And just to add: Peter Hitchens was not supporting Stalin when he spoke of the importance of our wartime alliance with the Soviet Union. And my understanding is that a great many Russians themselves also suffered under his rule.
Instead I think he was acknowledging that without the courage and determination of the Russian people to stand up to Hitler’s Nazis, Germany would not have been defeated in 1945 and a great many more lives would have been lost.
I quote again from the film I posted:
“No country, no people suffered so terribly in the war as the Soviet Union. Nowhere else are the memories of war so alive today  and so profound. The German invasion brought about a catastrophe which it seemed at first no nation could survive. In the siege of Leningrad [St Petersburg] alone which lasted for over two years more human beings died than the total war dead of Britain and the United States combined. Yet it was here that Hitler was broken. The Russian people faced the possibility that they might perish and overcame it.”