After the success of my two previous series of Brexit diagrams (5 diagrams in series 1 in January, 26 diagrams in series 2 between February and April) I took a little pause for a month after the decision was taken on 10 April 2019 to delay Brexit until 31 October 2019. I even told the New York Times I might stop making these diagrams

But due to popular demand the diagrams are back!

This new series of diagrams tries to plot what will happen on the UK side primarily between May 2019 and the new Brexit deadline in October.

For each diagram 4 documents will be produced:
– the XML file
– a high resolution PNG file
– a scaleable PDF file
– the .ods file I use to calculate the odds

All of these documents will be uploaded to this folder each time – so please check there for the latest versions! Images will also be added to this blog post below, with the newest diagrams at the top.

Version numbers will change if the options on a diagram change. If only probabilities change, or minor spelling corrections are made, this will be a .x version.

As ever these diagrams are made based on how MPs have voted in the past, and using opinion polls as a means to predict how MPs and Tory activists will behave in the future. All of this needs some educated guessing. However the previous diagrams long predicted a Brexit delay as the most likely outcome, and that was what happened – so maybe there is some use to this!

Version 10.3 – 21.8.2019, 1330
George Peretz pointed out that I was missing a route – from legislative efforts to block No Deal succeeding through to a General Election by Johnson calling for an election. This has been added to the bottom right of the diagram, and necessitated some further redesign work.


Version 10.2 – 21.8.2019, 1230
Changes to odds in light of tactical observations on Twitter from Paul Mason. And some design changes too, to make it clearer that there can be earlier or later VONC routes.


Version 10.1 – 20.8.2019, 2200
There were two main reactions to version 10 – why is crashing out during an election campaign not accounted for (note added here), and will the EU grant a further extension? Both of those, and some minor design changes, are now in Version 10.1


Version 10 – 20.8.2019, 1200
OK, so I am back from 3 weeks of holiday, and have tried to get my head around what’s happening now – the Yellowhammer leak, stuttering efforts to get a caretaker government to be formed by Corbyn, but his rather categoric statements that a Vote of No Confidence will happen in September. All of this adds up to the chances of a General Election dropping a bit, and the chances that the UK can agree to nothing other than opposing No Deal increasing quite a lot. For the first time some detail of how at least a first VONC would go is added here.


Version 9 – 26.7.2019, 1430
Johnson managed to see his way through his first week. And we have some more idea what he might try to do now, and how the House of Commons will most likely seek to stop him. This is all reflected in the latest diagram – and this will be the last one until 19th August unless something major happens in the meantime. I need 🏝


Version 8 – 23.7.2019, 1700 BST (note times were CET on previous versions!)
So Boris Johnson has been appointed. I have now added what will happen in the days after his appointment to the overall picture. Also I had previously gone along with the UCL Constitution Unit blog’s conclusions re. Johnson and a majority, while here I have switched to this interpretation from Carl Gardner and others (0.8 probability) – all of that has negligible overall impact, but increases the chance of a General Election in the autumn rather than starting to plan for one now.


Version 7.1 – 11.7.2019, 1130
Now assuming Johnson will win (based on this by Political Betting), and drawing on this about No Confidence scenarios by the UCL Constitution Unit, and with more detail on timing from this by Jonathan Lis. There is a whole new section – to try to work out what happens if a PM Johnson cannot command the confidence of the House of Commons – but that ultimately does not make much difference to the overall probabilities – still at 66% chance of a General Election. The only question is whether that is called sooner or later. Also note that the .ods file uploaded to this folder has a new structure – you can change each node within it now, and see how that changes the overall probabilities.


Version 6 – 27.6.2019, 1130
Johnson is strengthening his position. But what happens were each of them to win? Three diagrams for that!

Version 6 – 25.6.2019, 1730
The final two are known – Johnson and Hunt. And Johnson has started to struggle. All on the latest diagram!

Version 5 – 13.6.2019, 1200
Tory MPs vote in the first round, with Johnson pulling ahead. This change is added to the diagram, but makes little difference to the overall outcome.

