LONDON — Theresa May suffered the biggest parliamentary defeat of any British prime minister in history Tuesday as lawmakers of all stripes crushed her plan to leave the European Union.
Moments after Theresa May lost by 432 votes to 202, Jeremy Corbyn, the leader of the opposition Labour Party, announced he would seek to oust May's ruling Conservatives by bringing a motion of no-confidence in the government.
"The House has spoken and the government will listen," May told lawmakers. "It is clear that the House does not support this deal."
Earlier, the prime minister had called it the "most significant vote that any of us will ever be part of in our political careers."
Corbyn said the result was "a catastrophic defeat" for May, with 118 of the prime minister's own Conservative lawmakers voting against her plan.
May was widely anticipated to lose Tuesday's vote, but her defeat was bigger than even the most extreme predictions. Before this week, the biggest government loss in Parliament was by a margin of 166 votes and came in 1926. May smashed that record, losing by a margin of 230.
The consequences are complex and uncharted. May's government will face Corbyn's no-confidence motion Wednesday, but it isn't clear whether the opposition leader has the numbers to make that work.
The wider picture is that more than 30 months after Britain voted in a referendum to leave the E.U. — by a vote of 17.4 million to 16.1 million — the politicians have still not agreed how this should work.
Tuesday's vote was originally meant to happen in December but May postponed it in the face of almost certain defeat.
Now that it has finally happened, lawmakers must figure out what to do next. If she survives the opposition challenge, she will come back with a plan B. However, it's not clear whether any alternative plan has enough support, and the E.U. has said it won't budge in the concessions it has already given her.
If May and Parliament cannot agree on another course of action, Britain will crash out of the E.U. on March 29 without a deal, something most experts say would have catastrophic consequences.
"Every day that passes without this issue being resolved means more uncertainty, more bitterness and more rancor," May warned lawmakers after her defeat Tuesday.
Some in Parliament want a "softer" Brexit or even another referendum — dubbed "the people's vote" — which might give the public the choice between May's deal, no deal, or no Brexit at all.