Boris Johnson renewed his vow to take Britain out of the EU on 31 October, but admitted that withdrawal without an agreement will hurt the UK in the short term.

Breaking cover to launch his campaign for the Conservative leadership in Westminster, Mr Johnson said he had the “vigour” and “guts” to persuade the EU27 to renegotiate the terms of Brexit and talked at length about his time as London mayor.

But he dodged questions about whether he had taken illegal drugs and cut the event short after just six questions from the media, to the anger of many journalists who still had their hands raised.

As MPs prepared to vote on a cross-party motion to allow the Commons to block no deal, the favourite to succeed Theresa May as prime minister issued a warning that parliament will face “mortal retribution” from the electorate if it tries to stop Brexit.

He received loud applause from an audience including Brexit hardliners like Jacob Rees-Mogg and Mark Francois as he said: “After three years and two missed deadlines, we must leave the EU on 31 October and we must do better than the current withdrawal agreement that has been rejected three times by parliament.”

Put It To The People march: Best of The Independent’s pictures Show all 24 1 /24 Put It To The People march: Best of The Independent’s pictures Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent

Mr Johnson said that no deal was a “last resort” and he was focusing on getting a “better deal” from Brussels within the next five months.

But he said that the UK must show it is preparing seriously for no deal in order to persuade EU negotiators to give ground.

“It’s only if we have the guts and courage to get ready for it that we will carry any conviction in Brussels and get the deal we need,” he said.

In an apparent swipe at rivals for the Tory leadership, such as Michael Gove and Jeremy Hunt, who have suggested that Brexit negotiations may have to be extended beyond 31 October in order to ensure a deal, Mr Johnson suggested that any further delay could be fatal for the Conservatives.

“Delay means defeat,” he said. “Delay means Corbyn. Kick the can again and we kick the bucket.”

Mr Johnson said he would offer “a new vigour, a new confidence, a new optimism about what we can do, and total conviction about the way forward”, and said he was hopeful that there would be a “symmetrical enthusiasm across the Channel” to devise a new deal. “I think we will get results,” he said.

But he admitted that a no-deal Brexit would hurt voters, in the short term at least. “I’m not going to pretend to you now that everything will be plain sailing,” he said.

“There will be difficulties and there may be bumps in the road, but my team will hit the ground running and we will work flat out between now and 31 October.

“And I think we will get the result that the country needs: a sensible, orderly Brexit that allows this country to flourish as a great independent nation but also builds a new partnership with our friends across the Channel.”

Mr Johnson warned Tories that a failure to deliver Brexit by 31 October would “alienate not only our natural supporters and drive them into the arms of insurgent parties, but anybody who thinks politicians should deliver on their promises”.

The former foreign secretary’s 12-minute speech and 20-minute question-and-answer session was repeatedly interrupted by shouts of “stop Brexit” from campaigners on the street outside.

And Mr Johnson’s supporters booed a television reporter when she asked about his past comments comparing Muslim women in burqas to letter boxes.

He won loud applause when he replied: “One of the reasons that the public feels alienated now from us all as a breed, is because too often they feel that we are muffling and veiling our language, not speaking as we find – covering everything up in bureaucratic platitudes, when what they want to hear is what we genuinely think.

“If sometimes in the cause of trying to get across what I genuinely think, I use phrases and language that have caused offence, of course I am sorry for the offence I have caused, but I will continue to speak as directly as I can.”

Mr Johnson insisted that he would stand up for the world of commerce and industry, despite having reportedly privately said “f*** business”.

“I don’t think there is anybody in the modern Conservative Party who can honestly be said to have done more to stick up for business, even in the toughest of times. I will stick up for them.”