The autumn is coming, though it might be better to adopt American English, and think of it as the fall: out of the languid, heady days of summer, and back into the dysfunctional, Groundhog Day-esque deadlock that currently passes for national politics. Conference season will be here in a few weeks’ time. The Conservatives will talk in delusional terms about Brexit, and a lot of what they say will be viewed through the prism of a supposedly looming leadership contest. Labour will also smooth over the realities of leaving the EU, presumably continue to be dogged by evidence of antisemitism – which clearly runs much deeper and higher than some people would have us believe – and possibly have a minor factional scrap about its so-called democracy review.

After a summer that has flagged the realities of a warming planet, climate change will get precious little attention

Meanwhile, many people will wonder why there is such little interest in an array of massively important subjects. Labour is bound to sound off about the condition of the country more than the Tories, but even so, on both sides the no-shows will be obvious. Even after a summer that has flagged the realities of a warming planet in no end of vivid ways, there will probably be precious little attention paid to climate change. No one is likely to speak convincingly about how to radically change a benefits system that is broken beyond repair; nor about a schools system that is increasingly unfit for the future. The profound challenges presented by an ageing population will be skirted over, at best. The fact that councils are now colliding with bankruptcy might be mentioned, but is unlikely to lead to any deep discussion of how to change our system of local government.

These omissions are partly to do with the way Brexit has sidelined debate about anything else, but the sense of absence runs deeper, into the online spaces in which politics now plays out. There, the modern divide between right and left is reducible to two tribes in a constant state of excitation, stoked by whatever is today’s controversy, and usually in no mood for anything that might unsettle their core convictions. Each camp tends to comb the culture for anything suspect, and then explode.

This has grim consequences, not least for our collective sense of priorities. An example: some people may have missed it, but last week brought news that the oldest and thickest ice in the Arctic has started to break up. But on my Twitter timeline, there was much more interest in the controversy that had been kicked off shortly before by the Labour frontbencher Dawn Butler, when she admonished Jamie Oliver for the “appropriation from Jamaica” embodied by his new brand of “jerk rice”. The furore that followed was essentially a massed wrestling bout conducted by the same participants as ever: a flimsy replay of the burqa controversy Boris Johnson had triggered a couple of weeks before.

If these episodes sometimes have the surreal feel of things pulled into the real world from fiction, it is perhaps not surprising that the best book about British politics I have read in some time is a just-published novel. Perfidious Albion is the second book by the 39-year-old Sam Byers, whose keen sense of his time has echoes of Martin Amis and Jonathan Coe. His story is a fusion of Brexit, the Twittersphere and “opinion” websites, and the all-pervading power of a tech company called Green. What burns from its pages is a vivid picture of how much politics has been uncoupled from the nitty-gritty, and floated off into an orbit all its own.

Facebook Twitter Pinterest Aneurin Bevan visits the first NHS hospital, Park hospital (now Trafford General) in Manchester, in 1948. ‘Such trifles as the welfare state and the post-war education system were basically the work of centrists.’ Photograph: Trafford Healthcare NHS/PA

In the Albion of the title, the politicians who succeed are the ones who can surf waves of online controversy and market themselves as being “barely a politician at all”. Meanwhile, for all their passion, many people who are involved in politics are in constant danger of losing any grasp of reality. When the couple at the heart of the story sit down to dinner, a nightly ritual ensues: “While they ate, they talked about the day’s events on the web, asking each other if they’d seen this or that post, tracked this or that social media shitstorm, or caught a glimpse of whatever eye-rolling thinkpiece was currently whipping up derision across right-thinking networks.” One of them finds fame on an “opinion” platform called The Command Line, where his editor instructs him in the art of provocation for provocation’s sake : “You’re nobody until somebody really hates you … And now someone really hates you, I think it’s fair to say you’re finally really somebody, no?”

This is the backdrop to the rise of a character named Hugo Bennington, a rightwing politician who is essentially 70% Nigel Farage and 30% Boris Johnson. His mission is simple: “Brexit was over, but the energy it had accumulated had to be retained. Fears needed to be redirected. Hatreds needed to pivot.” Each time he writes, tweets or appears on TV, his leftwing adversaries combust, which only increases his profile. As with Johnson and Donald Trump – and, in a very different way, Jeremy Corbyn – he seems less interested in the complexities and challenges of actual power than in something else: standing at the head of a movement, somehow embodying his time, and remaining in the company of people who agree with him.

Perfidious Albion by Sam Byers – review Read more

The key event happens when a female character responds to Bennington’s complaints about the supposed oppression of white men with the sarcastic hashtag #whitemalegenocide. With the help of a far-right group called Brute Force, Bennington whips up the resulting controversy into a major political episode that breaks out of social media and starts to define events on the street. It all gives rise to a lot of noise, but changes nothing. As with the best zeitgeisty fiction, the story describes events that could happen tomorrow, and conveys a sense that we are moving at speed from one world into another.

To use a word endlessly parroted online, our new political culture has superseded the dominance of what some people call “centrism”. To the extent that the latter was eventually defined by callow, fortysomething white men and such disasters as the Iraq war and the financial crash, its time was deservedly up. A new centrist party is an assuredly terrible idea. But quite a few babies have been thrown out with the bathwater. The word’s etymology is questionable, and to use it retrospectively seems crass, but such trifles as the welfare state and the postwar education system were basically the work of centrists. More recently, so were Sure Start, the minimum wage and equal marriage. These things required planning, coalition-building and a willingness to listen to an array of opinions. The kind of shrill belligerence that now defines debate would probably have killed them before anyone even got started.

Prospect of a new UK party grows as Brexit shifts ground at Westminster Read more

One big tension defines where British politics has arrived. On both sides, there are a lot of people – from no-deal Brexiteers to the Corbyn hardcore – who seem to think that they are the custodians of their own variety of purity. What we are perhaps discovering is that this mindset may actually deliver the reverse: a polluted politics in which even people in positions of power keep very questionable company, debate tends to look like an indecipherable mess, and the biggest casualty is a national conversation that feels in any way useful.

Until that changes, politics will suggest so much irrelevance, not least to the millions of voters for whom the online whirl is another planet. Perfidious, according to the Oxford dictionary, means “deceitful and untrustworthy”: an appropriate description not just of modern England, but of the politics it has spawned.

• John Harris is a Guardian columnist