Rory Stewart was eliminated from the Conservative leadership contest on Wednesday night, triggering a frantic scramble to win the backing of his supporters as the remaining candidates sought to secure their place alongside Boris Johnson in the next round of voting.

Mr Stewart, the international development secretary, was kicked out of the race after finishing in last place with 27 votes – strangely, ten fewer than he received in the second round of voting.

The third ballot of Tory MPs saw Mr Johnson, the frontrunner in the race to succeed Theresa May, extend his commanding lead, pick up 143 votes compared to 126 he won on Tuesday.

On Thursday, the field will be whittled down to the final two candidates, who will then be put to a ballot of party members.

Mr Stewart’s exit leaves Jeremy Hunt, Michael Gove and Sajid Javid as the remaining challengers to Mr Johnson.

Mr Hunt, the foreign secretary, and Mr Gove, the environment secretary, were closely matched on 54 and 51 votes respectively, while Mr Javid, the home secretary, was some way behind, with 38 votes.

Within minutes of the result being announced, the remaining candidates were engaged in a fierce battle to win the backing of Mr Stewart’s supporters.

Amber Rudd, the work and pensions secretary, who is backing Mr Hunt, was said to be hosting a dinner for wavering MPs, while other candidates rushed to praise Mr Stewart’s campaign.

Mr Stewart himself suggested he was unlikely to immediately endorse any of the other candidates, despite having earlier held discussions with Mr Gove about forming an alliance.

He told Sky News: “I’m actually not going to announce for anyone at the moment. I’m really pleased that for the first time in about six days I’m going to be able to get home and see my two-year-old and four-year-old, because I’ve been getting up at 6 in the morning and going to bed at 2 in the morning, so I have haven’t seen them. So I’ll go back and reflect on it.”

The international development secretary had earlier suggested that “dark arts” by Mr Johnson’s team may have cost him support.

A double round of voting will be held on Thursday to eliminate two of the remaining four candidates. Mr Johnson now has almost as many votes as his remaining three rivals combined, and is all but certain to be on the ballot paper that will be sent to 160,000 Conservative members in early July.

Mr Stewart had won plaudits for an innovative campaign that saw him thrust into the spotlight amid speculation he could prove to be the main rival to Mr Johnson. The outsider progressed in Tuesday’s ballot at the expense of Dominic Raab after picking up some significant endorsements, including that of David Lidington, the current deputy prime minister.

But his campaign stalled during a televised BBC debate on Tuesday night, with Mr Stewart later describing his own performance as “lacklustre”.

After his elimination from the contest on Wednesday, he tweeted: “I am so moved and inspired by the support I have received over the last few weeks – it has given me a new faith in politics, a new belief in our country. I didn’t get enough MPs to believe today – but they will. I remain deeply committed to you and to this country.”

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He later admitted that he did not understand how he had lost support since the previous round of voting, saying: “The reality is you never know what MPs get up to in a secret ballot. They clearly decided that they were going to back a winner and go in other directions.”

Several of Mr Stewart’s supporters posted on Twitter praising his campaign.

David Gauke, the justice secretary, said: “Disappointed that the leadership campaign of Rory Stewart has come to an end. But it has been a privilege to have supported him. He has been an inspirational candidate delivering a message of honesty and realism. He’s now a major figure in our politics with a big role to play.”

Tory grandee Sir Nicholas Soames wrote: “Terrific campaign by Rory Stewart – [the] only candidate who could reach all parts of the union. Heroic effort.”

Rory Stewart suggests combining forces with Michael Gove

As the other candidates fought to win the votes of the international development secretary’s supporters, Mr Javid said: “Thank you Rory Stewart for the positive impact you have had on this campaign. You’ve injected it with real humility, authenticity, and pragmatism. Like many I look forward to seeing the contribution you will make to our party and the country in the future.”

Amid speculation that Mr Javid has his eyes on becoming Mr Johnson's chancellor, the home secretary insisted his sights were set on Number 10 and he was “in it to win it”.

Insisting Mr Javid had been “underestimated all his life” and had “a funny habit of defying the odds” a spokesperson added: “He’s in it to win it, and he’s going to be prime minister.”

Mr Hunt’s team said they were pleased with the result, having earlier feared that their candidate could be leapfrogged by Mr Gove.