Prime Minister Theresa May believed she had constructed an inescapable trap for British voters. Most observers and pundits, myself included, assumed it would work. Last night, the voters delivered a stunning surprise. Rather than walk into the trap, they knocked it over.

Half of British society wished to stay in the EU. Forty-eight percent voted Remain in the June 2016 referendum, and they have not changed their minds. A year-long series of polls on the question, “Was Britain right or wrong to quit the EU?” shows no trend at all. The latest poll, June 7, reveals a perfect 45-45 split.  

Theresa May gambled that she could ignore those disgruntled Remainers. In September 2015, the Labour party had selected as its leader Jeremy Corbyn, a left-winger with a decades-long record of sympathy for terrorist groups—and a management style so chaotic that he triggered the resignation of his entire front bench in February. Corbyn had also played a transparent double game on the EU referendum. His party supposedly opposed Brexit—but his own behavior during the referendum campaign strongly suggested to Labour Remainers that he retained the traditional left-Labour dislike of the EU. He even took a holiday in the middle of the campaign.

Extreme in his views, ineffectual in his leadership, Corbyn found himself by spring 2017 at a nearly two-to-one disadvantage in polls. As I reported here in the spring, Labour’s own pollsters regarded almost every seat in the country as at risk.

Corbyn-led Labour is polling at about 20 percent in the election scheduled for June 8. Ancient Labour redoubts—Scotland, Wales—are suddenly competitive for the Conservatives. Labour insiders reckon that seats last time won by 6,000 votes must be regarded as likely lost; seats won by 8,000 as up for grabs; and seats won by the (by British standards) massive margin of 10,000 still requiring a lot of work.

May saw an opportunity to win a crushing majority. She took it for granted that the broad middle of British opinion had no choice: It must vote against Corbyn. That left her free to pivot rightward, vacuuming up the most extreme anti-EU votes from the remains of the U.K. Independence Party. She opted for what the British call “hard Brexit”: rapid and total severance of Britain’s relationship with the EU.

Many things went wrong for the Conservatives in the 2017 election, very much including President Trump’s bizarre Twitter rampage against the popular Labour mayor of London in the wake of a terrorist atrocity.

But lurking behind all the manifold specific problems was a deeper discontent: the lingering resentment of the British moderate center at being hustled out of the EU on false promises. The Leave campaign bus was blazoned with a promise that quitting Europe could add 350 million pounds per week to the National Health Service.

The Vote Leave campaign bus (Christopher Furlong / Getty)

That preposterous figure (among other things, it ignored money that the U.K. received back from the EU) was crassly abandoned within weeks of the vote.  There would be no extra money for hospitals … no extra money for anything, as it turned out, as the pound crashed and the U.K. economy slowed in the wake of the Brexit vote.

May believed she could build a big parliamentary majority from the center to the fringe on a program that served the fringe at the expense of the center—because the main opposition party was also doing the same. The center had no good choices, and must accept her as the less bad. Instead, they punished her as the author of their dilemma. The early exit polls suggest the mechanics of what happened: May’s populism boosted her support among white working class voters, but not enough to tip Labour strongholds her way; meanwhile, she lost ground among middle-class metropolitan voters, costing the Conservatives seats through wealthy southeastern England. The Conservatives even lost Canterbury, a Tory seat since the advent of universal male suffrage in 1918.

The disaffected middle class did not punish May so roughly as to bring the dreaded Corbyn to power. But through some mysterious collective wisdom, they did just enough to break her power, cut short her career—and very possibly reopen the question whether Brexit cannot be stopped.