Operation Silver was a British intelligence operation which ran from 1949 to 1955 that covertly tapped into the landline communications of the Soviet Army headquarters in Vienna. The operation was never discovered and ended only when Austria regained full sovereignty. The British monitoring station was disguised as a shop which sold tweed clothing. In 1951, when the American CIA planned a similar operation in Berlin, the British revealed Operation Silver to the Americans and the two countries then jointly ran Operation Gold.