Cambridge Five – Wikipedia

The Cambridge Spy Ring was a ring of spies in the United Kingdom, which passed information to the Soviet Union during World War II and was active from the 1930s until at least into the early 1950s. None was ever prosecuted for spying. The number and membership of the ring emerged slowly from the 1950s onwards. As far as the general public was concerned, this started with the sudden flight of …

https://en.wikipedia.org/wiki/Cambridge_Five