“When I was a new member of parliament, you might get one racist letter a week,” the shadow home secretary, Diane Abbott, said last year. “Now, some days, we can get hundreds of items of abuse. It’s the volume of it which makes it so debilitating, so corrosive, and so upsetting.”

In July 2017, the Conservative MP Simon Hart told a Westminster Hall debate that the Whips’ Office received “at least three credible threats to colleagues every week”. In November, the Tory Remainer Anna Soubry said that she had received 13 death threats after the Daily Telegraph named and pictured her on its front page as a Brexit “mutineer”. The Lib Dem deputy leader Jo Swinson told me that in 2015, someone threw a brick through the window of her mum’s car. “Was that because of the election, because she had a Swinson poster in the window?” she asked. “There’s a level of vitriol in Scottish politics where I hope we can put the genie back into the bottle, but it’s hard. It’s unhealthy for democracy.”

Calculated offence (and the taking of it) has always been a part of politics. Seventy years ago this summer, Labour’s minister for health Aneurin Bevan stood up in Manchester to give a speech. In it, he described the poverty and hunger of his early life, adding: “That is why no amount of cajolery, and no attempts at ethical or social seduction, can eradicate from my heart a deep burning hatred for the Tory party that inflicted those bitter experiences on me. So far as I am concerned they are lower than vermin.”

Bevan’s remark surely stands out, and is remembered today, because of its relative rarity. Now, if you talk to any MP, peer or special adviser, they will mention the blizzard of abuse that accompanies political life. Journalists feel it too, with the occasional nasty letter now replaced by endless online vitriol. Activists complain that public meetings and closed Facebook groups are mired in sourness and bad-faith arguments. People in the BBC Question Time audience are red-faced with fury. Everywhere you look, politics feels toxic.

Many in Westminster point to the Scottish referendum in 2014 as Ground Zero. While the SNP’s Nicola Sturgeon and others tried to argue for a civic, inclusive nationalism, an army of “cybernats” targeted unionist commentators online, calling them “collaborators” with a quasi-colonialist power and accusing them of treachery. (These two accusations recurred in the EU referendum, with the European Union cast in the “colonial overlord” role assigned to Westminster in 2014.)

The Scottish referendum also saw the BBC’s political editor Nick Robinson singled out by the first minister Alex Salmond following a story on the possible relocation of the Royal Bank of Scotland. Hundreds of supporters gathered in front of the BBC’s Glasgow headquarters to call for Robinson’s resignation. Robinson was used as a “symbol of the wicked, metropolitan, Westminster classes sent from England, sent from London, in order to tell the Scots what they ought to do,” the journalist claimed later.

Skip forward, and another BBC political editor, Laura Kuenssberg, is now a frequent target of both online abuse and physical threats – to the extent she took a bodyguard to the Labour party conference in 2017.

That year, having seen the sexist abuse she received, I noted that the highly personal focus on her was driven by repeated stories about her alleged pro-Tory bias on “alt-left” websites such as the Canary. After my article was published, several of Kuenssberg’s colleagues got in touch. “Having worked with her, I could not tell you where her politics lie,” one wrote. “Also having seen the state of her @ mentions [on Twitter]… I’m in awe of her ability to shut it out, get on with the job and not let it crush her.”

The attacks on Kuenssberg are, to me, the essence of this new toxicity. At heart, there is a valid issue which deserves greater discussion – the implicit assumptions that affect how the BBC frames stories, and how the demographics of its staff shape its worldview. But that structural criticism has been sharpened to a point and directed to a single individual, who is then treated as a synecdoche for everything deemed to be wrong in the world.

“BBC bias” is too big and nebulous and complex a subject to engage with, particularly online, and resolving it means sweeping organisational changes. So let’s just enjoy, in the words of a recent Canary headline, watching how “the SNP owns Laura Kuenssberg on Twitter and it’s quite delicious”. Bring me the head of Laura Kuenssberg, and let’s pretend that will solve the problem.

***

When did the current era of toxicity begin? Robert Ford, professor of politics at the University of Manchester and the co-author of a book on Ukip, points to the Scottish and EU referendums as flashpoints. They offered binary choices that “massively over-simplified complex questions, and encouraged people to identify with one [side] or the other”.

Both brought discussions of identity – sovereignty, immigration and nationalism – to the surface, encouraging emotional rather than intellectual responses. “Does JK Rowling have the right to comment on Scottish politics?” or “Is the flag of St George a racist symbol?” are more incendiary questions than “What percentage of GDP should be spent on public services?” or “Has outsourcing failed?”

