British Prime Minister Boris Johnson's dream of leaving the EU on 31 October with a Brexit deal has been dealt a serious blow, and he has told MPs he will now "pause" the Withdrawal Agreement Bill.
So, what does this mean and what happens now?
What is the Withdrawal Agreement Bill (WAB)?
The WAB is the British government's Brexit Bill, the legislation needed for Brexit, which would implement the new deal agreed with the EU in UK law.
Do MPs support it?
MPs voted by 329 votes to 299, majority 30, to approve the Bill in principle, the first time the Commons has been prepared to back any Brexit deal put before it.
That sounds like progress. Will the WAB now move to the next stage of the parliamentary process?
No. Because even though MPs voted in favour of the Bill, they voted by 322 to 308 to reject Mr Johnson's plan to take the legislation through the Commons in just three days.
Mr Johnson told MPs he would "pause" the WAB until the EU takes a decision on whether to grant another Brexit delay.
How did the EU react to the development?
A spokeswoman for European Commission said they have taken note of the result and "expects the UK government to inform us about the next steps".
European Council President Donald Tusk later said he will recommend the EU accept the UK's request for a Brexit extension.
Do MPs just want more time to study the WAB?
There is a desire for more time to scrutinise the legislation, yes. SNP MP Joanna Cherry QC said the programme motion was "frankly ludicrous for such complex legislation".
Labour leader Jeremy Corbyn has offered to work with the government to agree a "reasonable timetable" for the WAB.
Mr Corbyn said this would be a "sensible" way forward. Time will tell as to whether the prime minister agrees.
Could there be an extension?
Under the terms of the Benn Act, which was passed against the PM's wishes, the prime minister was compelled to write to the EU asking for a three-month Brexit extension if he had not secured a deal by 11pm UK time on 19 October.
He told the Commons: "I will not negotiate a delay with the EU, and neither does the law compel me to do so."
But he did send two letters to European Council President Donald Tusk.
First, there was an unsigned photocopy of the request he was obliged to send under the Benn Act, followed by a letter explaining why the government did not actually want an extension.
The EU has yet to take a decision on whether to grant another delay, but European Council President Donald Tusk said he will recommend the EU27 accept the UK request for an extension.
There is also talk in Westminster of a technical extension to allow the UK to leave the EU once the Bill has passed.
The EU could go for the three months requested by Mr Johnson, but it may kick the can much further down the road: six months or even a year could be on the cards if the EU decides it wants to move on with its own affairs and give Britain space to sort itself out.
A longer postponement might be possible if it was clear that either a general election or a new referendum was at hand.
However, a deadline for the EU is shaping around its next long-term budget from 2021, which will hang on whether Britain is staying or leaving. Some EU diplomats and officials say this means Britain must be in or out by the middle of next year.
Will there be a general election?
All the main party leaders have said they want one but they wanted to make sure Mr Johnson would not carry out a no-deal Brexit on 31 October.
The opposition has insisted it wants to ensure a Brexit extension before agreeing to a poll.
Labour's Brexit spokesperson Keir Starmer has said that a snap election would be "inevitable" if EU withdrawal is delayed.
Mr Corbyn has said they have to be "absolutely clear" that there will be an extension and no crashing out of the EU.
How could the government call an election?
The government could table a motion under the Fixed-term Parliaments Act, but this would require a two thirds majority.
Or, they could table a one-line bill.
If opposition MPs refuse to back any government moves to force an election, Mr Johnson may make the extraordinary decision to trigger a confidence motion in his own administration.
Will the UK leave the EU on 31 October?
The Prime Minister has pledged to take Britain out of the EU by the Halloween deadline "do or die".
He told MPs last night that he would consult with other EU leaders on what should happen next.
Even if Mr Johnson gets his deal through the House of Commons in the coming days, it would still have to be approved by the European Parliament, which is sitting this week but not next.
An extraordinary session of the EU assembly could be called, but an EU official said that MEPs will want time to scrutinise what is a very complex agreement and some will "smell an opportunity" to slam the brakes on Brexit.
As it stands, it looks unlikely that Brexit will happen on Mr Johnson's preferred date.
Additional reporting Reuters