I have been making flow diagrams since January 2019. Series 1 was more my effort to get to grips with this diagramming lark. Series 2 was the first with probabilities, and predicted a Brexit delay – and that’s what happened. Series 3 started after the European Elections in May 2019 predicted that a General Election would be the next outcome – and that was right too. A little more detail about how I make the diagrams is here.

So now it’s time for Series 4 – what impact will the 12th December 2019 UK General Election have on Brexit outcomes?

This series is harder than the others, as I am not a pollster. Predicting how 600-odd MPs will vote, or 27 Member States of the EU will behave, is easier than working out how 40 million Brits will vote! So this diagram has to draw on different data from the previous diagram series. Version 1 uses Betfair Exchange data to work out the probability of different numbers of seats for the Tory Party, and these are then put into the diagram. Future diagrams might use different statistical sources as the General Election campaign develops.

Why is the number of Tory seats so central to the new series?

Because we are pretty sure that no other party is going to want to go into a coalition with them or even support them, post election, due to their position on Brexit. I make the judgement that 320 or more MPs for the Tories will be enough for them to govern and get the Withdrawal Agreement Bill through. Were the Tories to gain just 289 seats, that would leave the combined opposition of Lib Dems, SNP, Plaid Cymru, Greens and Independents on about 324 – probably enough to see a minority Labour administration through until a 2nd referendum could be held. The problem of course is results in between these two – the implications of these are covered in the diagrams. I assume 8 Sinn Fein and 10 DUP MPs elected in Northern Ireland – figures are calculated accordingly.

I am also introducing a stricter version system for this series. Diagrams will be V x.y.z – changes to z will be only to correct typos or add notes. Changes to y will be changes to probabilities. Changes to x will be new routes or outcomes on the diagram, or changes to the working method used. All times are CET.

IMPORTANT: while each and every iteration of the diagram will be listed here, all the high resolution PNG images, scaleable PDFs, the .ODS file for my workings, and the draw.io XML for the diagram will be uploaded to this folder.


Version 3.0.0 – 10.12.2019, 1315
Betting markets stable regarding a Conservative victory, some slight move from a stalemate situation towards a hung Parliament.


Version 2.3.0 – 22.11.2019, 1000
Betting markets leaning more heavily towards a Conservative victory.


Version 2.2.0 – 14.11.2019, 1200
Farage has announced the Brexit Party will not be running in the 317 constituencies won by the Conservatives in 2017. This has pushed the Betfair Exchange odds further towards a Conservative majority, and this is reflected in this diagram.


Version 2.1.0 – 10.11.2019, 1800
Some changes to the Betfair Exchange odds over the past 48 hours – now fed into the diagram. Betfair seems to see the chances of the Tories winning big increasing.


Version 2.0.0 – 8.11.2019, 1815
There was an error in my calculation method for V1.0.0 and V1.1.0 as explained here. Now corrected in this version!


Version 1.1.0 – 7.11.2019, 2200
Betfair data updated. Chances of a workable Tory majority slipping slightly.


Version 1.0.0 – 6.11.2019, 1300
The first of the new series. Uses Betfair Market data.

One Comment

  1. Pingback: Jon Worth on who to follow and where to focus - John Harper Publishing

Leave a Comment

Your email address will not be published. Required fields are marked *