And then there were two: Boris Johnson will take on Jeremy Hunt in the final round of the Conservative leadership contest, after the Foreign Secretary narrowly pipped Michael Gove to reclaim second place in the fifth ballot of Tory MPs yesterday.

Gove, who led the chasing pack in the fourth round, lost by a mere two votes, with 75 to Hunt's 77. Boris Johnson, meanwhile, saw his total increase by just three votes to 160 — despite five supporters of the eliminated Sajid Javid publicly declaring their backing for him.

This morning's papers conclude that Gavin Williamson, the former chief whip now acting as Johnson's parliamentary enforcer, encouraged tactical voting to manipulate those numbers to the Gove's disadvantage.

So did Team Johnson really swing the result in order to secure their favoured opponent and exact revenge on the Environment Secretary? In truth, it doesn't really matter. The working matters less than the answer: Johnson, barring some unforeseen catastrophe, is overwhelmingly likely to win the membership at a canter.

The feeling in Johnson's camp is that fighting an emollient Hunt, rather than the pugnacious Gove, as good as guarantees a much bigger margin of victory. Despite winning the votes of more than half of all Tory MPs yesterday, it remains the case that 49 per cent of the parliamentary party did not back Johnson even after his victory became a racing certainty. Imposing authority on a party so divided will be a big ask, and allies of the frontrunner believe only a huge mandate from the grassroots will do it.

But much more important than any of this are the numbers Johnson, Williamson or Grant Shapps' magic spreadsheet won't be able to control once their man reaches Downing Street. Opponents of no-deal on the Tory benches are now so radicalised that 27 of them backed the kamikaze candidacy of Rory Stewart. The hardest Brexiteers, nearly all of whom are backing Johnson, remain implacable.

Nobody has yet provided a convincing answer of how exactly any Tory prime minister will achieve anything, let alone push through a no-deal Brexit, with a terminally divided party and a working majority of five. If voters in Brecon and Radnorshire recall their Tory MP today, then Johnson's time in office is likely to begin with a by-election defeat to the Liberal Democrats that reduces it to two. And that's before you consider the fate of the minister caught manhandling a young female protester in his marginal constituency last night.

The inconvenient truth for Johnson is that these are the numbers that will make or break his premiership. And unlike Gove's vote tally, there is no way he can manipulate them without calling or blundering into the general election he has promised Conservative MPs will not happen this side of Brexit. He might as well promise that it won't rain.