The battle to replace Theresa May as leader of the Conservative party – and become the next Prime Minister – will be the largest in history.
Since party rules were amended in 1964 to allow leadership contests there have been 10 such events, which we’ve analysed to identify the most common ingredients to a successful challenge.
This year’s race is already the first to have a double-digit number of runners, which should provide plenty of opportunities for anyone looking to place a bet from the next Prime Minister odds.
Does a candidate’s experience matter?
In terms of age there is definitely a sweet spot for being elected leader, with half of the 10 previous winners all falling in a narrow band from 47 to 52. This might count against the favourite in the next Prime Minister betting which is 54-year-old Boris Johnson, with candidates over 52 having a poor collective record of just three successes from 21 entries.
Where Johnson fares better is in having held the post of Foreign Secretary, which has produced a winner before: former incumbent John Major won two leadership contests in the 1990s.
The fact that he resigned from Theresa May’s government takes the shine off this association though, as all five previous leadership candidates who did so were defeated.
How much influence does a candidate’s seat have?
Sticking with our theme of casting doubt on the favourite, Boris Johnson also compared unfavourably to the rest of the field when we looked at how safe each candidate’s seat was. With a majority of just 10.8% at the 2017 general election, Johnson is arguably vulnerable to being unseated if the national mood continues to sour against the Tories.
The smallest previous majority secured by either a sitting or newly-elected Prime Minister was Edward Heath’s 15.8% in 1965, so if a general election were to follow then Johnson would have a historically low electoral buffer. All of the other next Prime Minister candidates except Mark Harper have a majority north of 30% and would be far tougher for another party to depose.
To end on a positive for Johnson, representing a seat in London gives him an edge in the battle to be the next Prime Minister, with four of the eight previous candidates to have contested a leadership election from a London seat having prevailed. He’d be following in the footsteps of Edward Heath, Iain Duncan Smith and Margaret Thatcher (twice), who all secured the top job while being based in the capital.
How do the next Prime Minister candidates compare on social media?
A relatively new dimension to political contests is the candidates’ social media presence, with much being made of the need for the Conservatives to secure the support of a younger generation of voters.
Boris Johnson is by far the most-followed candidate on Twitter but he’s been one of the least active since joining the platform in 2015, averaging just over a tweet per day. The likes of Matt Hancock, Michael Gove and Rory Stewart have far fewer followers but have each sent over three tweets per day on average and could therefore be more accessible to younger adults active on social media.
Next Prime Minister contenders: The top three
We’ve assigned a score to each candidate for each dimension of our analysis and averaged these to estimate who has the best chance of securing the top job. Three names emerge slightly higher than Boris Johnson in our list: Michael Gove, Jeremy Hunt and Matt Hancock should all be considered as credible challengers.
Gove’s age, majority and location count in his favour and he has held senior posts which have previously been a path to the leadership, with only his previous failure in 2016 counting against him.
Hunt has similar advantages but no former Health Secretary has ever triumphed in one of these contests, which also undermines Hancock’s chances despite his active Twitter presence.