Boris Johnson has challenged Jeremy Hunt - his rival for the Tory leadership - to commit to taking Britain out of the EU by the end of October.
After days avoiding journalists' questions, the former foreign secretary sought to get his campaign back on track, declaring he would deliver Brexit by the Halloween deadline "come what may" and "do or die", should he become prime minister.
In recent days the former mayor of London's campaigned has been blighted first by the news that police were called to a with his girlfriend, Carrie Symonds, and then allegations that a photo released of the pair together was staged.
Police who attended the scene on Friday night said they found everyone "safe and well" and that no further action was taken.
In a bid to focus his leadership campaign on other issues, Mr Johnson abandoned his "submarine strategy" after being called a "coward" by rival Jeremy Hunt, and sought to move the focus on to Brexit, the issue dominating the race, on Tuesday.
The Tory leadership frontrunner had been avoiding the media spotlight, deigning to appear at only one of four hustings so far, and refusing journalists' requests for interviews and information, but beginning late on Monday night he began a string of television and radio appearances
But the Vote Leave leader has suddenly resurfaced with a surge of TV and radio appearances starting late on Monday night.
In focusing on the deadline of October 31, the date by which Mr Johnson has stated the UK will leave the EU with or without a deal, he sought to appeal to Tory voters with his black and white standpoint, compared to Mr Hunt who has said he would like to exit the bloc by this point, but has not stated it as a hard and fast rule.
Mr Hunt, meanwhile, hit back at his rival, dismissing October 31 as a "fake deadline" which would more likely result in a general election which could hand the keys of No 10 to Jeremy Corbyn.
The Foreign Secretary suggested Mr Johnson would be unable to win the trust of other EU leaders to successfully negotiate a new Brexit deal with Brussels.
ITV News also stated that Mr Johnson's "do or die" Brexit by Halloween could lead to a general election, since if the former foreign secretary becomes prime minister and is unable to deliver Brexit by October 31 as he has pledged, it could result in a vote of no confidence in his government, resulting in an election.
In a letter to his rival, Mr Johnson said the "central question" in the leadership contest was the issue of whether the next prime minister would commit to leaving the EU by October 31.
"If we fail to deliver once again, the consequences for our party and our country will be devastating," he said.
"We must not kick the can down the road again. The British people have had enough of being left in limbo."
Mr Hunt responded to the letter criticising Mr Johnson for not taking part in a televised debate on Sky News which had been scheduled for Tuesday evening.
Instead, during the time when he would have been on TV, the Foreign Secretary responded to questions on Twitter which ranged from Brexit deadlines, to the NHS, broadband and climate change.
In another swipe at his rival earlier on Tuesday, Mr Hunt suggested the next prime minister must be "trustworthy" in order to deliver a Brexit deal.
In the interview with the BBC, the 52-year-old also warned that insisting upon the October 31 departure date was a mistake.
"I think that October 31 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 said.
While he said that getting a new deal by the end of October was "doable", it required a prime minister who the other EU leaders trusted and were prepared to talk to.
"It's about the personality of our PM. If you choose someone where there's no trust, there's going to be no negotiation, no deal," he said.
Mr Hunt also said on Tuesday that he believed it would become clear "well before" October 31 if it was possible to get a new deal with the EU.
"If there isn't and if no deal is still on the table I've been very clear. I will leave the European Union without a deal," he said.
"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 disruption."
Breaking the silence that was beginning to become the talking point of his campaign, Mr Johnson used a series of broadcast interviews on Tuesday to set out his plans for Brexit, insisting that the shock of the European election results would force both the Tories and Labour to acknowledge that the current impasse could not continue.
Mr Johnson told TalkRadio the UK would be leaving the EU on October 31 "do or die, come what may".
He said some "positive energy" would help deliver Brexit, hitting out at the "pathetic" efforts of Theresa May's administration - a government in which he served as foreign secretary for two years until July 2018.
"I've never seen such morosity and gloom from a government," he said.
"For three years we've been sitting around wrapped in defeatism telling the British public that they can't do this or that. It is pathetic, it's absolutely pathetic."
Yet despite his attempts to focus the leadership race on Brexit, Mr Johnson was repeatedly met with questions about his row with Ms Symonds and the ensuing photograph - two issues he has refused to discuss.
In one interview alone, Mr Johnson refused 26 times to answer questions about whether the photographs were staged.
On LBC Radio, he was repeatedly challenged about whether his campaign was behind the release of a picture of him with Ms Symonds in an attempt to show their relationship was going strong.
Asked where the photograph had come from, Mr Johnson said: "The longer we spend on things extraneous to what I want to do... the bigger the waste of time."
In testy exchanges, he said there are "all sorts of pictures of me out on the internet which pop up from time to time".
When host Nick Ferrari suggested his hairstyle indicated it was an old picture, he said: "This conversation is now descending into farce."
Turning to Brexit, Mr Johnson said "politics has totally changed" since March 29 and "we are staring down the barrel of defeat" which would focus minds in Parliament.
"People are looking at this thing and thinking 'Parliament is just not going to do this'. But, actually, I think they are."
"I do not comment on that kind of thing and it would be breaking a long standing rule, which has served me well for decades," the 55-year-old insisted.
Despite Mr Johnson's unwillingness to speak about the picture, some appeared happy to talk on his behalf, with ITV News Political Editor Robert Peston told that the decision to release the photo had been made in part by Ms Symonds, a former director of communications for the Conservative Party.
Meanwhile ITV News At Ten Presenter Tom Bradby was told that the photograph had been taken on Sunday.
On Tuesday it was also announced that the winner of the Tory leadership race will be announced on July 23 under the timetable set out by the Conservative Party.
After the field of those wishing to become the next Tory Party leader was whittled down to two from 13 by Conservative MPs, during the next few weeks all will get the chance to vote on who their next party leader will be, thereby selecting the next prime minister.
Theresa May is expected to hand over the reins of power the following day after taking Prime Minister's Questions for a final time.