Ten years on from Jo Cox’s murder, Kim Leadbeater fears that the consensus around “kinder, gentler politics” in the wake of her sister’s death was short-lived.

“Sadly and regrettably, over the last decade things are worse,” she says. Cox, the Labour MP for Batley and Spen and mother of two young children, was murdered outside a library in West Yorkshire in June 2016 by an English nationalist.

In the aftermath of Cox’s killing, the then Labour leader, Jeremy Corbyn, issued the call for “a kinder and gentler politics”, echoed by then prime minister David Cameron’s call to “drive out” intolerance.

Just hours before Cox was killed, Nigel Farage unveiled the infamous “breaking point” poster – depicting Syrian refugees lining up at a European border, cementing the politics of scapegoating and fear into the Brexit referendum campaign.

A decade on, intolerance appears to have prevailed.

Police are encouraged to disclose ethnicity and nationality of some offenders, and Britain braces for far-right unrest whenever they are not white.

After Henry Nowak was murdered by a Sikh man in Southampton as police dismissed Nowak’s dying plea for help, Farage called for “pure, cold rage”. Rioting followed. Later, racist mobs burned people out of their homes in Belfast.

Last summer, protests outside hotels housing asylum seekers were persistent, while St George’s flags were hoisted from windows, bridges and lamp-posts in what was described by some as a celebration of Britishness, and others as an aggressive symbol of anti-immigration sentiment.

In 2021, the Conservative MP David Amess was murdered by an Islamic State sympathiser. The same year, a teacher from Batley Grammar school – in Cox’s old constituency – went into hiding, amid fears for his life, after showing his pupils a cartoon of the Prophet Mohammed from the French satirical magazine Charlie Hebdo in an RE lesson.

Rob Ford, professor of political science at Manchester University, believes “a kinder, gentler politics” was always a vain hope. He believes Brexit “accelerated rather than created” the deeper forces driving populism.

“There’s no centrist position on prejudice,” he said, arguing that where postwar politics of class and economics allowed for compromise, politics built around identity and values tends toward absolutism.

This produces “increasingly extreme definitions of the in-group” on the right and “purity spirals” on the left, with rivals dehumanised as “embodiments of evil”.

Ford pinpoints the shift from economic to identity politics as beginning with the 1960s liberation movements – “gay rights, women’s rights, anti-racism” – which were about “something more fundamental” than “how to get half a loaf more of bread”.

As the rise in living standards stalled, the right coalesced around culture rather than tax rates, while deindustrialisation led voters to believe that government “isn’t going to come to the rescue”. This, he adds, encourages tribal allegiance.

Age has also become the strongest predictor of voting preference, and right-populist parties draw heavily on older voters, who Ford calls “the fat kid on the seesaw” thanks to their numerical and turnout advantage.

But he cautions against taking a “sepia-toned” view of the past, describing how the performative has long been a feature of politics – from the “fireside chat” radio broadcasts used by interwar prime minister Stanley Baldwin to connect with the public, to the pipe 1960s and 70s PM Harold Wilson used to project a “man of the people” image.

Nonetheless, social media has supercharged “political entrepreneurs” who perform outrage – “having discovered one of the oldest lessons in politics, that anger is a much easier emotion to excite than hope” – while reducing the control parties have over messaging, Ford says.

The negative impact social media has had on some politicians has been profound.

“We just have a tidal wave of abusive and racist communications online,’ Diane Abbott, MP for Hackney North and Stoke Newington, says. “It’s not the views themselves that are the problem, it’s the way people increasingly frame them abusively.”

Abbott no longer travels on public transport or holds meetings alone – “unthinkable” when she was first elected in 1987.

“You have to be careful you’re not open to physical attacks,” she says. “I’ve had young women come to intern with me and they’ve said at the end: ‘I was thinking of going into politics and when I see the abuse you have to put up with, I’ve changed my mind.’”

Jess Phillips, MP for Birmingham Yardley, says former prime minister Boris Johnson bears some responsibility for normalising “treachery” rhetoric after Brexit.

Phillips says “the left also has its actors,” and criticises Green party leader Zack Polanski and MP Hannah Spencer for framing politicians as “out of touch” and “posh”.

Institutions – police, parliament, intelligence agencies – take threats far more seriously since Cox’s death, though nothing prepared Phillips for the feeling of being “hunted” that it triggered, even though she had been experiencing online “pile-ons”, including rape threats, long before Cox’s murder.

Phillips wants a broader debate about whether social media platforms should be treated as publishers making editorial decisions, which would increase their liability for content that is algorithmically pushed into people’s feeds.

Abbott believes a “less uncivil” US president could shift the tide. Phillips, who has seen colleagues “consumed” by Facebook abuse to the point of mental health crises, is hopeful scrutiny of social media companies is growing – and takes heart that she gets “way more kindness than hate”.

The social media ban for under-16s announced this week, and the Online Safety Act, which requires platforms to take action on content that is illegal or harmful to children, are tangible examples of the government slowly taking a tougher line on big tech. However, MPs have said the government needs to go further to address the algorithmic amplification of “legal but harmful content”.

Ford says what has been lost is the “recognition of the human on the other side of the aisle” – work which Jo Cox’s family and friends have dedicated themselves to, through the community cohesion charities the Jo Cox Foundation and the Together Coalition.

Leadbeater is now MP for Spen Valley, the successor constituency to her sister’s seat. Leadbeater was first elected in a 2021 byelection – after a campaign in which she was chased and heckled for her stance on LGBTQ+ rights – and remains inspired by her sister’s 2015 maiden speech in parliament, in which she said: “We are far more united and have far more in common with each other than things that divide us.”

“You’ve got to listen to people,” Leadbeater says. “And you can’t just label people because they are basing their views on their lived experience, they’re basing their views on, on things they have been told, whether that’s true or not true. But what you can’t do is just dismiss people.”

Jo Cox’s widower, Brendan Cox, argues politics should not be “devoid of passion or even anger” — but needs to ensure discourse stays “decent and honest and constructive”, while tackling social media’s tendency to give “the most extreme voices the most feedback”.

He co-founded the Together Coalition, which has convened the Independent Commission on Community and Cohesion. Last month, the commission launched the National Conversation, inviting the public to share their vision for their community and country via surveys, voice notes and events, using AI to map responses. The project aims to “give the mic back” to the sensible majority.

Cox cites the World Values Survey ranking the UK among the world’s most open and tolerant countries.

“I think the public are sensible,” he says. “I believe in the wisdom of the British public. The second thing that gives me hope is I think that the era of big tech being able to do exactly what they want is over … I think the blinkers have come off.”