The roots of the malaise are deeper, however, and some of the current toxicity must be attributed to a vicious cycle between the media and politicians. The 2009 expenses scandal encouraged a mood of “anti-politics”: the lazy but appealing idea that all politicians, not just a significant minority, were “on the take”, or “in it for themselves”. They weren’t public servants, but parasites. A friend who worked on Question Time told me that for years afterwards, the surest way to get applause on the show was to bang the table and say, “Why. Won’t. The. Politicians. Listen. To. Us.”

Melanie Onn, the Labour MP for Grimsby, worked for a trade union before agreeing to stand as a candidate in the European Parliament elections in 2009. “People were so angry,” she tells me over the phone. “In Sheffield, people were swearing and spitting at us. I had that during the [EU] referendum too, campaigning in the town square; people spat at our feet and said we were traitors to the country.”

The anti-politics mood encouraged politicians to fight fire with fire: who were the media to act as moral arbiters, anyway? On both left and right, a narrative has developed that the “MSM” – mainstream media – is out of touch with ordinary citizens’ concerns, in the pocket of billionaires, and is always wrong. Don’t listen to journalists, because they didn’t see Corbyn coming, claims the radical left. Don’t listen to journalists, because they didn’t see Brexit coming, claims the radical right.

“For all the worry about new forms of fake news, most people think our newspapers churn out fake news day in, day out,” Jeremy Corbyn tweeted on 23 August. “It’s hardly a surprise in the last four years one political earthquake after another has been missed by most of our media.”

As with accusations of BBC bias, there is a fundamentally correct point here, but it has been distorted into something cartoonish and unanswerable. Just as politicians as a class were condemned over expenses, so journalists as a class are attacked as ignorant and useless. Yet any analysis that brackets together a report from Mosul by the BBC’s Quentin Sommerville with Richard Littlejohn’s 9,567th column on “elf and safety” is obviously so broad as to be absurd. That doesn’t stop people trying, of course.

Tony Blair hugged the right-wing press close in an attempt to neutralise it; Corbyn has taken the opposite course, decrying the media in sweeping, nuance-free terms. His regular stump speech includes a rousing section criticising “the media”. Instead of useful, focused criticisms, he offers media-hatred as a rallying cry to his supporters. As Jennifer Williams of the Manchester Evening News wrote on 26 August, “responsible politicians… have a duty to think about [the] impact of their rhetoric, rather than speaking to people’s worst instincts, to their anger and their suspicion”.

That is not currently happening. For Corbyn, attacks on “fake news” fulfil the same function as they do for Donald Trump, pre-emptively debunking any and all criticism of him. And so a nuanced argument is reduced, again to a binary question: whom do you side with, Corbyn or “the media”?

This is frustrating because the Labour leader is entirely correct to note that the printed press is dominated by the right, and that overtly socialist voices struggle to get a hearing on the BBC when their opposite numbers do not. But his words are designed to signal that his supporters do not need to listen to, say, the Times’s reporting on anti-Semitism, or Jewish newspapers’ concerns about the “existential threat” that it poses. The lazy, thought-stopping response to any newspaper criticism of Corbyn can simply be: well, they would say that, wouldn’t they?

***

There are good reasons for this poisonous tango between politicians and the media. The former are the least trusted profession in Britain, according to Ipsos Mori: just 17 per cent of us trust them to tell the truth. Journalists are not far ahead, on 27 per cent. The temptation is for each group to purchase credibility by attacking the other. The effect, though, is an overall loss of respect for democracy and its institutions.

Now add in extreme political partisanship, which appears to be rising. In 2000, only 23 per cent of Democrats and 26 per cent of Republicans had a very unfavourable view of the other party. By 2016, a majority of both sides did so, according to US researchers Pew. Many on both sides described their opponents’ beliefs as “a threat to the nation’s well-being”. When you feel that strongly, it’s harder to debate with the other side in good faith, and easier to excuse abuse, threats and violence against them.

What might be driving this? One notable finding is that as we have become more relaxed about racial and cultural differences, we have become more attuned to political views as a way of finding “our people”. In America, the percentage of parents who say they would be happy for their child to date someone from another race is steadily rising. Yet in the same period, parents have become less happy about their children dating someone from another party.

Another explanation might be that the internet is poisoning the political conversation. The researchers Yphtach Lelkes, Gaurav Sood and Shanto Iyengar have linked polarisation firmly to internet usage. Because broadband coverage spread unevenly across the US, they were able to track its arrival compared with residents’ political views. “Access to broadband internet increases partisan hostility,” they reported in 2015 in the American Journal of Political Science. “Access to broadband internet boosts partisans’ consumption of partisan media, a likely cause of increased polarisation.”

