Jeremy Hunt has warned that the Tories will be "annihilated" in an early general election, in an attack on Boris Johnson's Brexit strategy.

The foreign secretary issued the thinly-veiled criticism of his rival's "empty rhetoric" over a no-deal Brexit, which he warned would trigger a general election and let Jeremy Corbyn into Downing Street.

Mr Hunt has swung to the forefront of the contest with the surprise backing of cabinet Brexiteer Penny Mordaunt, who boosted his Eurosceptic credentials by saying she "trusts" him to deliver on Brexit.

Her endorsement comes after Amber Rudd, the pro-EU work and pensions secretary, threw her weight behind Mr Hunt's campaign - bolstering his chances of being Mr Johnson's primary challenger.

It comes on a busy day in Westminster as Matt Hancock, Esther McVey, Dominic Raab and Michael Gove were all set to officially launch their bids.

Who could succeed Theresa May as Conservative leader? Show all 9 1 /9 Who could succeed Theresa May as Conservative leader? Who could succeed Theresa May as Conservative leader? Boris Johnson Former foreign secretary Boris Johnson has long been hopeful, he previously stood in the leadership contest that followed the Brexit vote and has at many times since been thought to be maneuvering himself towards the goal. He remains a darling of the party's right wing, particularly those in the ERG, and is the most popular choice among Tory voters but his leadership bid would be fiercely opposed by many MPs PA Who could succeed Theresa May as Conservative leader? Michael Gove Environment secretary Michael Gove is another member who has long wanted to be leader. He has lately been known for rousing his party in the commons, his recent speeches on the Brexit deal and Labour's no confidence motion have overshadowed the Prime Minister's. He has been loyal to the Prime Minister, partly to shed his reputation as a backstabber who abandoned Boris Johnson to stand against him in the 2016 leadership election Getty Who could succeed Theresa May as Conservative leader? Dominic Raab Former Brexit secretary Dominic Raab has emerged as a favourite to be the Brexiteer candidate in a contest to succeed to Ms May. He displayed a grip on detail in his role as Brexit secretary. When asked recently if he would like to become prime minister he replied "never say never" Getty Who could succeed Theresa May as Conservative leader? Rory Stewart International development secretary Rory Stewart is pitching himself as the sensible candidate, promising to rule out both a second referendum and a no-deal Brexit. He was only recently promoted to the cabinet, previously serving as prisons minister, where he caught headlines with a pledge to resign if he could not reduce levels of violence within a year PA Who could succeed Theresa May as Conservative leader? Esther McVey The former work and pensions secretary announced that she will be standing for the leadership when May leaves. McVey is the first to explicitly state that she intends to stand. She resigned from the cabinet in protest over May's Brexit deal AFP/Getty Who could succeed Theresa May as Conservative leader? Sajid Javid Home secretary Sajid Javid is said to have a plan in place for a leadership race. He made headlines over Christmas when he declared that people smuggling over the English channel was a "major incident" and more recently when he revoked the citizenship of ISIS bride Shamima Begum. Son of a bus driver, he wants the Conservatives to be seen as the party of social mobility PA Who could succeed Theresa May as Conservative leader? Jeremy Hunt Foreign secretary Jeremy Hunt was recently thought to be the favourite in the event of a leadership race as he could sell himself as the man to unite the party. Critics worry that his long stint as health secretary could return to haunt him at a general election. He has reportedly been holding meetings with Tory MPs over breakfast to promote his leadership PA Who could succeed Theresa May as Conservative leader? Andrea Leadsom Following the Prime Minister's second defeat over her Brexit deal, Leader of the house Andrea Leadsom hosted a dinner party at which "leadership was the only topic of conversation", The Times heard. Leadsom ran against Theresa May in the 2016 leadership election before dropping out, allowing May to become Prime Minister AFP/Getty Who could succeed Theresa May as Conservative leader? Priti Patel Former international development secretary Priti Patel is thought to be positioning herself as a contender. One MP told The Independent "she knows she's from the right of the party, the part which is going to choose the next leader, so she's reminding everyone she's there." Patel left the government late in 2017 after it emerged that she had held undisclosed meetings with Israeli officials PA

Speaking at his campaign launch, Mr Hunt took a swipe at Mr Johnson, who has advocated leaving the EU on 31 October with or without a Brexit deal.

Mr Hunt said: "Without a deal, any prime minister who promised to leave by a certain date would have to call a general election to change the parliamentary arithmetic.

"An election we would lose badly. Because the lessons of the European and Peterborough elections are clear. If we fight an election before delivering Brexit, we will be annihilated.

"Squeezed by the Brexit Party on the right and the Lib Dems on the left, we simply allow Labour through the middle."

Mr Hunt said the country was facing a "constitutional crisis" and urged Tories to "get real".

He said: "This extremely serious moment calls for an experienced, serious leader.

"We need the art of tough negotiation, not the art of empty rhetoric.

"And faced with bad choices, we need a prime minister who can negotiate some better choices."

Mr Hunt also told the audience that no government he leads will change the law on abortion, despite admitting he personally believes the legal time limit should be halved to 12 weeks.

He also said he had never committed a crime, as his rival Michael Gove's campaign stalled amid controversy over his cocaine use when he was working as a journalist.

Elsewhere, Mr Raab tried to paint himself as "the conviction Brexiteer with a plan" and said his rivals were only offering "bluff and bluster".

The former Brexit secretary, who has previously suggested suspending parliament to force through a no-deal, vowed he would break from the EU by 31 October, even without a deal.

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Mr Hancock, the health secretary, ruled out proroguing parliament in order to ensure the UK leaves the EU on October 31 and said no-deal would not get through the Commons.

He has previously set out a Brexit delivery plan to leave by October 31, including establishing an Irish border council, made up of UK and Irish officials, to prevent the return of a hard border and time-limiting the backstop.

Ms McVey, a hardline Brexiteer, said the Brexit negotiations to date had been a "national embarrassment".

Criticising Theresa May's efforts she said: "As far as I'm concerned there could have been literally any outcome with her at the helm, apart from the one we wanted.

"Because she was not going to leave the EU without a deal. At the very least something that could be described as EU lite. But the way I was looking at it, it was EU watertight.

"We could have ended up being in there (the EU) and having no say."