Cabinet minister Amber Rudd, an ally of Mr Hunt, raised the threat of fresh Tory divisions by refusing to say whether she would be prepared to serve in a government headed by the former foreign secretary. Last night Mr Johnson’s leadership rivals turned on him in a television debate that he refused to take part in. “Where is Boris?” Jeremy Hunt asked. “If Boris’s team won’t let him out to debate with five fairly friendly colleagues, how’s he going to fare with 27 countries?”
Mr Johnson previously described the debate as “cacophonous” and has instead agreed to appear in a BBC clash tomorrow after the next knockout round has slimmed down the field of candidates.
He was given an extra boost yesterday when Esther McVey, who was eliminated in the first ballot for the leadership contest, confirmed she was now backing him.
Mr Johnson was also expecting to gain the support of fellow Cabinet minister Matt Hancock.
The Health Secretary, who withdrew from the leadership race on Friday, is understood to have decided to back Mr Johnson after talks with all the remaining candidates over the weekend.
His decision will be seen as hugely significant because of his close links with former chancellor George Osborne, who he worked for as a Treasury adviser before becoming an MP.
Mr Hancock is expected to urge his supporters to vote for Mr Johnson in the second round, although aides acknowledge some will back other candidates.
While the frontrunner kept a low profile yesterday, other leadership candidates were out in force to rubbish his promise of withdrawing the UK from the EU by October 31, with or without a deal.
Mr Hunt, who came second in last week’s leadership vote, pitched himself as “the alternative to Boris” who could negotiate a new Brexit deal.
Speaking on BBC1’s The Andrew Marr Show, the Foreign Secretary said: “I’m offering a different approach which allows us to negotiate a deal that we can get through parliament.
“The difference between me and Boris is I’m saying I would try for a deal. I believe it is possible to offer better choices – that’s what negotiators do and that’s why I’m standing.”
Mr Hunt insisted his contacts with EU leaders including German Chancellor Angela Merkel and French President Emmanuel Macron gave him faith that a new deal was possible.
“They want to solve this problem,” he said.
“If they were approached by a British prime minister, someone they were willing to deal with, they would be willing to renegotiate the package.”
Rory Stewart, another candidate, said Mr Johnson could not be trusted to be prime minister.
In a blistering attack on the same BBC programme, the International Development Secretary said: “I don’t even know what he believes.
“He won’t talk to me, he won’t talk to you, he won’t talk to the public...the real problem in politics is a problem of trust.”
Mr Stewart also reiterated his threat not to serve in a Cabinet under Mr Johnson. He said yesterday: “There are two completely different visions facing our country – Boris’s vision and my vision. I would not serve under a Boris Cabinet.”
Last night, Mr Johnson was taunted by Tory critics after failing to appear for the first live TV debate of the Tory leadership contest.
An empty podium was left in the middle of the Channel Four clash after the frontrunner declined to take part. As Britain’s Next PM was broadcast, senior Tory MP Sir Nicholas Soames said on Twitter: “Actually truly dismal that Boris Johnson can’t be fagged to turn up and discuss his ‘leadership’ plans on Channel Four hustings.”
During the 90-minute show, Mr Hunt and rivals Michael Gove, Sajid Javid, Rory Stewart and Dominic Raab clashed repeatedly over Brexit and other policy plans.
In one heated exchange, Rory Stewart accused all his rivals of indulging in “machismo” for claiming they could extract a better Brexit deal from the EU by threatening to walk out of negotiations.
One report yesterday claimed Mr Stewart was being backed by Theresa May in the hope of frustrating her old foe Mr Johnson.
According to the report, the PM voted for Mr Stewart in the first round ballot. But an ally of Mrs May said: “She has not told a soul how she voted. This report should be treated with extreme scepticism.”
Mrs Rudd, the Work and Pensions Secretary, yesterday intervened in the leadership debate to claim MPs were in danger of being “misled” by Mr Johnson.
She also revived a jibe from a television debate during the 2016 EU referendum campaign that she would not want Mr Johnson to drive her home after a night out.
Mrs Rudd told Sky News Sophy Ridge On Sunday show: “I am still thinking very carefully about any lifts home from Boris.”
Senior Tories fear the “blue on blue” attacks between leadership rivals are damaging the party.
Cabinet minister Liam Fox, who is backing Mr Hunt, last night said that everyone in the contest should “play nice”.
He added: “The reputation of the Conservative Party is on show. We will all need to work together afterwards.”