The structure of the internet itself makes productive disagreement harder. In front of a screen, we are disinhibited – we say things online we wouldn’t say to someone’s face, or if others could see us. And our language is stripped of “phatic” elements, all the bits of communication that soften or modify the words: smiling, looking down, gesturing, using an obviously sarcastic tone of voice. Utterances can arrive in a contextless squirt, encouraging bad faith and knee-jerk anger.

The architecture of social networks – particularly Facebook – is also a factor. Facebook is a secretive giant, poorly understood by researchers (and perhaps even by its own engineers). It appears to poison political discussions in profound ways: by over-riding gatekeepers such as editors and political parties, it elevates the loudest, most insistent voices over the best-informed or most measured. Strong, emotionally engaging content spreads faster and wider.

Then, what legal scholar Cass Sunstein called “the law of group polarisation” takes over, where “people frequently do what they do because of what they think (relevant) others do”. If we see others spewing vitriol, our own boundary of civility shifts. If we see our friends posting endless Remainer memes, our own views towards the European Union get warmer (or we unfriend them in disgust). Either way, groups become more extreme.

Facebook is also vulnerable to targeted toxicity – the most obvious example being the Russian strategy of disinformation. The social media company has belatedly conceded that it helped spread “fake news” in the run-up to the 2016 presidential election, with the US Congress releasing 3,500 adverts from Facebook and Instagram (which the company also owns) from the Kremlin-backed Internet Research Agency. The ads tried to inflame the US’s racial divides, targeting African-Americans – or, sometimes, users with interests that heavily correlated with being black according to algorithms – with messages about the untrustworthiness of the media, the racism of the police and general exhortations to distrust everyone.

And it wasn’t just Kremlin propagandists gaming the system; sometimes it was good old-fashioned grifters, scam artists and hustlers. In August 2016, John Herrman at the New York Times uncovered a 35-year-old American who made $30,000 a month running the pro-Trump “Make America Great” page by paying a husband and wife team in the Philippines to rewrite viral political news. Scare stories proliferated, and needless to say, untruth was not a barrier to inclusion on his page. “Alert: UN Backs Secret Obama Takeover of Police; Here’s What We Know” read one headline. Pages like this spread popular false stories, such as the claim the Pope had endorsed Trump. Facebook now requires the administrators of popular pages to verify their identities, and it has reformed the extent to which advertisers are allowed to target particular groups.

As well as its polarising effects, Facebook makes it hard to distinguish high- and low-quality information sources. It encourages users to stay inside its walled garden, where a simple, clean blue-and-white design gives stories about the Pope’s Trump endorsement exactly the same visual grammar as a well-sourced, well-edited article from the BBC. In doing so, Facebook deprives users of the vital visual clues we normally use to evaluate sources: green ink letters, or supermarket tabloids full of screaming headlines and UFO pictures, are self-debunking. The same content on Facebook is not instantly recognisable as junk.

***

The giant social network, then, allowed something equivalent to an oil spill to happen in the ocean of political news. What Twitter is doing is more like a sarin attack: much smaller in scale, but potentially devastating nonetheless.

Twitter has only 335 million active users (compared with two billion for Facebook), but it is used heavily by politicians, think tank workers, radio hosts, celebrities and columnists. The miasma of unpleasantness that surrounds the political conversation preoccupies the Westminster village, but there is an awareness that it might be a phenomenon which is confined to “the bubble”. As a journalist friend put it to me: “Do we just think this because we’re on Twitter, and Twitter is a hellsite?”

Twitter is the logical extension of 24-hour news: there is endless space to fill, and nature abhors a vacuum, which in this case is filled with people procrastinating from work by indulging in petty rows. It makes pointless arguments about jerk rice feel like a proxy for tackling racism as a whole, and the site is an all-you-can-eat buffet for overworked reporters trying to cook up a story about outrage over a rapper’s new single or the costumes on Poldark. On the internet, everything is outrageous to 15 people.

Let’s phrase it this way: perhaps there are the same number of shouty idiots as there always were, but now they all have a megaphone. And a direct line to op-ed writers, newspaper editors and politicians, so their importance is magnified. The economics and consumption of online news also encourage the spread of outrage culture. In print, newspapers bundle together crime reports, horse-racing tips, lifestyle features and the weather; maybe no one actually reads the leader column, but they like to be seen reading a paper that carries one. Only the front page needs to scream: buy me!

