On Monday in North Carolina, Donald Trump promised to pull off a "Brexit, Plus, Plus, Plus." He was referring to the surprise vote in June by people in the United Kingdom to leave the European Union.

Given the polls at the time in America, pollsters in London saw that boast as a stretch — but early Wednesday morning, Trump delivered on that pledge.

At the election party Tuesday night at the United States Embassy in London, most Britons were shocked by how well Trump was doing. Munching on burgers and shakes from Shake Shack, they watched in disbelief as the electoral map turned increasingly red. For some, the results confounded their notion of America as an open, tolerant society.

"It's just blown my mind that an individual such as Trump can have such a following," said Jared Reeks, a member of Young Leaders UK, a group of Britons who are fans of America and focused on sustaining and improving relations between the two countries.

Reeks likened Trump's showing to the shock that followed the Brexit vote, when more than 17 million Britons voted to cut ties with the EU, the world's largest collective economy.

"It's terrifying," Reeks said of the Brexit vote. "It's kind of like, 'Well, what do we do now?' And we're still trying to figure that mess out, and the reality is: No one has a clue."

Analysts will chew over the 2016 race for years, but Britons at the embassy party already were offering off-the-cuff analyses. Kate Hawley, who works in forestry with the U.K. government, saw many parallels between the types of people who supported leaving the EU and those who have backed Donald Trump.

"It's overwhelming for me to see the huge amount of disenfranchised people who feel the government has failed them," said Hawley as CNN prepared to call Ohio for Trump. They feel "that there is nothing left for them — that any change is good."

Hawley likened some rural Trump supporters to people in the northeast of England, who saw Brexit as a protest vote against the establishment by communities that had been left behind by globalization and felt ignored by the political leaders in London.

For Americans, Hawley offered words of comfort, while freely admitting she has struggled at times to follow her own advice.

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