Country of birth: England
Country of allegiance: Soviet Union
Melita Norwood was a British civil servant with communist leanings whose work at a secret nuclear research facility gave her access to sensitive documents. Although her leanings didn’t alarm many in British intelligence, they caught the attention of the Soviets, who successfully recruited her as a spy in the 1940s.
For the next four decades of the Cold War, Norwood proceeded to pass volumes of state secrets to her Soviet handlers. Although she was detected in the 1960s, inexplicably, British intelligence chose not to act on any of this information.