In what became the Conservative Leadership 2016, Boris Johnson was not, as we know, the winning outcome. Indeed he did not put his name forward as a candidate. The highest Betfair Exchange odds were 55% on the day after the Brexit referendum.
In what became the Prime Minister after Cameron market, Johnson didn’t win yet on the Betfair Exchange next PM market on June 24th 2016 his top price rated his chances at 60%.
In the currently-live market Prime Minister after TMay, Boris Johnson has aggregated betting odds of 7%. This compares with his highest odds of 45% recorded on the day after GE2017.
In the currently-live market Conservative leader after May, Boris Johnson has aggregated betting odds of 7%. His highest odds on Betfair were 34% on June 10th 2017 and the lowest 6% on June 6th this year.
This has not always been the case. He was strong odds on favourite in the London Mayoral contests of 2008 and 2012 which of course he won.
Thank to Betdata.io for the data.