The 20th century was a ‘good one’ for tyrants. There were certainly enough of them who we’d like to forget: Joseph Stalin and his Communist cronies, Adolf Hitler and the Nazi thugs, Pol Pot and the Khmer Rouge in Cambodia, Idi Amin in Uganda . . . et al.

All of them were responsible for the most awful human rights abuses, but particularly the use of extrajudicial and arbitrary killings on a large, even massive scale.

Of course there have been dictatorships in many countries, and some cling to power to this very day. But do they compare with the infamous individuals listed earlier? Surely the answer has to be not quite.

I’ve lived in two countries that were either under a dictatorship (Peru in the early 70s) or had recently come out of one (the Philippines after the Marcos regime). And I’ve had occasion, through my work in international agricultural research, to have visited many countries with less than savoury governments.

But as I read Martin Sixsmith’s recent book about Russia (first published in 2011 as a follow on from a BBC radio series), I did find myself wondering whether, in fact, there are degrees of tyranny, and if Josef Stalin was the biggest tyrant of them all.

Sixsmith’s book of about 550 pages, presents a 1000-year chronicle of Russian history, from its Viking origins to the present. But it’s the discussion of the 1917 revolution and the coming to power of the Bolsheviks, and its aftermath when Stalin came to power that is most compelling.

It is clear – just from the account of the methods Stalin (and his subordinates) used to control the Russian population, and conquered territories, as well as the statistics of the numbers of people summarily executed or forgotten in the gulags – that made me ponder the question about degrees of tyranny. Stalin was truly a monster. But was he worse than Hitler, for example? And is it correct even to ask the question?

Tyranny – even at a local small scale – is an abomination, a blight on society. Having now finished Sixsmith’s very readable account of Russian history, I’m left reeling at the scale of Stalin’s crimes – at home and abroad, actions carried out in the name of and supposedly in support of the proletariat.