germans and the Warsaw Pact.

That’s because details of Operation Gold were passed to the KGB by a highly placed mole in the British intelligence community named George Blake.

The 34-year-old spy had worked for the Allies in World War Two only to be later sent to South Korea prior to the 1950 communist invasion. When Seoul fell to the North Koreans, Blake was captured and imprisoned for three years, during which time he secretly converted to Marxism. After his exchange, he rejoined British intelligence and was stationed in Berlin where he immediately began passing to the Soviets. In addition to betraying the identities of as many as 400 western agents to the KGB, Blake also informed Moscow about Operation Gold.

Despite the severity of the leak, the Russians feared that if they exposed the phone tap too soon, London or Washington might investigate and somehow discover Blake’s role as a double agent. Moscow reasoned that any damage caused by NATO eavesdroppers would be offset by the value of information coming out of the west via Blake.

To this day, historians suspect that much of the information gleaned from Operation Gold was solid. In fact, there is little evidence to suggest that the Soviets used the phone line to plant misinformation.

Blake’s Fate

Blake was eventually outed by an East Bloc defector and arrested. A British court sentenced him to 42 years in 1961. He escaped five years later and fled to Moscow. In 1990, he published an autobiography entitled No Other Choice and in 2007 was awarded a medal by Russian president Vladimir Putin. Blake continues to live in Moscow on a government pension. He is 91 years old.

NOTE: Britain’s Role

Although the SIS’ role in Operation Gold was instrumental, Britain was only too happy to allow the Americans to take the full credit for the coup. Supposedly, when the cable breech was discovered on April 22, 1956, London was only days away from hosting a state visit from Soviet premier Nikita Khrushchev. It was decided by London to keep Britain’s role in the operation as quiet as possible to spare the Queen an awkward meeting with the Russian leader. Even Moscow, fully aware of Anglo participation, went along with the charade to avoid any tension during the meet.

10 comments for “Ear to the Ground – Operation Gold and the Top Secret Wire Tapping Tunnel Under East Berlin

  1. 18 June, 2013 at 5:52 pm

    What’s in the other 2nd Northern Line south of the river?

  2. 6 August, 2013 at 2:09 am

    Awesome article.|

  3. Anonymous
    8 December, 2013 at 1:25 pm

    Do not understand how it was kept secret when so many were involved in its construction and subsequent transcribing.
    Apart from Blake, that is

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