Tory leadership front-runner Boris Johnson's bid to become prime minister received a fresh boost as former Brexit secretary Dominic Raab backed his campaign.
The endorsement of Mr Johnson by the hardline Brexiteer came as fellow leadership contender Rory Stewart said he was in talks with Michael Gove on "combining forces" in the contest.
Such a move would be seen at Westminster as a "Stop Boris" bid in the battle for the Tory crown.
Mr Raab, who was eliminated from the contest in the second round after receiving support from only 30 MPs, said Mr Johnson was the sole contender who would ensure Brexit happened by October 31.
He told the London Evening Standard: "The only candidate who will now do this is Boris Johnson – and so I'll be supporting him to become our next prime minister.
"Boris will make sure we leave the EU on time and move on to uniting the country behind a positive programme where everyone can benefit from the UK's success."
International Development Secretary Mr Stewart said discussions with Mr Gove centred on who would be best placed to challenge the former foreign secretary in the run-off between the last two candidates left standing.
Mr Stewart told the BBC: "We are talking about combining forces because it's clear that Boris is going into the last round.
"And the question is 'Who is best placed to sit on stage with Boris Johnson, and who is best placed to ask the testing questions that need to be asked?'"
However, the two candidates' camps clashed over who would remain in the race if Mr Stewart and the Environment Secretary joined forces.
A Stewart campaign spokeswoman said: "Clearly at some point people will need to combine teams.
"But any team that gets combined, Rory wants to lead it. Rory's in this to win."
And a source in the Gove camp insisted the Environment Secretary had no intention of quitting.
The source said: "We are in it to win it and we would obviously welcome the support of any candidate that wanted to drop out and support us."
Mr Stewart nearly doubled his backing to 37 votes in Tuesday's second ballot of Tory MPs, leaving him just four votes behind Mr Gove.
The move came as fellow leadership hopeful Jeremy Hunt took a swipe at Mr Johnson's Brexit stance, insisting his rival has an unclear policy and suggesting he is not trusted in Brussels.
The Foreign Secretary said he was "not entirely sure" what the front-runner believes when it comes to when Britain will leave the EU.
In a televised debate on Tuesday evening, Mr Johnson said the October 31 deadline for Brexit must be met, warning that otherwise there would be a "catastrophic loss of confidence in politics".
But Mr Hunt accused the former foreign secretary of lacking clarity on whether he guaranteed delivering Brexit by the end of October.
He told BBC Radio 4's Today programme: "Well, I am not entirely sure what he believes on this, having listened to him last night.
"You have to think these things through because prime ministers have to make these judgments."
Mr Hunt, who came second in Tuesday's ballot, also said he was best placed to cut a deal with Brussels on Brexit, saying: "We need a negotiator."
He said a negotiator has three qualities: "The first is it has to be someone the other side trust, because you don't do a deal with somebody you don't trust.
"Secondly, it has got to be someone who doesn't blink. And thirdly, it has got to be somebody who is prepared to walk away.
"Now, the danger is that if we choose the wrong person now, we will have no trust, no negotiation, no deal, and possibly, if we have an election, no Brexit."
Another candidate will face the axe on Wednesday afternoon – with Mr Johnson, Mr Hunt, Mr Gove, Mr Stewart and Home Secretary Sajid Javid battling it out for the top job.
The first debate on Tuesday night is unlikely to have swayed many MPs' minds, ending with no clear winner after a fractious debate taking in Brexit, Islamophobia and climate change.
However, Mr Gove claimed on BBC Newsnight that he "won the debate", "because I had the most detailed answers and I have a clear plan to how we can deliver Brexit and make sure we get all the benefits of life outside the European Union".
As the candidate who currently has the fewest backers, there are rumours that Mr Javid could drop out, but supporter Stephen Crabb told the BBC his favoured candidate had performed well in the debates and was not about to quit.