U.K. Voters Deliver Stunning Setback to Theresa May’s Conservatives

LONDON—British voters delivered a stinging rebuke to Prime Minister Theresa May and her ruling Conservative party, depriving her of a majority in Parliament and thrusting the country back into a new period of uncertainty as it prepares to depart from the European Union.

Mrs. May called the election in April, betting she could substantially increase her party’s 17-seat majority and strengthen her hand as she negotiated an EU exit. As…