Floods, warming, resource wars, meteor strike, man-made black hole, nuclear winter, terrorism, novel virus, nanobot invasion, super-eruption. These are the ways the world ends; or, at least, the bit of it we call western civilisation. Our comfort zone is fragile, beleaguered. The sofa, the laptop and the TV hang above an abyss. We must do something — take off our shoes at airports, wash our hands, recycle, send up orbiting banks of nukes to take out nearby asteroids, drive electric, buy canned food, install more CCTV cameras, anything. Or must we?

End-of-the-world stories are commonplace in every era. Once they involved the wrath of the gods; now they are disseminated by experts, usually scientists. Now, too, they are political. In democracies, politicians are obliged to address the anxieties of the people. And really big anxieties demand really big action.

We should, says the historian Richard Overy, “calm down”. Overy has written a book about democracies and the apocalypse. It’s called The Morbid Age: Britain Between the Wars, so it’s not exactly about our own time, but the last word in the book is “now”, and the parallels are unavoidable. In the 1920s and 1930s, they worried about a future war that would end western civilisation, about the genetic decline of the human species, about the fatal effects of “gangster capitalism” and about the Freudian and Dar­winian evidence of human powerlessness before our biological and psychic inheritance. Then, too, democratic politicians felt that they had to react, the people wanted their anxieties soothed. Were they wrong? Are we?

Overy, 61, is a mighty figure, one of the great historians of the second world war, and, first, this radical book should be placed in the context of his own career and milieu. Like most historians of his age, he was, he admits, formed by the Marxist, materialist ideas of the 1960s and 1970s. This meant, for example, that the origins of the second world war were to be discussed primarily in economic and diplomatic terms. Hitler was a product of Germany’s economic and political plight in the aftermath of the 1919 Versailles treaty, with which the first world war was concluded — or, on the evidence of September 3, 1939, not concluded at all. In such interpretations, the minds of Hitler and his henchmen, even the Holocaust, are merely side effects of the grand materialist narrative of cause and effect.

Overy has been progressively abandoning this view of history. This has led to conflicts with other historians, notably the Marxist Timothy Mason. Mason sees the second world war as the result of Germany’s economic crisis; Overy argues that the choices of the Nazis were at least as important. Yet The Morbid Age is the first book-length exposition of his antimaterialist view that ideas and culture make history, and that no grand historical narrative can be understood without them. “I am,” he confesses, “slightly nervous about it. I’ve never written a book like this before.”

The Morbid Age is a vast, compendious survey of the British mind and imagination in the interwar years. Politics and economics are in the background; in the foreground are the public intellectuals, the lectures, debates, meetings and publications — in short, the culture. It is the role of public intellectuals that will first strike the contemporary reader as quaint, if not exotic.

Figures such as Arnold Toynbee, John Maynard Keynes, John Strachey, Gilbert Murray, Oswald Spengler, HG Wells, Bertrand Russell and countless others spoke out and were heard by the masses. We have their equals today — Roger Scruton, John Gray, James Lovelock, Overy himself — but their role, they would admit, is marginal to the mass culture. “Public intellectuals play quite a limited role now,” Overy says.

“People can’t distinguish between so many voices clamouring for attention, and, as a result, they don’t engage with these issues very critically.”

With radio and mass-circulation news­papers, the 1920s and 1930s were at the beginning of the mass-communications explosion in the midst of which we now live. Authoritative voices could still be heard, and, as Overy says, the intellectuals felt a responsibility to inform and engage the masses — and the masses responded. “There was a kind of intellectual deference that you don’t see today.” Now we mistrust intellectuals, and the babble of voices online, on TV and in the newspapers drowns out the truly distinctive voice. The very idea of the public intellectual has become meaningless. I can only think of Clive James, a truly media-savvy intellectual, who can really be said to occupy that role, though many still bravely try.

Yet the public intellectuals didn’t make the people any less anxious. In the interwar years, they were the ones describing the big catastrophist scenarios.

So, for example, an American philan­thropist, Pryns Hopkins, proposed a radical solution to the problem of human psychic chaos: “a government-sponsored nationwide scheme of psychoanalysis clinics in which the whole population would be both entitled and strongly encouraged to be psycho­analysed”. And eugenicists, who thought the excessive breeding of the lower classes was threatening the quality of the species, wanted to introduce compulsory sterilisation, a plan that was taken up in America, but not here, where saner and usually religious voices resisted.

Overy describes the culture of the interwar years as “diagnostic”, whereas our reaction to psychic anxiety and medical fears is therapeutic. The diagnostic culture worried about society; we worry more about ourselves. Mass psychoanalysis is replaced by anti-obesity campaigns.

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