Yuri Modin (1922- present) was the KGB controller for the "Cambridge Five" from 1944 to 1955, during which period Donald 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.
Modin said of Kim Philby in 1994 that
"He never revealed his true self. Neither the British, nor the women he lived with, nor ourselves [the KGB] ever managed to pierce the armour of mystery that clad him. His great achievement in espionage was his life's work, and it fully occupied him until the day he died. But in the end I suspect that Philby made a mockery of everyone, particularly ourselves."