Online, however, no one can tell what you’re looking at (see also: the proliferation of weird porn) and every article has to fight for page views, and thus advertising revenue, on the strength of its own headline and subject matter. What happened with cable news – the promotion of a new breed of freeform controversialists in exchange for ratings – is happening on the internet, too.

As journalism moves increasingly online, the bottom line is depressing: why run an expensive report about famine in Sudan that 5,000 people will read, when a cheap op-ed column about Jamie Oliver’s racist rice controversy will get 50,000 hits? In-depth features, legally sensitive news stories and long investigations make little economic sense in a purely ad-funded media environment, particularly when news is consumed through social networks and there is less brand loyalty.

Why is everyone always angry on the internet? Because it’s the simplest way to make a living. The perpetual outrage machine prints money.

***

Then comes anxiety. If economic growth is faltering, and social mobility is stalling, then politics feels more like a zero-sum game. It’s no longer about sharing out new goodies but grimly hanging on to whatever you already have. This is intertwined with race and nationalism. Diana C Mutz of the University of Pennsylvania looked at the 2016 US election to see whether the widely cited “left behind” thesis was true – whether economic troubles, particularly among non-graduates, accounted for the victory of the sexist, xenophobic, anti-media candidate, Donald Trump.

Mutz looked at a representative sample of Americans in October 2012 and 2016. She found that “change in financial wellbeing had little impact on candidate preference”. Instead, what mattered were perceptions of “American global dominance and the rise of a majority-minority America: issues that threaten white Americans’ sense of dominant group status”.

White voters, aware that they will soon become a minority, experienced “status threat”, which was exacerbated by their awareness of America’s decline as a global superpower. Conservatism surged, as well as a “nostalgia for the stable hierarchies of the past”, and an increasing defensiveness about membership of the majority group. This might account for voters’ tolerance of Trump’s “openly disrespectful statements about women, minorities, and foreigners”.

In other words, politics gets more toxic because civility takes a backseat to other concerns. Could a similar phenomenon have happened in Britain? Brexit can be seen as a revolt against immigration, infused with nostalgia for the days when Britain was at the centre of a global empire and would not have let Germans, far less Belgians, tell us how strong our lightbulbs could be.

Here, too, there has been significant demographic change. At the time of Tony Blair’s victory in 1997, 75 per cent of the electorate were white voters who left school at 16 with few or no qualifications. Now that figure is less than 50 per cent. “We have minorities getting a bigger voice, and a big section of the majority – liberal graduates – who are more sensitive to giving minorities a voice,” says Rob Ford. “That creates uncertainty about where the norms are.”

Online activists, particularly concentrated on Twitter and Facebook, generate new concepts (and new linguistic offences) with dizzying speed. A decade ago, how many people knew about “misgendering” or “cultural appropriation” or “white privilege” or “mansplaining”? Today, how many people really know the hard outlines of what constitutes each of these offences? No wonder online communication feels so fraught; sometimes, it feels as though the news is an endless parade of celebrities apologising for infractions against these new shibboleths.

In turn, that means members of the previously dominant social group are aware that they no longer set and control the rules of acceptable speech and behaviour. When commentators talk disapprovingly about the surge in “identity politics”, they often miss out a key part of the picture: previously dominant groups suddenly realising they have an identity, too. “It’s not an accident that we started talking about the ‘white working class’ as they became less dominant,” says Ford. “When they were so dominant that they were invisible, that was just ‘people’.”

Now put that anxiety about demographic change together with the viral potential of social media. Twitter has allowed Trump to shape the political news agenda to an unprecedented extent. He uses the social network to denounce his opponents in crude terms (calling a female former aide a “dog”, for example) and to undermine the investigation into Russian election interference by calling it a “rigged witch-hunt”.

As if these tics weren’t dangerous enough, he also uses Twitter to send carefully selected news stories into the political conversation, embroidering the grander narratives he is pushing. Take this tweet from 22 August, from a president not renowned for his interest in foreign policy: “I have asked Secretary of State @SecPompeo to closely study the South Africa land and farm seizures and expropriations and the large scale killing of farmers. ‘South African Government is now seizing land from white farmers.’ @TuckerCarlson @FoxNews.”

The dog-whistle here is really just a whistle: whites are under threat in South Africa, and therefore they might be in America, too. We can see a similar situation in Britain, where the arrest of former EDL leader Tommy Robinson for a breach of his suspended sentence – given for endangering a grooming trial by filming outside – was depicted as “persecution” of a “free speech martyr”. Never mind that his actions made getting convictions less likely; in our febrile online environment, appealing tribal narratives can spread unchecked far quicker than the facts can be set out by traditional news sources.

