• Boris Johnson must agree a deal with the EU at this week’s EU summit on Thursday – if he is not to return on Friday, face the Commons on Saturday, and be asked how, despite the Benn Act, he intends to achieve Brexit by October 31.
  • If he agrees a deal, he will need, first and foremost, to square the DUP – since its most contentious element in Parliament will concern Northern Ireland.
  • If he can get the DUP to support him, he will then need to win the backing of the Spartans.  They have concerns not only about Northern Ireland but about the Withdrawal Agreement as a whole.  To date, Steve Baker, speaking on behalf of the ERG, is keeping his counsel.
  • At the same time as keeping the Spartans on board, the Prime Minister will need to win the backing of as many of the whipless 21 former Tory MPs as he can.  Some oppose a No Deal Brexit.  Others oppose Brexit outright.  (For example, this seems to be the position of Guto Bebb.)  How they divide up could be crucial if there is a vote.
  • Whether there is slippage among the Spartans and support among the 21 or not, Johnson may also be reliant on Labour MPs.  A group of 19 may vote with him, including Dan Jarvis, Caroline Flint, Sarah Peacock and Melanie Onn.  Nonetheless, Theresa May was always angling for similar support at the crunch. None came.
  • The most solid prospects from Labour look to be Kate Hoey and John Mann. The Prime Minister will be lobbying too for support from the 35 independent MPs who are unaligned to any group.  He would probably win a majority of these – but by no means an overwhelming one.
  • Then there is the prospect of vote on a second EU referendum next weekend – which Keir Starmer and Tory Remainers alike will push for.
  • Our best guess is that the numbers will not be there for a referendum in the event of a deal, but could be if there is No Deal.  How many of the 21 want to stop a No Deal Brexit – and how many to stop Brexit altogether? A referendum vote next weekend would tell us.
  • Next, there is a timetable question.  Can the Prime Minister really agree and finalise a deal, and then get a Bill based on it through the Commons before October 31?  Watch for him proposing an extension.  Or Philip Hammond and others seeking to force one on him.  And remember: the Speaker will play a crucial role in any proceedings.
  • Whether there’s an extension or not, Johnson will need the DUP, the Spartans, some of the 21 and some Labour MPs not only for any votes next weekend, but for those on any Bill which seeks to implement his deal.  It isn’t just next Saturday that could be a nightmare for the Conservative Whips.