London, United Kingdom – Ten years after Britons voted in the Brexit referendum to leave the European Union, opinion polls show the public is still grappling with the consequences of its decision.

As Keir Starmer resigns to make way for the seventh British prime minister in a decade, the current political instability has its roots in the ominous spiral that Brexit unleashed with David Cameron’s resignation following the referendum in 2016.

A YouGov survey conducted this month to mark the referendum’s 10th anniversary found that just 30 percent of Britons now believe leaving the EU was the right choice. This figure was 64 percent when the vote was held on June 23, 2016. But now, a clear majority of 57 percent think it was wrong to leave the bloc, and six in 10 judge Brexit as an outright failure.

The arguments for a yes vote that consumed the referendum campaign – sovereignty, the British pound, economic independence, austerity and smashing the burden of unnecessary red tape – have settled into something closer to a deadlock than a consensus.

Yet with a recent analysis by the Bank of England indicating the UK economy has shrunk by 6 percent due to the effects of the departure, it is no longer disputed among many economists that the honeymoon is over. Brexit has morphed into “Bregret”, as some pollsters and commentators have quipped.

However, the lasting legacy of Brexit may prove not economic but societal – a slow reshaping of the country’s political culture, its tolerance for extremity and the discourse about who belongs, who should be an outsider and how to exclude, no matter how toxic the polarisation gets.

On such measures, the decade since the referendum has been costly.

A toxic culture of antipathy

Anxieties and racism in Britain around immigration, especially concerning people of colour, have a long history. The Brexit referendum offered the latest licence for exclusionary attitudes. By turning a complex question of EU membership into a vote on control of the borders, pro-Brexit campaigners infused the politics of migration with a moral charge it has gripped onto firmly.

According to Tahir Abbas, the director of the Centre on Radicalisation, Inclusion and Social Equity at Aston University, “Brexit was a long-term process” that emerged from decades of euroscepticism within the Conservative Party. What is increasingly evident, however, is the powerful rallying of opinion and people that Brexit achieved, he said.

“Brexit is a much more recent phenomenon that mobilised Islamophobia, particularly through the infamous poster that Nigel Farage stood before, showing pictures of tens of thousands of brown-skinned people seemingly making their way across Europe and into the UK,” Abbas told Al Jazeera.

Now, the rhetoric that once sat at the fringe – that the country is being “invaded”, that asylum is a racket, that minorities such as Muslims do not share “British values” – has moved steadily towards the centre of acceptable debate. Phrases that would once have ended a minister’s career in government have increasingly been normalised.

With the rhetoric has come policy.

Successive governments, chasing the electorate that Brexit revealed, have competed to out-toughen one another on immigration: offshore processing, the threat to leave the European Convention on Human Rights and schemes to deport asylum seekers to third countries that courts have found unlawful.

Measures once regarded as unacceptable – such as detention of migrants and asylum seekers without defined limits, the criminalisation of rescue operations at sea and the rhetorical conflation of refugees with criminals – have been normalised under the guise of border control.

Phrases such as “Stop the Boats”, a slogan of the Conservative Party to demonstrate its anti-immigration credentials, have been elevated by leaders of the far right, like Tommy Robinson, who enjoys the endorsement of trillionaire Elon Musk.

“Enough is enough. … Stop the invasion” was a crowd chant at the “United the Kingdom” march in London, led by Robinson in September. Slogans such as “protecting our women and children” have been regularised to infer that sexual crimes targeting women and children are somehow the domain of brown and Black people, “the foreign invaders”.

From discourse to violence on the street

A week before the referendum, a 53-year-old man killed Jo Cox, a Labour Party legislator and mother of two, in northern England. “Britain first” and “This is for Britain,” Thomas Mair shouted as he shot and stabbed her to death.

In the Belfast riots this month, toxicity in public discourse against people of colour translated into fire and violence. After a knife attack by a Sudanese national, masked crowds moved through the city for several nights, torching homes, businesses and vehicles and going door-to-door in an effort to identify houses occupied by immigrants. This was not random.

A group of volunteer monitors over a period of eight months before the riots had warned the Police Service of Northern Ireland about a “hit list” prepared by anti-immigration activists that included addresses that were the same properties targeted this month.

Not all far-right and racist politics in Britain are tied to Brexit. But the fracture has worsened the resurgence of hateful politics, solidifying the kind of nationalism that threatens hard-fought commitments in the post-World War II era to public democracy, according to Nichola Khan, an anthropologist and migration expert at the University of Edinburgh.

She argued that cultural diversity, a treasured British value, is faced with risks of erasure.

“The focus on migration is specious. Most people know this but find themselves without the means to effectively push back and resist,” she said.

The burden of lived experiences of exclusion and racism is heavy for Britain’s Muslims, especially women who choose to wear clothing that distinguishes their faith, than for any other minority community.

A campaign to brand Muslims as outsiders to “British values” continues, not only in mainstream political discourse but also online.

Discrimination on the street makes no distinction between a third-generation British Muslim doctor, an EU citizen of colour and the “illegal migrant” that tabloid media vilify. British Muslims, therefore, are facing a double-edged sword of prejudice against their ethnicity and their faith.

The disinformation engine goes online

The polarisation and division that Brexit has accentuated breed uncomfortable truths. In a divided society, the fuel for information warfare consumes domestic underclasses.

This is true in the case of underprivileged white working-class communities who feel angry at the austerity and post-industrialisation collapse of northern British towns but find themselves blaming immigration alone. The same communities voted in large numbers for Brexit while polling data suggested that ethnic minorities were more likely to vote to remain in the EU.

According to Amil Khan, head of Valent, an organisation that unpacks disinformation, the “leave” campaigners’ victory vindicated new approaches to information communication and the idea that technology and data could bypass the old gatekeepers of traditional media, vote banks and community champions.

After Brexit, a generation of strategists entered the market “younger, more tech savvy and less rule-bound than the generation that preceded them”, Khan said.

This also gave rise to new actors offering ancillary services, such as bot farms, which have increased their capacity, helping to spread disinformation, a problem that increased innovation in artificial intelligence could exacerbate.

Khan contended that although groups such as Muslims are persistently targeted by these campaigns, the ultimate goal is control over government and influence over policies.

The reckoning ahead

The UK’s economic woes are likely to continue to force deliberations about how best Britain should align with the EU in a climate where sovereignty and immigration remain contentious issues in public discourse and where a resurgent Reform UK party under Farage stands ready to brand any concession a betrayal.

As debates rumble on, the societal implications are unmissable, and they are tragic.

Ten years of centring migration as the master key to all societal grievances and socioeconomic problems has coarsened the discourse, normalised extremes and increasingly put families and individuals of non-white backgrounds, particularly British Muslims, in harm’s way.

If this trajectory is not rectified, Britain will need more than just a healthy economy to repair trust among its citizens.