As the amount of information instantly available at our fingertips has sky-rocketed, we have dealt with the overload by extending our tribalism from opinion to facts themselves. This is called “tribal epistemology” – where information is evaluated primarily by asking whether it supports your tribe’s values, and is being pushed by your tribe’s leaders, rather than by appealing to a sense of objective truth. “There is no single, agreed set of facts on which the various sides hold different opinions,” wrote the Guardian’s Jonathan Freedland in the wake of the row over Corbyn’s attendance at a wreath-laying ceremony in Tunis. “Instead, among those most heatedly involved, the facts or evidence people see and don’t see depend on their tribal or factional affiliation.”

***

The BBC bears the brunt of this conspiratorial turn. Its editors have long been assumed by the right to be pinko metropolitans and by the left to be establishment stooges. Yet who controls the BBC’s news agenda matters vitally in an age of tribal epistemology, because it is one of the few news sources trusted by both Remain-voting urban graduates and Leave voters in former industrial communities, and everyone in between.

As a result, the battles over “BBC bias” are more fierce than ever. “We’ve had this new phenomenon – the Remoaner massive,” says one political producer. “These are people who are used to winning. They find it really hard now they’ve lost something, to accept that. The BBC is a good target, it can be used to explain the defeat. They thought we were in the tank for them.”

And something else has changed. “The old critiques were all about the tone, or the overall narrative, but this is a reaction to the very presence of people they don’t like,” says the producer. “Even them having a voice is evidence of bias.”

The BBC is also attacked because it does what social networks and internet giants have been reluctant to do: it acts as a gatekeeper. I was on the Sunday Politics in 2013 when it featured the Infowars host Alex Jones, who has since promoted the lie that there was no gun massacre at Sandy Hook and the grieving parents of the children there are merely “crisis actors”. He was robustly interviewed by Andrew Neil (who ended up miming strangling himself to death as Jones ranted unstoppably) and “balanced” by David Aaronovitch, the author of a book on conspiracy theories.

However, the BBC producer says, it would be harder to justify inviting such a figure on to a mainstream political programme today, given that Jones now runs an empire based on disinformation. “There are people where their online performance prices them out of the conversation.”

A similar rationale might apply to figures such as former Apprentice contestant Katie Hopkins, a far-right darling who is also currently taking a keen and no doubt entirely philanthropic interest in the plight of white South African farmers on Twitter. For the BBC, these kinds of judgements are unavoidable: “If we say we don’t want an atmosphere of toxicity on our programmes, we might think twice about people who can’t be constructive.”



Commentators such as Katie Hopkins contribute to a polarised, angry public realm

However, there are sometimes sound editorial reasons for inviting controversial figures on to the television, for example if they are running a political campaign, have been elected to office, or are at the centre of a news story. Then, the format of interviews is important in signalling their status. One of the results of American news channels treating Donald Trump as a joke candidate is that he was allowed to phone into the studio and spout off, where a “serious contender” would have been required to submit to a sit-down interview.

The BBC producer makes a similar point about figures such as Nigel Farage, whose regular TV appearances prompt equally regular complaints from the left, and who gets bracketed together with more extreme figures. “Do you interview them one on one, or put them in the mainstream of the conversation? Four or five people on a panel – you can’t put Tommy Robinson there, but what about Farage?”

***

So how do we make our political conversation less toxic? How do we stop bad faith preventing us from discussing politics with people on the other side? How do we stop the current situation, where too many people don’t run for office, or even join the conversation, because they don’t want to step into a swamp? Sometimes, I long for the digital equivalent of Chernobyl’s concrete shell to be built over Twitter, as everyone leaves and we all agree never to mention what happened there ever again.

The political speechwriter turned columnist Philip Collins thinks that those with a platform have a “responsibility to be civil, as courteous as we can be”, but also that the social networks need to take more responsibility for the phenomena they have encouraged. They are slowly beginning to do so: Twitter introduced a “mute” function in 2014, and now allows users to screen out unwanted replies.

The rise of ad-blocking software, and Facebook’s algorithm changes, are both making life chillier for viral news sites. Facebook itself, under pressure from politicians, is working on ways to identify scammers and grifters and to combat group polarisation. State-sponsored trolls and bots are still out there, but at least the scale of the disinformation crisis is beginning to emerge.

One of the few thoughts that gives me hope, strangely enough, is the idea of sewers. Think of the internet like an early modern city, which created more efficient, productive communities by bringing people together into close proximity, but also allowed germs to spread unchecked. For germs, read disinformation, or vitriol. What saved the city? Sewers. Our political conversation needs their modern equivalent.