Mikhail Gorbachev

 was a moderate Soviet politician who succeeded Konstantin Chernenko as the General Secretary of the Communist Party of the Soviet Union after the latter's death in 1985. His tenure saw the fall of the Berlin Wall on 9 November 1989 and the collapse of the Soviet Union in the early 1990s. (AUDIO: Protect and Survive) During the late 1980s, he instigated reform within the Soviet Union through the policies of "glasnost" and "perestroika". (AUDIO: Thin Ice)

In 1909, Jason Kane referred to Mikhail Popov derisively as "Gorbachev." (AUDIO: Birthright)

Not all Russians were happy with his reforms. On 28 November 1989, Yuri Azarov called him a "weakling [who sat] in Moscow and [watched] the Berlin Wall fall." (COMIC: The Broken Man)

In an alternative timeline created by the Elder Gods in the hope of destroying Earth, Chernenko was succeeded by the militant hardliner Vladimir Kryuchkov rather than Gorbachev. This ultimately led to the outbreak of World War III on 9 November 1989 between the Soviet Union on the one hand and the United States and its allies including the United Kingdom on the other hand. Given that nuclear weapons were used by both sides, hundreds of millions of people were killed in the conflict. This timeline was ultimately negated by the Seventh Doctor. (AUDIO: Protect and Survive)