Video report by ITV News Political Editor Robert Peston
Candidates clashed over Brexit escape routes during the BBC Tory leadership debate - the first time Boris Johnson appeared head-to-head against his competitors.
After topping the ballot in another round of voting he faced underdog Rory Stewart, who has positioned himself as the alternative to Mr Johnson's Brexit approach, as well as Jeremy Hunt, Sajid Javid, and Michael Gove.
In the TV debate, mediated by BBC journalist Emily Maitlis, much of the discussion centered around Brexit, with Mr Johnson again calling for a swift exit from the EU.
He said "we must come out" of the European Union on October 31, "otherwise, I'm afraid, we face a catastrophic loss of confidence in politics."
He added: "We have already kicked the can down the road twice and I think the British people are getting thoroughly fed up."
Mr Johnson came well ahead of the rest with 126 votes from Tory colleagues in the contest's second round and former Brexit secretary Dominic Raab was eliminated from the race after failing to secure enough backing to progress.
The results were as follows: Michael Gove, 41 Jeremy Hunt, 46 Sajid Javid, 33 Boris Johnson, 126 Dominic Raab, 30 Rory Stewart: 37.
In the Tuesday night debate, both Jeremy Hunt and Michael Gove said a Brexit delay beyond October 31 may be necessary if a deal was within reach.
Foreign Secretary Mr Hunt said he would walk away without a deal if there was no prospect of agreement by October 31 but "if we were nearly there, then I would take a bit longer".
Mr Gove said he would be prepared to allow "extra time" if a deal was close, adding how he was "upset" and "angry" that Brexit had not yet happened.
"Because I started this, I will finish it," the prominent Brexit-backer said.
Home Secretary Mr Javid said it was "fundamental" to get out of the EU by October 31 and honour the result of the referendum.
In the debate, he said: "We have failed to act on those instructions and it is fundamental that it has to be by October 31."
He told Mr Gove and Mr Hunt: "We have got to learn from our mistakes. One of the mistakes we have made so far is by having this flexible deadline.
"If you don't have a deadline, you don't concentrate minds, and that also includes the minds of our European friends."
Mr Stewart said it would not be possible to negotiate a new deal by October 31, leaving the existing Withdrawal Agreement as the only way out of the EU.
"I would say to all these people on the platform who voted for the deal: take the shock of the European election, let's get on with it, let's vote it through, let's get it done."
He added: "In the end, we're in a room with a door and the door is called Parliament, and I am the only person here trying to find the key to the door.
"Everybody else is staring at the wall shouting 'believe in Britain'."
In a video posted to Twitter after the debate, Mr Stewart said he was "almost the only Brexiteer in the race, in other words I'm the only person that really wants to get this done".
He added that he felt the other candidates were "either pretending they're going to get a new deal out of Europe" or "that they're going to be able to get a no-deal through Parliament".
The group bickered on almost every issue discussed during the debate and the only thing it appeared all five were able to agree on was the need for an investigation into Islamophobia.
In a bizarre moment during the debate Mr Javid asked his colleagues if they'd commit to an external investigation into Islamophobia in the Tory party.
After some shuffling and nodding from his rivals, he said: "It's great that we all agree on that."
Other issues discussed in the debate were tax cuts and offensive comments made by Mr Johnson in the past.
In response to a question on Islamophobia, Mr Johnson said: "When my Muslim great-grandfather came to this country in fear of his life in 1912, he did so because he knew it was a place that was a beacon of hope and of generosity and openness, and a willingness to welcome people from around the world."
Asked about his handling of the Nazanin Zaghari-Ratcliffe case during his time in the Foreign Office, Mr Johnson denied that his erroneous suggestion she had been involved in training journalists had contributed to an increased sentence in an Iranian jail.
"In that case, it didn't, I think, make any difference," he said.
"If you point the finger at the UK, all you are doing is exculpating those who are truly responsible, which is the Iranian Revolutionary Guard."
Following Mr Johnson's comments on Iran, Mr Hunt was asked about his comment's supporting Donald Trump's criticism of Sadiq Khan.
Mr Hunt responded: "What I said was that I agreed with his sentiment that Sadiq Khan has been a useless London mayor when it comes to tacking knife crime."
He denied that he endorsed Trump's retweeting of the "racist rants of Katie Hopkins" about "Londonistan".
He added: "I totally disagree with his words and I totally disagree with the racist rants of Katie Hopkins."
The debate was at times frustrating to watch and as ITV News Political Editor Robert Peston said, toward the end Mr Stewart looked "as though he has lost the will to live".
Peston added that when discussing tax cuts Mr Stewart "very explicitly" pitted himself against the other four by attacking their tax cut pledges.
Peston said: "The original idea this debate would be four against Boris is for the birds.
"Rory has decided to make it Rory against the four. It may cost him his place in contest."
Mr Raab, following his elimination from the race, tweeted: "I'm very proud of all the support I've had from colleagues in this leadership contest, and I'm immensely grateful to my terrific team. Good luck to all the candidates debating tonight!"
With Mr Johnson appearing certain of a place in the final two, the contest has become a battle for the right to a spot alongside him in the ballot of 160,000 Tory members who will choose the next party leader and prime minister.
International Development Secretary Mr Stewart's backing from 37 colleagues came after he scraped through the first round on just 19 votes.
After the results were announced, he tweeted: "Thank you all so much! Looking forward to the debate tonight @BBCPolitics #RoryWalksOn"
He added: "And thank you for all the support - we seem to have almost doubled our vote again...more to come...#walkon".
A campaign source said the extra 18 votes showed "his momentum is continuing to build", and "he can now go all the way to the final two, giving the clear choice that members deserve".
But it would appear unlikely that many supporters of the hard-Brexiteer Mr Raab will switch to Mr Stewart, so for his campaign to go further he will have to win over MPs from rival campaigns.
Mr Javid picked up 10 votes from his first-round tally to scrape through to the next ballot on Wednesday.
Environment Secretary Mr Gove picked up just four extra votes, but said he was "very pleased to have made it through and closed the gap to second".
In an apparent warning to Tories about the prospect of Mr Stewart, who voted Remain in 2016, making it through onto the final ballot paper, Mr Gove stressed: "The final two should be Brexiteers who are able to take on (Jeremy) Corbyn, unite the party and deliver Brexit."