Boris Johnson at his campaign launch. He added that "it is astonishing to think that anyone could suggest dispensing with that vital tool in the negotiation". Because the Conservatives are the UK's governing party, the victor of the race automatically becomes prime minister - and steps into a paralyzing Brexit impasse which Theresa May has tried and failed to break.
Former foreign minister Johnson, front-runner in the race to succeed Theresa May, officially launched his campaign earlier on Wednesday with a commitment to lead Britain out of the European Union on October 31.
At a launch event in London packed with senior members of the ruling Conservative party, Johnson insisted that Brexit must happen on October 31, the latest deadline agreed with Brussels.
Mr Johnson ran for the leadership in 2016 but pulled out before the first round of voting after Mr Gove, who was at the time his campaign manager, withdrew his support, questioning his aptitude and appetite for the job.
In a swipe at his rivals, he argued: "We can't risk going with [the] short-term comfort zone choice". "I've got a credible and honest plan for delivering Brexit by the end of October".
The Labour Party has tabled a cross-party motion in an effort to block a no-deal Brexit.
Mr Johnson is regarded as the frontrunner in the contest, with many more endorsements from Tory MPs than any other candidate.
He will say his two election victories as London mayor mark him out as the person most able to beat Jeremy Corbyn.
Ten Conservative lawmakers are running to succeed Theresa May as party leader and prime minister.
Mr Johnson, who is the clear front-runner in the leadership race, had to fend off a series of reporters' questions about his past character and record in office.
Earlier, Mr Johnson launched his bid to succeed Theresa May with a warning that Britain must leave the European Union by the latest deadline of October 31, with or without a deal.
Labour leader Jeremy Corbyn has said a no-deal Brexit would be "disastrous", telling MPs: "I think some of [the PM's] colleagues need reminding of that".
"Occasionally some plaster comes off the ceiling as a result of a phrase I may have used, or indeed as a result of how that phrase has been wrenched out of context and interpreted by those who wish for reasons of their own to caricature my views", he said on Wednesday.
"We will simply not get a result if we give the impression that we want to go on kicking the can down the road and yet more delay", Johnson said.