When he wasn’t quite 11 years old, my father was awoken in the middle of the night by eight soldiers with fixed bayonets. He and his mother were told to get dressed, but not to pack any of their possessions since “these already are not yours”.

They were put on a flatbed truck and driven to the station in their home town of Lvov. Then my dad was prodded down a hill with a bayonet and forced on to a cattle train. And there he and my grandmother waited, stuffed into an empty carriage with 40 others with nowhere to sit, no toilet but a hole in the floor, and no food.

My father remembers a little girl on the platform playing hopscotch. With her game she tapped out the code: “I am a scout, I take messages.” And that was how news reached my dad’s aunt and she came with a loaf of bread. It was good that she did. When the cattle train left Lvov it travelled for almost three weeks and for days at a time there was nothing to eat. Even before the train reached its destination — reached the bleak wasteland where the ox wagons waited to take them on to their new home — many of its passengers died.

Jews and cattle trucks. It’s the familiar story of the Holocaust. When my mother tells schoolchildren her own story of transportation to concentration camp, she often stops to contrast its shortness with my father’s ordeal.

But the difference between my parents’ experience was not just the length of the train journey. It was that my ten-year-old father was not arrested and starved and imprisoned by the Nazis. The Nazis didn’t reach Lvov until my father was long gone. My father had been sent to Siberia by the Communists. They’d arrested all the men first — and shot many of them in the woods at Katyn — then a couple of days later returned to round up the women and children.

I was thinking of all this yesterday morning, because of the 60th anniversary of the invasion of Poland. My father’s home was in Poland when he left it; now Lvov is in Ukraine, a concrete symbol of what the war did to the Polish. And then I read about Sam Wanamaker.

I’ve always rather liked the late actor and director Sam Wanamaker, and I bet you have, too. He had charm. His daughter Zoë, the actress, is always good value. And, born in America though he was, there was something wonderfully English about his eccentric Globe Theatre project, and something rather moving about the fact that there it is, built at last. So the story that Britain’s security services had a plan to intern him in case of a Soviet attack seems to reveal a policy simultaneously faintly comical and thoroughly objectionable. I have to harden my heart and insist that it wasn’t.

Sam Wanamaker had fled the United States to these shores when he was blacklisted by Hollywood. He was just one who fell victim to the hysteria whipped up by the repulsive Senator Joe McCarthy. It was a lamentable episode. But wronged victim though he was, Wanamaker had been a member of the Communist Party and continued to support communist causes. And for that reason the FBI and the British security services were right to keep an eye on him and others like him.

The first reason for this should hardly need saying, but it does. Communism was a malign doctrine, responsible for murder and oppression on a vast scale. Brought up the son of victims of the Nazis and the Communists, I wasn’t raised to spend my time distinguishing between their crimes, and I don’t. Such distinctions quickly descend into counting bodies, in a macabre calculation of evil. So why should the fellow travellers of fascism be considered pariahs, while those of communism are regarded as liberals who spent too long in the student union coffee bar and became a little overheated, poor dears?

That communism was colossally wrong with evil consequences would not, by itself, justify surveillance of its protagonists. But there is more. We now know that those who believed that the American Communist Party was a conspiracy against the State were correct. McCarthy’s speeches were a web of lies spun together by bluster. He slandered entirely innocent people. But that doesn’t mean there wasn’t a communist plot.

When the Soviet archives were opened, the historian Harvey Klehr brought to light one document after another that proved that the Communist Party had penetrated US government agencies, stolen official papers and tipped off the Kremlin on Soviet citizens who might defect.

This was not marginal activity. The archive shows that US communists helped the Soviet Union to penetrate the Manhattan Project and stole most of America’s first nuclear secrets.

Anyone who wants to learn how this works should read Sam Tanenhaus’s magnificent book An Un-American Life. He tells the story of Whittaker Chambers, the Soviet spy who turned. When Chambers exposed the undoubted guilt of his fellow spy, the establishment member Alger Hiss, it was he, rather than Hiss, whom liberals excoriated. It is remarkable how many, even today, assert that Hiss might be innocent.

In Hollywood the Communists had their own blacklists, taking power in the unions, attacking those who didn’t toe the line, building up their organisation. Some of their activity was admittedly absurd — trying to insert socialism into the plot of Lassie, for instance — but some make the protestations about free speech look strained.

All this communist activity was funded by the Soviet Union, which smuggled in jewels to finance the US network. And in Britain a man called Reuben Falber took delivery of bagloads of cash from the Soviet Embassy. He hid the money in his attic, then channelled it to the Communist Party of Great Britain, of which he was assistant general secretary.

He may have been a nice man, and in many ways a good one, but I am afraid if the security services weren’t keeping one eye on Sam Wanamaker, they wouldn’t have been doing their job.

daniel.finkelstein@thetimes.co.uk

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