Parliament approves proposal designed to prevent possibility of no-deal departure from the EU on October 31.

The United Kingdom‘s parliament has voted to postpone a decision on whether to back Prime Minister Boris Johnson‘s Brexit deal, effectively forcing the British leader to request a three-month Brexit extension from the European Union instead.

At a rare weekend sitting of parliament on Saturday, MPs voted 322 to 306 in favour of an amendment brought forward by former Conservative MP Oliver Letwin which prevents Johnson’s Brexit deal being approved until all the legislation needed to implement it has been passed through parliament.

Letwin said he hoped Johnson’s deal would succeed, but he wanted “an insurance policy” which prevents the UK from exiting the EU without a deal on the existing October 31 deadline if the necessary legislation can not be approved by then.

Reacting to the defeat, Johnson pulled a highly anticipated vote on his freshly created withdrawal agreement, meaning he will now be obliged to ask the EU for a Brexit delay until January 31, in line with legislation passed last month.

Johnson, who has repeatedly pledged to take the UK out of the EU by October 31, also pledged to continue to pursue a departure by the end of this month and bring his plan back to MPs for consideration next week.

“I will not negotiate a delay with the EU and neither does the law compel me to do so,” he told Parliament.

“I will tell our friends and colleagues in the EU exactly what I have told everyone else in the last 88 days that I have served as prime minister: that further delay would be bad for this country, bad for the European Union and bad for democracy.”

EU urges UK to outline ‘next steps’

Any further delay to Brexit, which has already been postponed twice from the original March deadline, requires the EU’s approval.

Mina Andreeva, a spokeswoman for the European Commission, said the EU’s executive branch had “taken note” of Saturday’s vote in the British parliament and called on the British government to “inform us about the next steps as soon as possible”.

🇪🇺🇬🇧 @EU_Commission takes note of the vote in the House of Commons today on the so-called #Letwin Amendment meaning that the #WithdrawalAgreement itself was not put to vote today. It will be for the UK government to inform us about the next steps as soon as possible. — Mina Andreeva (@Mina_Andreeva) October 19, 2019

Jeremy Corbyn, leader of the main opposition Labour Party, meanwhile said Saturday’s defeat represented an “emphatic” rejection of Johnson’s Brexit plan and called on the prime minister to “comply with the law” and request a Brexit delay.

“He can no longer use the threat of a no-deal crashout to blackmail members to support his sellout deal,” Corbyn told Parliament.

Corbyn had earlier called on his party’s 245 MPs to reject Johnson’s withdrawal agreement, arguing it would be a “disaster for working people” and was “even worse” than the previous deal negotiated by Johnson’s predecessor, Theresa May, which was rejected three times by Parliament.

‘Extraordinary day’

The dizzying political drama inside the House of Commons coincided with mass rallies outside Parliament, where hundreds of thousands of anti-Brexit demonstrators gathered to call for a second vote on the UK’s membership of the EU.

Protesters, many wearing blue berets emblazoned with yellow stars symbolizing the EU flag, poured out of subway trains and buses for the last-ditch effort.

Al Jazeera’s Andrew Simmons, reporting from Westminster, said it had been an “extraordinary day”.

“It was the first time that Parliament has sat on a Saturday since 1982, 37 years ago, when they met to discuss the Falklands war,” Simmons said.

“This was a major event, and yet, it didn’t happen,” he added, referring to the now-deferred vote on Johnson’s deal.

Stephen Barber, a senior research fellow at the Berlin-based Global Public Policy Institute, meanwhile described the political developments as a “huge setback” for the government.

“It takes away the card from Boris Johnson that he really wanted to play, which was that ‘it’s my deal or its no deal and we crash out on October 31’,” Barber told Al Jazeera. “Now, that’s no longer the case.”