David Cameron has admitted he is "very concerned" about the outcome of the European Union referendum, as he came under fire at a Facebook Live event hosted by Buzzfeed.
With some polls showing the Leave side ahead, the Prime Minister said it was "very competitive" with many people still genuinely undecided as to which way they would vote on June 23.
Asked if he was losing sleep over the result, he replied: "Of course."
He went on: "I am very concerned about the outcome of this referendum because I think it is so important for our country. It is bigger than a general election.
"At a general election you pick a team, if you don't like them you can kick them out in five years' time. With this, we are going to live with this decision.
"It is very competitive out there. As you go round meeting people - going to businesses, going to schools - it is a huge debate, a lot of people still making up their mind.
"In a general election when people say to you 'I haven't decided' that normally means they are being polite but they are definitely not voting for you. With this I think people really haven't decided. So each of the next 13 days is really going to count."
Cameron faced a four-letter tirade from one woman in the audience who said she would be voting for Remain even though she detested his party.
"I hate the Tories. You have fucked every fucking thing up in this country. You've screwed students, you've screwed the disabled, the vulnerable. Dodgy Dave," she said.
Cameron replied: "Obviously you and I are not going to agree about that one but we are on the same side on this one (the referendum)."
He has hinted he would still offer Boris Johnson a place in the Cabinet after the EU referendum - despite their differences on the issue.
The former London mayor came under a sustained onslaught from the Remain side in Thursday's televised debate, with Conservative cabinet minister Amber Rudd accusing him of trying to further his own ambitions to become prime minister.
However, Cameron insisted the two sides within the Conservative would come together again once the referendum was over.
"I have always said - without giving too much away - that I'm a believer in having all your stars on the pitch. Boris Johnson is a very significant figure in the Conservative Party. He was a very effective mayor of London," he said.
"Obviously on this I think he has got it wrong. I don't agree with him and I think it is a dangerous course that we'd be taking.
"As a principle, I believe as a prime minister making a team you want to have the strongest players that you can in the team."