Boris Johnson has refused to say whether he would quit should the Tories fail to win the general election.
The PM's decision to push for the snap vote could see Jeremy Corbyn make his way into Number 10, which would see Mr Johnson one of the shortest-serving PMs in British history.
Despite polls putting the Conservatives ahead, the prime minister has said he believes there is a real prospect of a Labour and SNP coalition coming into power.
However, pressed on his concerns at the prospect of not winning the vote, he would not be drawn on his political future.
Asked three times if he would stand down if he fails to secure a majority, the PM admitted he was nervous and "fighting for every vote" ahead of the poll.
Pressed on if he would resign if it did not go his way, by Sophy Ridge on Sky, he replied: "The choice on Thursday is unbelievably stark, it's between going forward with a one nation Conservative government that can get Brexit done...
"Or spending the whole of next year in complete paralysis with two referendums, one on Scotland, one on the EU when Jeremy Corbyn cannot even tell us what his position is on Brexit and who is going to campaign for the deal that he proposes to do."
Pressed again, Mr Johnson said: "If you don't mind, Sophy, what I'm going to do is concentrate on the five days before us because that is what I think the people of this country would expect.
"We have got a very short time to get our message across, it's a message of hope and optimism about this country."
It came as he laid out plans for an Australia-style immigration system should the Tories form the next Government, as leaders rallied ahead of Friday's vote.
