Science fiction writers are made to seem prescient by confirmation bias: with time, almost any imagined future can be said to have come true. Take the pulp space opera Agent of Chaos by Norman Spinrad, in which an inept, “babbling” protagonist called Boris Johnson goes to war against a technocratic transnational government. It sounds like a satire of the present but it was written, in earnest, in 1967.

The American speculative fiction author William Gibson has said that sci-fi writers are “almost always wrong”, but over the course of a dozen acclaimed novels, Gibson himself has proven he has a gift for describing the present in terms of where it’s headed. His fame as a writer was established by his insight that much of our future would be played out in representative space, the not-there place to which people go when they stare at a computer screen – a realm he called, in the 1982 short story “Burning Chrome”, “cyberspace”. In the age of the smartphone this may seem obvious, but that story and Gibson’s first novel, Neuromancer, were written on a Hermes 2000 typewriter from the 1930s. The first website was almost a decade away, and no one he knew had a personal computer.

In another short story (“Johnny Mnemonic”, 1981) he described, 17 years before Google was founded, an “information economy” in which “it’s impossible to move, to live, to operate at any level without leaving traces, bits, seemingly meaningless fragments of personal information… that can be retrieved, amplified”. In 1996, 14 years before Instagram launched, he described in his novel Idoru a future in which “it’s easier to desire and pursue the attention of tens of millions of total strangers than it is to accept the love and loyalty of the people closest to us”.

Considering this record, it might be worrying to learn that Gibson’s latest novel, Agency, is largely a credible account of a coming apocalypse. His characters call it “the Jackpot”. “It’s multi-causal, and it’s of extremely long duration,” he explains. Over many decades, climate change, pollution, drug-resistant diseases and other factors – “I’ve never really had the heart to make up a full list, else I’ll depress myself” – deplete the human race by 80 per cent.

The Jackpot is the mundane cataclysm of modernity itself. It is hundreds of millions of people driving to the supermarket in their SUVs, flying six times a year, and eating medicated animals for dinner. “If the Jackpot is going to happen,” Gibson says, “it’s already happening. It’s been happening for at least 100 years.”

This “long-duration apocalypse” is the defining event in a yet-to-be-completed trilogy of novels that began with The Peripheral (2014). In the decades after the Jackpot it becomes possible to contact the past through a mysterious digital link. In doing so they generate alternate realities, or “continua”, in which they try to create different futures. Agency focuses on an alternate present in which Britain did not vote to leave the EU and the US did not elect Donald Trump as its 45th president. But this is no Remainer fantasy: an unspecified conflict in the Syrian city of Qamishli has brought the world to the brink of nuclear war.

Days after this interview, on 12 February this year, fighting broke out between US troops and pro-Assad forces just outside Qamishli. Confirmation bias is rarely so fast, or so unnervingly accurate.

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William Gibson is tall, rake-thin and well-dressed, in sage jeans, a dark shirt and a Japanese technical jacket. Clothes, which are sometimes integral to his plots, are among his many fascinations. He has an eye for materials and colours. On a street in Seven Dials he stops to consider the green of a front door – “Would you call that Essex Green?” – and reveals a working knowledge of the Farrow & Ball catalogue.

Gibson is softly spoken, with an accent that keeps the long vowels of his boyhood in Virginia. Born in South Carolina in 1948, he moved to Toronto in 1967 and has lived in Canada ever since. He has been coming to London since the early Seventies. “I was in my very early twenties. I was with my girlfriend, who I later married. We could only afford to stay here for a few days before fleeing to fascist countries, with more favourable exchange rates.” On the return trip, Gibson had his first encounter with the future: glam rock. “I remember thinking that it was the first time I’d ever seen anything that felt truly post-Sixties. Thinking, ‘This is not my thing, this is for slightly younger people’ – that was a first for me.”

London remained, for him, a place where things happened first. He returned more frequently in the Eighties as Neuromancer became the archetype of a new genre – cyberpunk – and a global bestseller. “[London] did feel to me, in 1986, like the future… It seemed up-and-coming. But it was also sufficiently plugged in to the rest of Europe, even then, for me to feel the energy of that. In some ways it’s been the most cosmopolitan city I’ve known.”

The Peripheral and Agency take place partly in a post-Jackpot London, a century in the future, that is technologically advanced but aesthetically antique. Gibson gestures to the wood-panelled, pelmeted, “completely over-the-top hotel drawing room” in which we sit, a “cosplay zone” of alienated history that doesn’t resemble the past as it actually was.

The rulers of this city are “the klept”, a loosely organised oligarchy that is all but ungoverned. It was on a visit to London to see his friend and fellow author Nick Harkaway in the early 2010s that the idea for the klept occurred to Gibson. Harkaway told him about London’s oligarchs, the “tiny, specialised firms that smooth things out for them, get their children into schools”, and the many ways in which City Hall – run, at that time, by Boris Johnson – went out of its way to ensure that they and their wealth enjoyed the city unscrutinised. “At first I thought, he’s putting me on, this is too weird. And then I realised it was true,” he says. “The oligarchs and the City of London merged in my mind, and when I woke up in the morning the book had completely changed.”

