His intelligence was subsequently crucial in guiding Margaret Thatcher in her early contacts with the reformist Mikhail Gorbachev, whose ascent to power helped bring the Cold War to a close.

MOSCOW--Mikhail Gorbachev, who set out to revitalize the Soviet Union but ended up unleashing forces that led to the collapse of communism, the breakup of the state and the end of the Cold War ...

LONDON (AP) — Oleg Gordievsky, a Soviet KGB officer who helped change the course of the Cold War by covertly passing secrets ... In 1984, Gordievsky briefed soon-to-be Soviet leader Mikhail Gorbachev ...