Ian Birrell was a speechwriter for former prime minister David Cameron and is a contributing editor for the Mail on Sunday.

As results started rolling in from Britain’s 650 constituencies in Thursday’s election, there was a moment of exquisite symbolism. Labour leader Jeremy Corbyn was speaking to his own supporters in London, blaming everyone but himself for his side’s crushing defeat, when television screens revealed that his party had lost another seat in its northern industrial heartlands. It was Sedgefield, once the base of Tony Blair, whose centrist message triumphed three times at the turn of the century.

This single moment showed the seismic scale of the electoral eruption. Sedgefield, a former coal-mining area in County Durham, had faithfully voted Labour in every election since before World War II. But it backed Leave in the Brexit referendum three years ago, like many struggling communities — a clear sign of anger toward an establishment seen as ignoring its problems. So this brick in the “red wall” of Labour’s electoral strongholds was one targeted by the Tories under Prime Minister Boris Johnson.

Such results are extraordinary. They should be examined carefully by Democrats ahead of the 2020 election. Corbyn, a hard-left veteran like Bernie Sanders, offered the electorate a brand of reheated socialism. He proclaimed himself hero of the oppressed workers as he challenged capitalism, embraced identity politics and presented a platform of unprecedented fiscal incontinence. Yet he was firmly rebuffed by voters, who backed instead an upper-crust conservative widely seen as an untrustworthy buffoon.

One consequence of Corbyn’s incompetence is that Britain will now leave the European Union early next year. This could have dire consequences for many struggling communities in the Midlands and north of England that have turned to the Tories. But Johnson’s “Get Brexit Done” mantra struck a chord with voters fed up with a debate that has dragged on since 2016, dividing the nation and paralyzing politics. The Conservatives united the Leave vote, but Corbyn’s tortured attempt to straddle both sides badly backfired.

Nationalism has reshaped British politics. Johnson, the leading Brexiteer, who became prime minister five months ago, has booted out high-profile moderates opposing his Brexit plan. Scottish Nationalists swept seats north of the border under their sure-footed leader, Nicola Sturgeon. In Northern Ireland, Unionists are in the minority for the first time. Yet for Labour, this result goes beyond its muddled message on Brexit, the central issue confronting the country. The future of the party itself is in crisis.

Blair is the only Labour leader to have won general elections for almost half a century. Under three successors, the party has lost its grip on its historic coalition of liberal metropolitan middle-class voters with working-class supporters — and now that coalition has been shattered. Brexit was the Tory tool, but Corbyn was the cause.

Johnson took his party from minority government to a 80-seat majority despite rising only 1 percent in vote share. Labour, stained by the anti-Semitism of hard-left bigots and helmed by a leader viewed as toxic by many voters, lost 2½ million supporters. Many canvassers said they heard the same thing on doorsteps: Corbyn was not trusted to lead his nation. “Every door I knocked on — and my team and I spoke to 11,000 people — mentioned Corbyn,” said Ian Murray, the sole remaining Labour MP in Scotland. “Not Brexit.”

Incredibly, it seems the biggest indicator of Tory-backing constituencies was not their stance on Brexit but if they had high proportion of working-class voters. The first shock result of the night came from Blyth Valley in Northumberland, where about 1 in 4 children are living in poverty. Yet it switched to the party that has overseen big cuts in public spending since it gained power in 2010.

Labour has seen its worst result since 1935. “It is our communities that will suffer,” said Alan Johnson, a former postman from a tough background who became a union leader and key minister under Blair. He was visibly angry as he confronted the head of the hard-left Momentum group that controls their party in a BBC television studio. “Corbyn was a disaster,” he fumed. “Everyone knew he could not lead the working-class out of a paper bag.”

The Tories face a challenge to deliver Brexit on their promised schedule, handle any disruptive consequences and hold together their new coalition of socially conservative northerners, middle-class suburbanites and rural communities. But Labour is confronting issues of survival as a serious force challenging for power. The party must ditch Corbyn quickly rather than allow time for “reflection” (as he suggested) and the installation of another unappealing hard-line candidate. Then find a leader who can harness the energy of Corbyn’s army of young supporters and speak to populist concerns while reconnecting with more moderate-minded citizens in preparation for any stumbles by Labour’s rivals. It is about tone and trust as much as policy and positioning.

The challenge for Labour is massive. It demands honesty. Yet Corbyn on Friday morning lashed out at the media while his comrades, with typical Marxist myopia, still insisted that their polices were popular. What these deluded leftists have done is deliver traditional blue-collar communities into the the arms of the Tories — and sent their country hurtling out of the E.U.

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