LONDON • British Prime Minister Theresa May warned Sunday that it would be “a potent symbol of Parliament’s collective political failure” if a Brexit delay meant that the U.K. has to take part in May’s European Parliament election — almost three years after Britons voted to leave the bloc.

Writing in the Sunday Telegraph, May also cautioned that if British lawmakers failed to back her Brexit deal before Thursday’s European Council summit, “we will not leave the EU for many months, if ever.”

“If the proposal were to go back to square one and negotiate a new deal, that would mean a much longer extension … The idea of the British people going to the polls to elect MEPs (Members of the European Parliament) three years after voting to leave the EU hardly bears thinking about,” she wrote.

May is expected to try to win Parliament’s approval of her withdrawal agreement from the EU for the third time this week. After months of political deadlock, lawmakers voted Thursday to seek to postpone Brexit. That will likely avert a chaotic British withdrawal on the scheduled exit date of March 29.

Britain’s Prime Minister Theresa May speaks to lawmakers in Parliament.

the associated press