Strategists in Downing Street realised on Tuesday afternoon that the government could be heading for defeat on the "programme motion" designed to force Brexit legislation through parliament in just a few days.
At that point they relayed the message to journalists that Boris Johnson would take dramatic action in such circumstances: he would try to force a snap general election. But when the moment came Mr Johnson did nothing of the sort.
Instead he said he would "pause" the bill that would have implemented his deal. The prime minister said that, while he did not want a delay, he would reopen fresh discussions with EU27 leaders on whether or not they would agree one. The ball is therefore now in Brussels' court.
Is October 31 still Brexit day?
Almost certainly not. A Number 10 spokesperson refused to clarify how long an extension would be discussed between the prime minister and EU leaders.
However government aides earlier indicated that Mr Johnson could accept a 10-day delay beyond the "do or die" date of October 31 — so long as it was the very last extension offered by the EU.
The prime minister announced — seconds after the vote — that he would authorise a stepping up of preparations for no-deal Brexit, in case the EU refused to grant any extension at all. "The EU could still choose not to give an extension," Number 10 said.
But that is considered highly improbable, despite warnings from some EU leaders, such as Emmanuel Macron, French president, that they are losing patience with Britain's prevarication.
The question on Tuesday night was therefore how long the EU is likely to offer in its latest extension of Article 50.
According to EU officials, Brussels is likely to offer the UK the extension it has already formally requested to the end of January but with the proviso that it can leave sooner if the withdrawal agreement bill passes through all its legislative stages in parliament.
Downing Street refused to say what length of extension would be discussed by Mr Johnson, saying only: "I can't pre-empt what he's going to say in these calls."
What happens to the Brexit legislation now?
John Bercow, the Speaker, described the bill as "static, but not a corpse", given that it is likely to return before long.
Jacob Rees-Mogg, leader of the Commons, said that MPs will use the rest of this week to debate the recent Queen's Speech. A vote will be held on that on Thursday (UK time).
If, as expected, the EU extends to the end of January but allows the UK to leave sooner if it is ready then talks on the Brexit legislation are likely to resume through the "usual channels" between the different political parties and a new programme is likely to be agreed, giving lawmakers longer to peruse the most important UK legislation in a generation.
Which amendments are now key?
The government still faces potential hurdles in the coming week when MPs put forward various amendments to the withdrawal agreement bill.
One area where some opposition MPs could coalesce against Mr Johnson is an amendment seeking a customs union. This would be designed to force the prime minister to seek a customs union in future negotiations — but not reopen the existing agreement with Brussels — and would therefore be an inconvenience for Downing Street rather than an insurmountable hurdle. But it is unlikely to pass, given the resistance of a phalanx of Labour MPs in Leave seats.
MPs who want a second referendum will try to amend the bill to force what they call a "people's vote" on the final deal, but they are considered less likely to have the numbers to win in the Commons.
Another issue that will come up as an amendment is an attempt to force a guarantee from Number 10 that parliament can mandate the government to seek an extension to the transition after December 2020, a decision that has to be taken by next July. Many business groups are highly concerned that a 14-month transition period is not long enough to ensure stability for their members.
Will there be an election before Christmas?
Number 10 has signalled that if the EU insists on a three month extension — rather than a short technical delay of a few weeks — it will try to trigger a general election instead.
But some senior Tory MPs believe that time is running out for Mr Johnson to try to force a 2019 election, given that it would need a five-week campaign. Strikingly, he did not mention the word "election" in his statement.
Political leaders are generally loath to hold an election in the dark and cold of the winter months, especially close to Christmas.
Questions also remain around whether Labour would vote to allow a snap election later this year, despite claims by Jeremy Corbyn that he is enthusiastic about the idea. Labour is substantially lagging the Conservatives in the opinion polls. But there is little doubt that Labour will have to bow to "inevitability" at some point and agree an election, perhaps in the spring of 2020.
Written by: Jim Pickard and James Blitz
© Financial Times