The PM is widely expected to be defeated again in a vote on whether to have a snap general election in mid-October, and his reaction to that could prove key this week.
He is currently scheduled to prorogue parliament on Tuesday, but could delay it until the end of the week if he wants to make a fresh attempt at calling an election.
If he does, he will have to convince Labour or other opposition parties that no-deal Brexit is off the table on October 31, and that the date of any election cannot be moved to after the withdrawal deadline by the government.
So instead of offering a vote under the Fixed Term Parliaments Act, which requires a two-thirds majority, he may seek to bring forward legislation which locks in the date and only needs a simple majority of MPs.
As one Labour source says, that is fraught with danger as MPs will be able to hang on it all kinds of amendments.
Plus opposition parties will have even less trust in the PM after Dominic Raab on Sunday suggested the government could try and bypass the anti-no deal legislation which passed through parliament last week by finding a legal loophole in it.
But HuffPost UK understands that Labour is still not ruling out backing an election this week, if some kind of mechanism can be found to bind Johnson’s hands on no deal.
If it cannot, Johnson may choose to go ahead with prorogation, catch breath, and come back to fight another day.
If he does choose to suspend parliament, the Hilary Benn anti-no deal bill should get royal assent and become law, but again opposition MPs will be watching the government like hawks to ensure the convention is upheld.