Mikhail Gorbachev changed the world, without entirely meaning to. He was a younger, different kind of Soviet leader, who hadn't experienced the brutality of Stalin's regime or fought in World War Two.

He'd visited Western Europe, so he knew that the propaganda about Soviet living standards being higher than in the West was nonsense. And he never forgot the stories his grandfather had told him about being tortured by Stalin's secret police.

Gorbachev realised the Soviet Union had to be changed, but the way he did it ensured it would come crashing down. The Marxist-Leninist system was destroyed, the old Soviet empire broke up and the economy virtually collapsed for several years.

By 1999 Vladimir Putin came to power, determined to rebuild Russia's power, re-instate the power of the old KGB, and force Ukraine, in particular, back into Moscow's orbit. We're still living with the results.

Mikhail Gorbachev questioned the invasion of Ukraine and was a vocal critic of Vladimir Putin. But he was never popular in Russia after 1991 because most people believed the collapse of the old system had been his fault.

Gorbachev had two major policies, glasnost (openness) and perestroika (economic restructuring) - and afterwards, privately, he accepted that he'd introduced them in the wrong order. He loosened the fierce controls on people's lives and freedom of speech before they saw any benefits from capitalism and he thereby created a tsunami of discontent and anger, some of which still lasts to this day.

But it was another decision that really changed the world: the decision not to interfere when the big demonstrations against the communist government of East Germany built up in late 1989.

Gorbachev wouldn't let the East German authorities open fire on the crowds and without force there was no way of stopping the demonstrations. On 9 November 1989, people in the eastern part of the city realised they were free to go through to the West.

Soon the East German state ceased to exist and Germany was reunited. Each of Russia's satellites broke away in a matter of months.

A feeble coup attempt against Gorbachev by the KGB in August 1991 quickly failed, but it weakened his hold on power, and by the end of the year Boris Yeltsin had elbowed him brutally aside.

Soon, large chunks of the old Soviet Union also dropped away — notably Ukraine, the Baltic states and Soviet central Asia — and Russia was left humiliated and diminished.

Gorbachev might have been feted in the West and be awarded the Nobel Peace Prize, but large numbers of Russians have always blamed him for everything that went wrong.

President Biden says Mikhail Gorbachev was a man of great vision, but in fact he didn't have much in the way of vision. He just knew that there was a huge amount wrong with the Soviet Union and tried to do something about it.

His real strength was his charm and decency. I met him various times, starting in 1985 when he first came to Britain, and I followed him round the world, watching the effect he had on others.

"It's such a relief, to find a Russian leader who's a human being," I remember someone saying to me in Belgrade. "China should have a leader like him," a student told me in Tiananmen Square when Gorbachev went to Beijing in May 1989, three weeks before the massacre.

His personal warmth was genuine. Once on his travels I filmed him sitting with his wife Raisa, whom he clearly adored, listening to an orchestra playing Moscow Nights in their honour. They sat hand in hand, quietly singing the words, and the tears poured down his cheeks.

He may have changed the world, but he was a real human being first and foremost.

BBC