On a day of humiliating setbacks, British Prime Minister Boris Johnson suffered a major defeat in Parliament on Tuesday night as rebellious lawmakers voted to seize control of the Brexit agenda, prompting the embattled prime minister to say he would call for a new general election. The 328 to 301 vote, made possible by fellow Conservatives who turned their back on Johnson’s pleas, cleared the way for his opponents to introduce a bill Wednesday that would seek to prevent Britain from leaving the European Union without a deal Oct. 31. It was a momentous day in Britain’s centuries-old Parliament as the legislature rose up to successfully challenge the power of the prime minister and his government over vital Brexit policy. Even if they can force Johnson to seek a delay to that deadline, any extension would have to be approved by each of the other 27 EU nations. The cross-party rebels are determined to prevent a “no-deal” Brexit because of fears it would gravely damage the economy and plunge Britain into a prolonged recession while also leading to possible medicine and food shortages. The vote came hours after Johnson suffered a key defection from his party, costing him his working majority in Parliament. On a day of high drama and acerbic debate in the House of Commons, lawmakers returned from their summer recess to confront Johnson over his insistence that the UK leave the European Union on Oct. 31, even without a withdrawal agreement to cushion the economic blow. Many shouted, “Resign!” and protesters gathered outside Parliament to call for Britain to remain in the EU. A new general election would take Britain’s future directly to the people for a third general election in four years. It is not clear Johnson would immediately get the two-thirds majority in Parliament needed to call a fresh vote because opponents are wary he might postpone the election date until after Brexit has taken place. “I don’t want an election but if MPs vote tomorrow to stop the negotiations and to compel another pointless delay of Brexit, potentially for years, then that will be the only way to resolve this,” Johnson said minutes after he lost the vote in Parliament. Earlier Tuesday, two other prominent Conservatives signaled their intention not to seek re-election rather than bend to Johnson’s will. Former Cabinet minister Justine Greening and former Foreign Office Minister Alistair Burt also signaled their intention to stand down. Jeremy Corbyn, leader of the main opposition Labour Party, lambasted the weakened Johnson and accused him of “riding roughshod” over the constitution in order to crash Britain out of the EU without a deal. He said he will not agree to a new election until legislation preventing a “no-deal” exit is in place. “He isn’t winning friends in Europe. He’s losing friends at home. His is a government with no mandate, no morals and, as of today, no majority,” Corbyn said. Johnson, who became prime minister in July, has tried to crack down on members of his Conservative Party who oppose his Brexit plans, warning they would be expelled from the party if they supported parliamentary efforts to block or delay the withdrawal. Dominic Grieve, who was attorney general in David Cameron’s government, says the expulsion threats demonstrate Johnson’s “ruthlessness.” Greening said she feared her beloved party was “morphing into Nigel Farage’s Brexit Party.” Former Treasury chief Philip Hammond warned of the “fight of a lifetime” if officials tried to prevent him from running in the next election. All three oppose Johnson, with Hammond saying he expected a procedural motion to take control of business. If it passed, a vote to block a no-deal would be considered Wednesday. Time to block a “no-deal” departure is running short. Johnson last week maneuvered to give his political opponents even less time to block a chaotic no-deal Brexit, getting Queen Elizabeth II’s approval to suspend Parliament. His outraged critics sued, and attorneys arguing the case at a court in Scotland completed submissions Tuesday. The judge could rule as soon as Wednesday.