Ladies and gentlemen, it’s time to clutch your privately owned pearls, for the shadow chancellor, John McDonnell, has had the audacity to acknowledge – live on TV, no less – that there is a lot to learn from Karl Marx. Judging by the horrified reaction McDonnell’s comments unleashed, you’d think he had ridden into BBC studios on a Soviet tank, shouting “Death to the bourgeoisie!”

It doesn’t end with McDonnell, of course. When Jeremy Corbyn was asked whether he was influenced by Marx’s ideas, he said that “all great economists influence all of our thinking”. And, of course, when Ed Miliband was leader of the Labour party, an intrepid reporter from the Daily Mail went into full reds-under-the-bed mode, by printing the ideas of the Marxist academic Ralph Miliband (Ed’s father) that are already publicly available in books. No word from the Pulitzer prize board yet, but it’s surely only a matter of time.

If these histrionics are anything to go by, the respectable position must be that Marx’s ideas are outdated and dangerous, and that we should all carry on as though they never existed. But if we depart from the juvenile intellectual dead zone that calls itself mainstream political discourse for a moment, we could observe the role his writing has played in upending the political direction of the entire world.

Agree with him or not, his thought has had an unrivalled influence on not just politics, philosophy and economics, but art and media criticism, anthropology, sociology, theology and linguistics. Ignoring the impact of Marx on modern society is like saying Shakespeare has no relevance to English literature, or that biologists should be ashamed of reading Darwin. Only in the facile arena of modern politics would such idiocy be tolerated.

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The fact is that we can’t understand capitalism without considering Marx, and perhaps this is why he was voted the millennium’s most influential thinker as part of a BBC poll in 1999. Marx’s importance comes from the fact that he wasn’t just the first to form a really complete understanding of how capitalism actually works; his analysis gave people the tools they needed to change it. And while the ruling class hasn’t been overthrown, or private property eliminated, plenty of his proposals – just as radical when he wrote them – are common sense today. These include free education, abolition of child labour, a progressive income tax, a national bank, and closing the gap between town and countryside. What should John McDonnell do: swiftly promise to reinstate child labour to prove he’s not a Marxist?

I suppose this is the bit where I point out that Theresa May has just announced that she wants to introduce price controls on energy, price controls being a key part of Soviet economic planning. Ed Miliband suggested the same thing when he was leader of the Labour party, to which David Cameron promptly responded by accusing him of living in a Marxist universe, something the Joseph McCarthy division of the British press was only too keen to echo at the time.

But I’m not going to suggest May is a closet Marxist, because the only thing more stupid than coming to that conclusion would be entering into a kind of political discourse that consists solely of accusing your opponent of being more communist than you are.

Instead, let’s talk about the fact that British wages have been flatlining for a decade – a fact that caused Paul Johnson, director of the Institute of Fiscal Studies, to comment: “I cannot stress how extraordinary and dreadful this is.” Let’s talk about the fact that a rising share of global income is now going to landlords, rather than to wages. Let’s talk about the fact that more than half of British people in poverty are living in working households.

This remarkable imbalance of power between labour and capital is the foundational problem Marx seeks to address in his writing. He suggested the solution was for workers to organise themselves into a class, overthrow their rulers and take control. To that end, it’s not difficult to see why he’s become something of a bete noire in public debate. Political figures and national newspapers are welcome to be scandalised every time his name his mentioned. But Marx was right that capitalism doesn’t work for an awful lot of people. And this inconvenient fact cannot simply be wished away.