Tory hopefuls are frantically lobbying MPs today with just hours to go until voting begins to decide the next PM.
Half the 10 candidates could be wiped out at a single stroke in the first round of the contest - as they need at least 17 backers to continue.
Boris Johnson cemented his status as the front runner to replace Theresa May as a poll found he is the overwhelming choice of members.
The survey by the grass-roots ConservativeHome website put him on 54 per cent - with Rory Stewart a surprising but distant second on 12 per cent.
Launching his campaign yesterday, Mr Johnson warned of 'mortal retribution' from the public unless the government delivers Brexit - although he was left blustering by questions over whether he used cocaine in the past.
At a hustings last night, he also refused to rule out suspending Parliament to force No Deal by the end of October, merely saying he was 'not attracted' to the idea.
But rivals have stepped up their attacks on the former foreign secretary, with Home Secretary Sajid Javid branding him one of the 'same old school ties' and urging Conservatives to choose a less divisive candidate.
Foreign Secretary Jeremy Hunt joked that he woke up today feeling like it was the 'morning of my wedding'. 'Something big is going to change but don't quite know how it is going to unfold,' he tweeted.
Boris Johnson (pictured leaving his London home today) cemented his front runner status yesterday after launching his leadership campaign
Michael Gove (pictured leaving his London home today) has been struggling to recover after admitting to cocaine use in the past
Foreign Secretary Jeremy Hunt joked that he woke up today feeling like it was the 'morning of my wedding'
Ten MPs are on the ballot as Tory MPs prepare to vote on who will be their next leader
Leadership hopefuls need at least 17 votes in the secret ballot to go through to the second round, with anyone below the threshold automatically eliminated.
But even if all the candidates meet the target, the one with the lowest number of votes overall will still have to exit the race.
Mr Johnson has 82 public pledges of support - way ahead of Michael Gove who has 32, and Jeremy Hunt on 30. Dominic Raab has 22, and Sajid Javid 18.
Health Secretary Matt Hancock looks to be close to the threshold of 17, while all the other candidates are well below on declared support.
However, dozens of MPs have yet to state their allegiance - and it is a secret ballot so there is no way of knowing whether they follow through on their pledges.
This will be another critical day, as the first ballot takes place between 10am and noon. The result is due to be announced at 1pm.
Anyone with fewer than 16 votes will be automatically eliminated, and at least one will be ejected.
THURSDAY, JUNE 19
Further rounds of voting will take place during June until there are just two candidates left by this point.
They will then go to a run-off ballot of the 160,000 Tory members.
WEEK OF JULY 22
The winner is due to be