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 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. 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.

  2. Paul O’Connor

    That’s a lot of work, well done.

  3. 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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