Version 4 – 9.6.2019, 1200
This is based on growing parliamentary support for Boris Johnson, notably from Brexit hardliner Steve Baker. It also increases the odds that a hardliner that isn’t Boris would lose a majority. The impact of this on the overall outcome? Just +/- 1% compared to version 3!

Version 3 – 27.5.2019, 1900
Some additional routes proposed by Twitter users @wrexit and @susan04071 and added here.

Version 2.2 – 27.5.2019, 1215
Probabilities adjusted based on reactions to the aftermath of the European Parliament elections in the UK. Paths in the diagram unchanged.

Version 2.1 – 25.5.2019, 1945
After Theresa May’s statement resigning as PM, and building on the betting about the Tory Leadership election and the announced procedure as to how that will work. (Version 2 had an error – the .ods was right, but I had put 26% rather than 23% for No Deal)

Version 1 – 22.5.2019, 1600
Published after Theresa May’s statement on 21.5, outlining her plan to get the Withdrawal Agreement Bill through the Commons (essentially a 4th try to get her Brexit Deal approved). This was produced while rumours of May’s imminent demise is circulating but no news is confirmed.


  1. Fascinating.

    I think the biggest fear though is that the (seemingly inevitable) general election is timed in such a way that MPs dont have the time to pass emergency legislation, though.

    Tories always fall in line, regardless of right or wrong or national interest (see Rudd, Amber). If BJ calls a General election for 31st October (with new Govt to be appointed in the early hours of 1st November, after the deadline), Brexit party supporters will flock home to the Tories and they will win a majority. Polls will show this as soon as he calls it, and any Tory tempted to vote against their own government / vote for an extension or whatever else will just consider Brexit and the damage it will cause a small price to pay to get a Tory government and keep Corbyn out of #10.

    I’m not sure its as clear as your diagram suggests that it would be that easy for the Commons to squeeze through Wash-up legislation requesting an emergency extension to prevent no deal. You have that as a 100% chance if it gets to that, and i’m struggling to see it.

  2. Thanks for this, even if it’s not necessarily what we want to hear!

  3. That One Girl People Aren't Sure About

    These look like the plumbing in my old apartment building.

  4. Pingback: And the New Leader of the Tory Party is: Boris Johnson – Progressive Pulse

  5. Wanted to drop a quick note that the effort you put into this, is noticed and really appreciated.

  6. Brilliant work.

    Just one quibble: since “no deal” is the default, come October 31, could we not crash out regardless of a general election or referendum? So it is possible (I hope not likely!) to have both.

    • Rosalind Stewart

      Patrick, it seems clear from the experiences of both 29 March and 12 April that Parliament would have to pass a No Deal Brexit. This has been confirmed by constitutional experts at the Constitution Unit at UCL and elsewhere. I have also heard experts in Brussels saying that they are already preparing for another extension. So no, crashing out with no deal is not the default.

      And thank you, Jon, as ever, for these insightful diagrams! Personally, I’d put the chances of a second referendum far higher. If I were a Conservative PM, I would reluctantly go for a referendum rather than an early General Election.

  7. Paul O’Connor

    That’s a lot of work, well done.

  8. Stephen Archer

    Excellent Jon

    Keep up the good work. It struck me, in more simple terms, that you can’t be in and out of the Customs Union at the same time. The referendum vote demands OUT the Good Friday Agreement demands IN. Two incompatible outcomes, hence the appalling 585pp document called Chequers, a vain attempt to square the circle.

    • Theodore Welter

      Circling the square is possible if you cheat a little and people cheat all the time. The problem is that Ireland would veto such a cheat because the veto would encourage reunification no matter what happens: If UK revokes it makes the right/DUP/UK nationalists look foolish and weak , if non-Brexit Brexits it silences NI in the EU, Permanent (because Ireland would veto everything) backstop cuts off NI from rest of UK or UK crashes out and annoys NI. There’s a good chance that Boris Johnson goes for circling the square, knowing that Ireland would veto, and use that veto to score free brownie points.

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