BORIS Johnson has insisted he would oppose a second divisive EU referendum “with every fibre of my body" and warned the Conservative Party faced extinction unless it delivered Brexit and put Nigel Farage “back in his box”.

Speaking at the first Conservative leadership hustings before the so-called centre ground One Nation group of MPs in the Commons, the former Foreign Secretary ruled out a coalition with the Brexit Party and said Jeremy Corbyn's Labour was "the weakest official opposition in a generation".

On Brexit, he told Tory MPs the so-called Brady amendment to replace the Irish backstop was the only plan that had the support of the Commons.

But the bookie’s favourite to succeed Theresa May, who is set to stand down as party leader on Friday, insisted the Government must be ready for a no-deal Brexit if necessary.

Mr Johnson told the meeting of more than 80 Tory MPs that he ruled out a general election, explaining: "We are looking at a very difficult situation and we must get ready, eventually but not immediately, to beat Jeremy Corbyn and put Farage back in his box.

"We are facing an existential crisis and will not be forgiven if we do not deliver Brexit on October 31.”

He told colleagues he was best placed to lift the party, beat Mr Corbyn and excite people about Conservatism and Tory values.

"We need to realise the depth of the problems we face; unless we get on and do this thing[Brexit], we will be punished for a very long time.

"There is a very real choice between getting Brexit done and the potential extinction of this great party but I believe I can take on Farage and win back the voters being won over by him."

In a separate presentation, Sajid Javid, the Home Secretary, warned Tory MPs: "If we make the wrong choice in this leadership election we could end up with a leader who thinks the way to lead is to exploit division."

He warned: “If we don't look like change, voters will go for change in the form of Corbyn."

Mr Javid received a warm response, with banging of tables heard from outside, after telling his colleagues: "We will not beat the Brexit Party by becoming the Brexit Party."

There were also presentations from Rory Stewart, the International Development Secretary, and Andrea Leadsom, the former Commons Leader.

Backbencher Nicky Morgan, a co-founder of the group, said Mr Javid was “very responsible,” Mr Johnson was “more subdued,” Mr Stewart gave a “very direct pitch to colleagues” and Ms Leadsom was “very optimistic”.

On Brexit, Mr Javid would keep the Withdrawal Agreement but change the backstop, Mr Stewart wanted a Brexit Council to unlock the parliamentary process but wanted to avoid a no-deal outcome at all costs, Mr Johnson said the current agreement did not work, he did not want a no-deal Brexit but argued the country had to prepare for one and believed a second poll was anti-democratic while Ms Leadsom wanted a managed exit with a range of mini-deals with Brussels. They all ruled out doing a deal with the Brexit Party.

There are six more group hustings.

Earlier in the day, two contenders, James Cleverley and Kit Malthouse, the respective Brexit and Housing ministers, pulled out of the contest, meaning the number of candidates is reduced from 13 to 11.

In a separate development, the party’s backbencher 1922 committee set out the rules for the contest:

*a call for candidates will be made on Friday with nominations opening at 10am on Monday and closing at 5pm that day;

*ballots of MPs to whittle down the candidates will then be held over the course of the following two weeks with the first on June 13 with subsequent rounds on June 18, 19 and 20 if required;

*after the first ballot, any candidate receiving 16 votes or fewer will be eliminated;

*after the second ballot, any candidate receiving 32 votes or fewer will be eliminated;

*if the ballot thresholds are met by all candidates, then the candidate with the lowest number of votes will be eliminated;

*balloting will continue until two candidates remain;

*the first membership hustings are planned for June 22 and

*the process will be completed in the week beginning Monday July 22.