The klept in the novel are “a sort of cartoon, but not an unrealistic cartoon, of late capitalism”. They represent not just post-Soviet tycoons, but the amoral rich who are already devouring the present, from Silvio Berlusconi and David Koch to Donald Trump and, of course, Vladimir Putin.

Gibson has a surprising story about Russia. In the late 1980s, a little-known but highly influential think tank, the Global Business Network, started bringing together experts on the future to advise governments and corporations on the decades ahead. Gibson was one of its seers. Its annual meetings would be accompanied by tours of places its futurologists wouldn’t otherwise see; one year they visited the headquarters of Visa, which Gibson was told had “tighter security than the Pentagon”. Gibson says the GBN arranged for him to meet with FBI agents who were involved with the Russian security services, and that they told him about their plan for dealing with corruption in the post-Soviet economy, a plan they called the “self-cleaning oven”. “They were simply going to let it run, let these guys kill each other off, and when things had calmed down, they’d step in.” According to Gibson, while Boris Yeltsin was in power US intelligence blithely assumed that the turf war would play out with no clear winner. “I think, in retrospect,” he says with a wry smile, “it wasn’t a very good decision.”

Putin is the pre-eminent figure in the klept that Gibson sees emerging in the real world. He describes Russia’s reported attempts to influence the 2016 US election as “the most cost-efficient black op in human history. It was a long shot, but it did work, and every day since then they must have had a good laugh, and gotten ready to enjoy yet another day of watching this endlessly exploding grenade at the heart of American government. I doubt they’ve tried to control him very much. It isn’t necessary.”

Marketing is a recurring theme in Gibson’s work. He studies brands, and his process has involved reading catalogues of industrial products. In the new conservatism that has taken hold in the US and the UK, he sees a methodology that he traces back to “the great Republican dirty-tricks master Lee Atwater”. Trump, he observes, will “do something, and then present it the very next day as something that is going to have absolutely the opposite effect. And he knows that. It’s a mind-fuck, for want of a better term.”

The same strategy could be said of the way Dominic Cummings presents Brexit – a reactionary project that was rejected by the young and voted for most strongly by the over-65s – as the kind of disruptive innovation that might emerge from Silicon Valley. Cummings wrote on his blog that he wanted “weirdos from William Gibson novels” to work in Downing Street rather than “Oxbridge English graduates” (Cummings studied history at Oxford). Gibson was “amused”, he says, but far from flattered. “It was as though Steve Bannon had announced himself a fan.” He also thinks that Cummings has either failed to understand his books, or “glanced through” them in a clumsy attempt to compare himself to Hubertus Bigend, the puppetmaster of Gibson’s Blue Ant trilogy. “It would never have occurred to Cummings,” he says, “that Hubertus Bigend is the villain of the piece.”

Gibson has fans across the political spectrum, but he compares those to the right to “those Midwestern teenage boys who think that ‘Born in the USA’ is a patriotic anthem. They haven’t yet realised that Bruce is a big liberal. And when they do, they’re downcast. With my Twitter, I probably manage to do that to someone a few times a week.”

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What Gibson’s klept are already so well established may not bode well for the future of the planet, but they do make interesting subjects for a writer. “I’ve been curious for years,” he says, “about exactly what it is about a global climate change message that seems immediately to attract the ire of conservatives. My suspicion is that by its very nature, it suggests that the most effective response to it would be if we had something akin to the implied world government in the very first Star Trek series… the United Nations, but with teeth.”

The creator of Star Trek, Gene Rodenberry, suggested that the world government “came into existence in response to some grave, very near-potential species-wide planetary disaster”, Gibson explains. “And that’s how we finally cleaned up our act and started running the planet in a fair and sensible way. So of course, that’s anathema to someone on the Ayn Rand end of the scale.”

Gibson says technological change is often a “convenient” excuse for not changing at all. The idea that rapid technological change will suddenly solve humanity’s problems is, he says, “a more popular mythology among the very wealthy than among anyone else”. The fantastic nanotechnology described in Agency is, he admits, “a deliberately hand-wavy piece of sloppy sci-fi on the author’s part, just to enable there to be a London for me to write about in the 22nd century”. For that to happen in this continuum, we will need more than technology.

In Gibson’s 2010 novel Zero History, one character asks Hubertus Bigend “what piece of information he’d most want to have… if he could learn any secret”. If William Gibson was offered the same opportunity, what would he choose? “I would probably ask to know, in a fairly detailed way, what the future – say, 100 years from now – thinks of us,” he says. “History teaches us that it won’t be what we think of ourselves. What we think of the Victorians would have appalled the Victorians, it wasn’t at all what they thought of themselves.

“In learning that, I’d be able to infer a lot about the future. And about what’s really happening right now.”

William Gibson’s “Agency” is published by Viking