Mikhail Gorbachev, former president of the Soviet Union, who ended the cold war and made it possible to dismantle the Berlin Wall, has never been a man of modest ambitions.

When he became Soviet leader 21 years ago he invented perestroika to restructure the ossified edifice of the state and the Communist party, only to see his creaking empire fall apart six years later. For that he is revered internationally and reviled by many of his fellow Russians.