This is really about whether there will be a change of Prime Minister ahead of the next general election which of course is due to take place in 2024. The greater it seems likely that there will be no change at the top in the Tory Party the greater the chances punters will see of Starmer being the next PM
Starmer’s price would drop sharply I would suggest if it becomes clear that Johnson might face a leadership challenge – the first stage of which would be a petition by Conservative MP’s to have a confidence vote on him. As we all no doubt know the total of MPs backing this move has to be 54 or more.
So the more Johnson appears secure in his job the higher the probability of Starmer being his successor as PM.
As I have noted before a point of real danger could be the two by-elections due to take place on June 23rd. The betting markets currently rate Conservative defeats in both of them as a very high chance.