Prime Minister Boris Johnson has sent an unsigned letter to the European Union requesting a delay to Britain's exit from the bloc, as well as a second note saying he did not want a "deeply corrosive" Brexit extension.
Johnson was required by law to send the first letter, after parliament voted on Saturday to withhold its approval of his Brexit deal until it has passed legislation to formally ratify the agreement.
Following is a rough guide to what could happen next:
Monday: Possible Brexit deal debate
Jacob Rees-Mogg, leader of the lower house of parliament, or House of Commons, said on Saturday the government planned to put Johnson's exit deal to a debate and vote on Monday.
But the speaker of the House, John Bercow, said he would rule whether that would be allowed after several lawmakers said it would break with parliamentary convention that the same question cannot be put twice during the same session.
"I have been blindsided on this matter, as others have been," Bercow told parliament after Rees-Mogg's announcement.
"I will reflect on the matter, absorbing what colleagues say and consulting others for their advice, and I will report to the House on Monday," he added. "The government are not the arbiter of what is orderly."
Monday: Scottish court hearing
Scotland's highest court, the Court of Session, is due to consider on Monday a legal challenge that sought to force Johnson to comply with the so-called Benn Act. That was the law which required him to write the extension letter if parliament had not approved either a deal or a no-deal exit by Oct. 19.
Anti-Brexit campaigners had asked the court earlier this month for it either to issue an order forcing Johnson to ask for a delay or for it to instruct that a letter be sent to the EU on his behalf if he refused.
The campaigners also said he should face penalties including a fine or even prison if he did not comply with the Benn Act.
The court, has not yet ruled on the matter and was waiting to do so pending developments up to Oct. 19. But it said this month that government lawyers had given formal legal statements - averments - that he would abide by the Benn Act and it would be a serious matter if he did not.
"It would be destructive of one of the core principles of constitutional propriety and of the mutual trust that is the bedrock of the relationship between the court and the crown for the prime minister or the government to renege on what they have assured the court that the prime minister intends to do," judge Paul Cullen, known as Lord Pentland, said.
Opposition lawmakers said that by writing two letters, Johnson had broken his government's pledge to the court not to frustrate the legislation.
"He may well be in contempt of parliament or the courts themselves because he's clearly trying to undermine the first letter," Labour's finance spokesman John McDonnell told Sky News.
Labour's Brexit spokesman Keir Starmer told BBC television Johnson was "being childlike", adding "I am sure there will be court proceedings".
Tuesday? Brexit legislation
Johnson told parliament that "next week the government will introduce the legislation needed for us to leave the EU with our new deal on October 31". It is widely expected to have its first main stage of debate on Tuesday.
Senior minister Michael Gove said on Sunday the government would seek to get the legislation required through parliament in order to get Brexit done and leave the EU on Oct. 31. Gove and foreign minister Dominic Raab said they believed the government had the numbers to pass a deal.
Former minister Amber Rudd, who quit the government over Johnson's willingness to pursue a no-deal Brexit, said she and most of the 21 Conservative lawmakers who were kicked out of the parliamentary party for backing attempts to block a no-deal exit, would support the legislation.
"He has a fragile but sincere coalition of people who want to support it," she told Sky News.
Lawmakers will have the opportunity to bring changes to the legislation and Labour's Starmer and McDonnell said on Sunday the party would put forward amendments including on issues such as protecting worker's rights and closing the "trap door" to a no-deal Brexit at the end of a transition period in December 2020.
Changes proposed by lawmakers are also likely to include the need for a confirmatory referendum on the agreement. That would throw open the possibility of Brexit not even happening - although it is not clear whether there would be sufficient numbers among lawmakers to back such a plan.
EU response to delay request
The chairman of European Union leaders, Donald Tusk, said on Saturday he had received the extension request and he would now be consulting with EU capitals on how to react.
After a short meeting on Sunday, diplomats with the bloc said the EU would play for time rather than rush to decide on the delay request.
"We're looking for more clarity towards the end of the week, hoping that by that time we will also see how things develop in London," one senior EU diplomat said.
Leaders of the 27 states that will make up the EU once Britain leaves are unlikely to deny the extension request.
Gove said the EU was "waiting to see what parliament does now".
"We'll have an opportunity in the days ahead to consider the legislation that allows us to leave the European Union. If people vote for that legislation (..) then we can leave and we can leave in time," he said.
Both the governing Conservatives and main opposition Labour Party say they want a new election, but Labour leader Jeremy Corbyn has said he will not back any move to hold one until a no-deal Brexit is ruled out.
"An election is inevitable because of the numbers in parliament, because we have got to break the impasse, the timing will be a matter for Jeremy Corbyn ... but it is inevitable that sooner or later this breaks into a general election," said Starmer.