9 January 1961

British authorities announce they have uncovered the Soviet Portland Spy Ring in London.

The Soviet Portland Spy Ring, also known as the Portland Spy Case, was a Cold War espionage incident that took place in the 1960s. It involved a group of Soviet spies operating in London who were arrested by British authorities in 1961. The members of the spy ring were passing classified information to the Soviet Union, including details about British naval technology.

The core members of the Soviet Portland Spy Ring were Harry Houghton, a British Navy clerk; Ethel Gee, his mistress; and Gordon Lonsdale, a Canadian businessman who was actually a Soviet intelligence officer using a stolen Canadian identity. Houghton and Gee worked at the Underwater Detection Establishment (UDE) in Portland, England, where they had access to sensitive information related to underwater acoustics and naval technology.

The espionage activities were exposed when a British intelligence officer, Michael Goleniewski, defected to the West and provided information about the Soviet agents. The information led to the arrest of the members of the spy ring in January 1961.

The Soviet Portland Spy Ring case highlighted the extent of Soviet intelligence operations in the West during the Cold War and underscored the importance of counterintelligence efforts by Western countries. The individuals involved were prosecuted, and the incident strained diplomatic relations between the United Kingdom and the Soviet Union.