UK Voters Decide Who They Want to Resolve Brexit Impasse

(L) Conservative Party leader Boris Johnson casts his vote at Methodist Central Hall in the Westminster area of London on Dec. 12, 2019, and (R) Britain's Labour Party leader Jeremy Corbyn casts his vote in the Islington area of London on Dec. 12, 2019. Frank Augstein, Thanassis Stavrakis/AP Photo

LONDON—Britons who have endured three years of wrangling over their country’s messy divorce from the European Union cast ballots Thursday in an election billed as a way out of the Brexit stalemate and one of the deeply divided country’s most important votes since World War II.

The contest pits Prime Minister Boris Johnson, who says he will take Britain out of the EU by Jan. 31, against opposition leader Jeremy Corbyn, who promises another referendum on Brexit.