As one of the founders of CND, he brought me up to fear an attack – and to protest against nuclear proliferation. Given today’s increased threat, why has nuclear armageddon fallen down our list of fears

How did fear of nuclear holocaust fade so fast? I was brought up at a time when we thought the world would probably end before we got old. But here we still are, the people who were young in the 60s, and so are the H bombs that terrified us. If anything, we are less safe now than back in the heyday of our CND demonstrations.

My father was one of the early founders of CND: a former communist who had left the party at the time of the Hitler/Stalin pact; he launched a peace march across Europe to Hungary in the 1950s. He was by nature a millenarian, living in fear of the end of the world in one way or another – and his fears were well-grounded. I went on my first Aldermaston march at 13, after hearing him speak in Trafalgar Square. Unfortunately, as was his wont, he stopped at The Bunch of Grapes pub before the march left Belgravia, and never got any further. But I went for the whole four-day trip, and every year after that, Aldermaston was the great social event for me and my friends.

My father’s fears of nuclear annihilation were so serious that halfway to a holiday in Wales, the family car had to be turned around because he had forgotten the large jar of death pills he had accumulated to mercy-kill everyone in the event of nuclear war. We had read Nevil Shute’s On the Beach. We knew what was coming. We knew exactly what Strontium-90 fallout did to you. We knew that RAF Fylingdales’ early-warning system would give us just four minutes to say goodbye. I carried banners on CND marches listing what you can do in four minutes: boil an egg, run a mile …

The songs of those marches have stayed with all who were there: “Don’t you hear the H bombs thunder / Echo like the crack of doom? While they rend the skies asunder / Fallout makes the earth a tomb.” There were many verses. “Time is short; we must be speedy / We can see the hungry filled / House the homeless, help the needy / Shall we blast or shall we build?” The refrain ends “Ban the bomb, for evermore!” But it never happened and the bombs are still here, bequeathed now to our grandchildren.

In fact, the world’s armoury has become even more unstable, in the hands of countries not officially sanctioned by the UN to possess them: Pakistan, Israel and now North Korea. Nothing about the replacement of Soviet communism by nationalist dictatorial Putinism makes the rusting Russian nuclear arsenal feel any safer than it was back then. Trump’s tiny finger on the button is terrifying. The risk of terrorists getting their hands on enough nuclear material to make lethal dirty bombs is growing, not shrinking. Already not just nuclear material, but ready-made bombs, have gone missing, or are unaccounted for. No one knows how or when or where.

The fear was rekindled with the arrival of cruise missiles at Greenham Common in 1983, launching a second wave of CND activism. But that too faded. Why? The ecological collapse of the planet took over, because it’s actually happening, right now, in the global floods, droughts and forest fires, the hottest years accelerating on the graphs. My father’s end-of-the-world anxiety turned to sustainability - he became an early climate-change campaigner, setting up a commune to grow its own produce, though it was never self-sufficient. He was only half joking when he wagged a finger at me and warned that I would arrive at his door from London, begging for a cabbage, as civilisation collapsed around us.

What should we fear most? Which will get us first – nuclear obliteration or the planet boiling? There are many kinds of complacency: the right, by nature, tends to trust that some notional global establishment will somehow sort things out before catastrophe strikes. Or science will fix it just in time. Maybe, as the risks rise, there is a limit to the amount of fear you can feel at any one time, and you are left to shrug helplessly at whatever insanity Kim and Trump may commit. Astronomers know without doubt the world will end, many millennia hence. The question is whether we end it all now, out of sheer human idiocy.