Boris Johnson and his allies have stepped up pressure on Jeremy Hunt over his refusal to commit to taking the UK out of the European Union on October 31, with or without a deal.
Mr Hunt has called the date a “fake deadline” and said he would be prepared to extend it if a deal with the EU is in reach, but Mr Johnson has made a “do or die” commitment to make sure Brexit is delivered by the end of October.
One of Mr Johnson’s most senior supporters, former leadership rival Dominic Raab, suggested he could legally ignore the will of Parliament to deliver his pledge to leave by October 31.
Former Brexit secretary Mr Raab said a Commons motion passed by MPs opposed to a no-deal Brexit would have “zero legal effect”.
Meanwhile, Mr Hunt’s campaign received a boost as Rory Stewart – another former leadership candidate – confirmed he was backing him to be the next prime minister.
Former foreign secretary Mr Johnson has said he will get the UK out of the EU on October 31 “come what may”.
MPs have previously voted against a no-deal Brexit, but Mr Raab insisted they would not be able to prevent the UK from leaving at the end of October.
“If there is a motion passed by MPs which says ‘uh-uh’, it would have zero legal effect,” he told BBC Radio 4’s Today programme.
Mr Raab said it would now be “far harder” for MPs to use “wrecking tactics” to block a no-deal Brexit.
“A prime minister that is resolute about this – Boris has been, Jeremy hasn’t – can get us out,” Mr Raab told LBC.
“More importantly, by being clear we leave at the end of October we increase our negotiating position and our strength, our leverage, to get the deal that would be acceptable to our country.”
He suggested Mr Hunt’s willingness to seek an extension could open the door to a second referendum.
“This is the question for Jeremy Hunt, if he thinks October is a fake deadline… how long will this paralysis go on for and what conditions would you accept for an extension?”
International Development Secretary Mr Stewart said he would “definitely vote against a Conservative government to stop a no-deal Brexit”, but would stop short of supporting a vote of no-confidence, which could lead to Jeremy Corbyn taking the keys to Number 10.
He told Today: “The key thing for me is a no-deal Brexit would lead to endless delay and uncertainty, would let everybody down – I will work with my colleagues to prevent that happening.”
In an open letter, Mr Johnson challenged his rival to commit to taking Britain out of the EU on October 31 “come what may”, warning that not doing so would have “devastating” consequences for the Conservative Party and the country.
However, Mr Hunt hit back, claiming that sticking rigidly to October 31 could lead to a general election which would hand power to Labour and derail Brexit altogether.
“I think that 31 October come hell or high water is a fake deadline, because it’s more likely to trip us into a general election before we’ve delivered Brexit, and that would hand the keys to Jeremy Corbyn and then we’d have no Brexit at all,” he told the BBC.
“I will leave the European Union without a deal. But I’m not going to do that if there’s a prospect of a better deal, and if I did it it would be with a heavy heart because businesses up and down the country would face a lot of destruction.”
Mr Johnson’s apparent hardening of his stance in guaranteeing Brexit “with or without a deal” came as former civil service chief Lord Kerslake said the October 31 pledge was “a complete hostage to fortune”.
In comments reported by The Independent, the former Whitehall mandarin warned that Parliament will not countenance leaving the EU without a deal.
“It is always a good maxim in politics not to enter a room unless you know that you can get out of it,” the peer told the Chamberlain lecture in London on Tuesday.
“Boris Johnson has not only entered the room but he has put on the straitjacket, padlocked the door and started the tap running.”
Mr Johnson’s Brexit plans also came under attack from International Trade Secretary Liam Fox, who slapped down the former foreign secretary over his claim that Britain could use international trade rules to continue tariff-free trade with the EU in the event of no deal.
Mr Johnson has argued that a provision under the General Agreement on Tariffs and Trade – known as Gatt 24 – could be used to avoid tariffs under World Trade Organisation rules for up to 10 years.
But Dr Fox, a Brexiteer who is backing Mr Hunt for the Tory leadership, said that would require the agreement of the EU, which Brussels has ruled out.
He said it was essential that the public debate on the issue was conducted “on the basis of fact rather than supposition”.
Mr Johnson and Mr Hunt will face questions from the public in a digital hustings on Wednesday evening.