Yuri Ivanovich Modin was a Russian KGB agent, best known as the KGB controller for the "Cambridge Five" from 1948 to 1951, during which Donald Duart Maclean was said to have passed atomic secrets to the Soviets. In 1951, Modin arranged the defections of Maclean and Guy Burgess. Modin's predecessors in control of the damaging Cambridge spy ring were executed during Stalin's Great Purge. He worked extensively within the KGB’s operations, including disinformation campaigns and active measures.