LONDON — It was billed as the day that might break the Brexit deadlock. In the end, as with everything else in this tortured process, Saturday delivered more confusion and delay.

Abuzz with anticipation, the British Parliament gathered for its first weekend sitting in 37 years, a marquee event billed as "super Saturday."

Prime Minister Boris Johnson wanted to get Parliament's approval for his divorce deal, a major step toward leaving the European Union at the end of the month.

However, rebel lawmakers had different ideas.

In a day of high drama and heated debate that laid bare the U.K.'s bitter ideological divisions, Johnson was forced to wait for the big Brexit moment on which he has staked his political career.

Opening the debate Saturday, Johnson urged lawmakers to approve what he called "a deal that can heal the rift in British politics, unite the warring instincts in us all." JESSICA TAYLOR / AFP - Getty Images

Rather than delivering a decisive yes-no verdict on his deal, the rebels opted for a third route: Withholding final judgment on the deal and forcing Johnson to ask Europe for yet another extension.

They want more time to scrutinize and possibly tweak his plans. They also want to avoid the risk of the U.K. crashing out of the E.U. without a deal at all.

This extreme scenario could cause economic pain, food shortages and even civil unrest, according to expert models and government forecasts.

Delay, but for how long?

Saturday's vote is intended to stave off that outcome.

Lawmakers voted 322 to 306 in favor of the Letwin amendment — named after former Conservative Cabinet member Oliver Letwin, who devised the motion.

He was one of 21 rebels the prime minister fired from the party last month for opposing his hardline plans.

Because of a law passed last month by his opponents, Johnson was forced to write a letter to the E.U. later Saturday asking for yet another extension.

He reluctantly did so, despite repeatedly claiming he would not.

The extension request has just arrived. I will now start consulting EU leaders on how to react. #Brexit — Donald Tusk (@eucopresident) October 19, 2019

Despite the setback, the prime minister remained defiant.

British media said Johnson made it clear in the correspondence that he personally opposes an extension.

Speaking in Parliament earlier Saturday, he vowed to stand by his promise to deliver Brexit at the end of the month and said he was not “daunted or dismayed” by the result.

“I will not negotiate a delay with the E.U. and neither does the law compel me to do so,” the prime minister added.

The government said after losing the vote that it would try to pass its deal again on Monday.

Whatever the ultimate outcome, Saturday was the latest evidence of a country at odds over what type of Brexit it wants to deliver, or whether it wants to deliver Brexit at all.

Throughout hours of televised debate, lawmakers set out competing visions of the country at this pivotal moment; whether it should keep close to the environmental and employment protections guaranteed by the E.U., or go down a path of deregulation and free trade made possible by Johnson's hardline Brexit deal.

Outside the House of Commons tens of thousands of anti-Brexit protesters marched through the streets of central London.

Many polls suggest that public opinion on Brexit may have flipped, with a narrow majority now favoring staying inside the E.U.

Brexit has seen politicians resort to increasingly violent language when describing their opponents, leading police to warn them not to inflame what has become a febrile atmosphere in the country.

Many members of Parliament — mostly women — have received death threats referencing their views on Europe.

One female lawmaker was murdered in 2016 and another was the subject of a foiled far-right plot to kill her.

On Saturday prominent opposition Labour Party lawmaker Diane Abbott was forced to have a police escort as she left Parliament, with at least one person seen verbally accosting her. Jacob Rees-Mogg, a key Johnson ally and vocal Brexit advocate, was also guarded by law enforcement as a pro-E.U. crowd chanted "shame on you."

These fierce divisions show no signs of abating, and the fate of Brexit itself remains uncertain.

Saturday's delay means the door is still open for a host of other options beyond Johnson's deal, including an early general election or even a second referendum.

The prime minister's plan seeks to scrap all of the major trading rules that currently bind the U.K. to the E.U. But it will keep some of these ties in Northern Ireland.

This is an attempt to avoid a "hard border" being created with the Irish Republic, which is a separate country and will remain part of the E.U. after Brexit.

Many fear any kind of Irish border would see a return to sectarian violence that plagued the region until a peace deal in 1998.