LONDON (Reuters) - Boris Johnson will send a letter on Saturday requesting a further extension to Britain’s departure from the European Union, an EU official said, with the British prime minister obliged to ask for a delay after losing a vote in parliament.

Johnson had hoped that Saturday would see recalcitrant lawmakers support the divorce deal he agreed with EU leaders this week and finally end three years of political deadlock since the 2016 referendum vote to leave the bloc.

Instead, lawmakers voted 322 to 306 in favour of an amendment that turned Johnson’s planned finale on its head by leaving the prime minister exposed to a humiliating obligation to ask the EU for a delay until the end of January 2020, and increasing the opportunity for opponents to frustrate Brexit.

Graphic: British lawmakers switching sides (here)

Johnson has been promising that he will take the country out of the bloc on Oct. 31, come what may, and after the amendment passed, he struck a defiant tone.

“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.”

However, he appeared to acknowledge in a letter sent later to lawmakers that he would ask for a Brexit extension - as called by for an earlier law passed by his opponents.

“It is quite possible that our friends in the European Union will reject parliament’s request for further delay (or not take a decision quickly),” Johnson wrote.

European Council President Donald Tusk said he had spoken to Johnson and an EU official said Johnson had confirmed in that call that the letter asking the EU for an extension would indeed be sent.

“Tusk will on that basis start consulting EU leaders on how to react. This may take a few days,” the official said.

The deadline for the letter to be sent appeared to be 2300 GMT on Saturday: the law itself referred to 11 p.m. without saying what time zone, but the text of the letter Johnson is meant to send refers to a deadline of 11 p.m. GMT.

Graphic: Understanding Brexit (here)

DEMONSTRATIONS

Saturday’s amendment, put forward by former Conservative cabinet minister Oliver Letwin, deflated Johnson’s big Brexit day just as hundreds of thousands gathered to march on parliament demanding another referendum on EU membership.

After several hours of heated debate, senior politicians - including Business Secretary Andrea Leadsom, House of Commons leader Jacob Rees-Mogg and Labour’s foreign affairs spokeswoman Diane Abbott - were escorted from parliament past jeering demonstrators by phalanxes of police.

The European Commission said Britain must now inform it of its next steps as soon as possible. French President Emmanuel Macron told Johnson a delay was in no-one’s interest, an official at the French presidency told Reuters.

Ireland believes granting an extension is preferable to Britain leaving with no deal, but there is no guarantee that view is shared throughout the EU, its foreign minister said.

But however weary EU leaders are of the long and tortuous road to Brexit, it seems likely that the bloc will grant a delay.

Graphic: Understanding the Irish border (here)

BREXIT DELAY?

In a move designed to prevent the United Kingdom slipping out of the EU without a deal by design or default, Letwin’s amendment delays parliament’s ultimate decision on Johnson’s Brexit deal until the very end of the process.

Slideshow ( 13 images )

By supporting Letwin, whom Johnson had expelled from the Conservative Party, parliament exposed the prime minister to another law passed by his opponents that called for him to ask for a delay until Jan. 31, 2020 unless he had a deal approved by the end of Saturday.

Even if he is given an extension that he does not want by the EU, Johnson could still take the country out of the bloc on Oct. 31 because the law allows him to if he can get all the legislation approved by that date.

Rees-Mogg said the government now planned to put Johnson’s withdrawal deal to a debate and vote on Monday, but the house speaker John Bercow said he would rule on Monday whether he would allow that.

Letwin said he hoped Johnson’s deal would succeed, but he wanted “an insurance policy which prevents the UK from crashing out on 31 October by mistake if something goes wrong during the passage of the implementing legislation”.

Three years after the country voted 52%-48% to leave the European project, many Britons say they are bored with the whole Brexit argument and just want the process to end.

Slideshow ( 13 images )

But others demonstrating on Saturday remain angry that Britain is leaving the EU and want that reversed.

Hannah Barton, 56, a cider maker from Derbyshire in central England, was draped in the EU flag. “We feel that we are voiceless. This is a national disaster waiting to happen and it is going to destroy the economy,” she said.

Jeremy Corbyn, leader of the main opposition Labour Party, backed a second referendum, saying “the people should have the final say”.

Protesters outside parliament cheered as lawmakers backed Letwin’s amendment.

‘SUPER SATURDAY’

Brexit “Super Saturday” topped a frenetic week that saw Johnson confound his opponents by clinching a new Brexit deal with the EU.

When it comes to a vote in a divided parliament where he has no majority, Johnson must win the support of 320 lawmakers to pass his deal.

If he wins, he will go down in history as the leader who delivered a Brexit - for good or bad - that pulls the United Kingdom far out of the EU’s orbit. Should he fail, Johnson will face the humiliation of Brexit unravelling.

He says lawmakers face the option of either approving the deal or propelling the United Kingdom to a disorderly no-deal exit that could divide the West, hurt global growth and bring renewed violence to Northern Ireland.

To win, Johnson must persuade enough Brexit-supporting rebels in both his Conservative Party and the Labour Party to back his deal. His Northern Irish allies and the three main opposition parties oppose it.

Graphic: Brexit’s ‘Super Saturday’ (here)