Jeremy Hunt has promised Boris Johnson the “fight of his life” after beating Michael Gove by just two votes to become the challenger to the frontrunner in the battle to be the next Tory leader and Prime Minister.

After a day of drama at Westminster, Mr Gove was eliminated as Conservative MPs balked at the possibility of a bitter contest ahead due to the "personal psychodrama" involving the Environment Secretary and his rival Mr Johnson.

Allies of Mr Hunt had urged MPs to choose the Foreign Secretary to help keep the party together rather than risk a ferocious row between Mr Johnson and Mr Gove over the coming month of local party hustings. The Scottish one is on July 5, expected to be in Perth.

"Boris and Michael are great candidates but we have seen their personal psychodrama before," one party source declared.

Both candidates have agreed to take part in a live head-to-head debate on ITV on July 9.

Mr Hunt acknowledged he was starting well behind Mr Johnson given the parliamentary numbers. "I'm the underdog. But in politics surprises happen, as they did today.

"I do not doubt the responsibility on my shoulders; to show my party how we deliver Brexit and not an election but also a turbo-charged economy and a country that walks tall in the world."

The Foreign Secretary declared: "We are going to give Boris the fight of his life.

"He needs to be ready for that because we're going to be going out there and making strong arguments that this is the best way to deliver Brexit with someone who can go and get a better deal from the European Union."

Mr Johnson said he was "deeply honoured" to have secured the support from more than half of his Tory colleagues in the Commons.

"I look forward to getting out across the UK and to set out my plan to deliver Brexit, unite our country, and create a brighter future for all of us," he said.

There had been widespread speculation at Westminster that Mr Johnson's camp would attempt to engineer a way to prevent Mr Gove making the final pair; although the former London Mayor categorically denied being involved in any "dark arts".

Mr Gove said he was "naturally disappointed but so proud of the campaign we ran" and "it's been an honour to be able to set out a vision for the future of our great country".

Mel Stride, his campaign manager, admitted his colleague’s cocaine admission had damaged his leadership bid. “It stalled us and meant momentum was lost at that time," the Commons Leader explained.

After Sajid Javid, the Home Secretary, was eliminated in the fourth round morning vote getting just 34 votes, a few hours were left for last-minute canvassing before the fifth and final MPs’ ballot in the afternoon.

Mr Johnson again finished first, with 160 votes, an increase of three.

Mr Hunt regained second place, having lost it to Mr Gove in the fourth round of voting. He secured 77 votes, up 18, to get his name on the final ballot paper. Mr Gove received 75 votes, an increase of 14.

Amber Rudd, the Work and Pensions Secretary and a high-profile supporter of Mr Hunt said the results were "absolutely fantastic" for the Foreign Secretary and that he was "the best man to unite the country".

She tweeted: "I'm confident that our members will now see that he is the best man to unite the country, deliver a Brexit deal and turbocharge our economy. #HasToBeHunt."

John Lamont, the MP for Berwickshire, Roxburgh and Selkirk, who was an early Hunt supporter, told The Herald: “I’m very pleased Jeremy has won through to the final two candidates after a robust contest among MPs.

“The members now need to decide who is best to deliver Brexit, turbo charge our economy and protect the integrity of the UK.”

Stephen Kerr, the MP for Stirling, who backed Mr Gove, expressed disappointment but said: “Michael was brilliant. I am proud to have supported his campaign and everything he stands for.”

Ruth Davidson, the Scottish Tory leader, who backed her fellow Scot, tweeted: “Sorry, @michaelgove #kissofdeath."

Mr Javid paid tribute to Mr Gove, praising his “brilliant campaign”. He tweeted: “He is a powerful advocate for Conservative values and has been an incredible reformer in government. We will need him more than ever to face the challenges ahead."

The Home Secretary also congratulated the final two candidates for the Tory leadership, tweeting: "Congratulations @borisjohnson & @jeremyhunt. Well-deserved. Let's have a robust but positive contest, showing off the best in Conservative ideas and values."

In a forthright intervention, David Lidington, the de facto Deputy Prime Minister, warned the candidates not to focus too narrowly when courting the Tory faithful given Brexit was placing the Union at peril.

Speaking after he voted in the final round but before the result was announced, the Cabinet Office Minister noted how it was 1992 when the Conservatives last won a clear majority, of 21, while its supporters were ageing and it was losing support among black and ethnic minority voters.

“The Tory Party is facing some existential political challenges and the Union of the United Kingdom is under greater strain than I have never known it in my lifetime,” declared Mr Lidington.

“There are some key constitutional issues, some really key political challenges for the party and it’s really important that the candidates show they’re up for addressing that.”

On the Union, he stressed: “The fact that England and Wales voted to leave in the referendum and Scotland and Northern Ireland voted to remain adds to those political tensions.”

He added a no-deal Brexit “would add to the risks to the Union”.

Meanwhile, Ian Blackford for the SNP branded the Tory leadership contest “toxic” and claimed it had confirmed beyond doubt that the threat to Scotland was growing as the Conservatives lurched further to the extremes.

“Scotland must not pay the price of a petty and bitter leadership battle that could see Scotland consigned to a Brexit outcome that would be the worst of both worlds,” he insisted.

The Highland MP said crashing out of the EU without a deal would be catastrophic for Scotland’s public services, jobs and people’s living standards.

He added: “The selection of Boris Johnson and Jeremy Hunt is yet another sign that the Tory Party is intent on pushing Scotland and the UK towards the Brexit abyss and increase the prospect of an impending economic disaster.”

Labour’s Andrew Gwynne said the country now faced a choice between "the man who broke the NHS or the man who wants to sell it to Donald Trump" and called for a general election.

"A handful of unrepresentative Conservative members should not be choosing our next prime minister," added the party’s campaign chief.

The battle for the Tory crown now goes out to the 160,000 Conservative members with the first of 17 hustings taking place on Saturday in the West Midlands and the last in London on July 17.

Some 20,000 applications for accreditation have already been received.

Postal ballots will go out between July 6 and 8. The winner will be announced in the week beginning July 22.