Prime Minister Gordon Brown has brushed off rumours that he might quit ahead of the general election, declaring: "Of course I'm going on."
Unconfirmed reports have suggested Mr Brown might use ill-health as an excuse for standing down before the poll, and former Cabinet minister Charles Clarke today said he should go "for his own dignity".
But in an interview for the New Statesman magazine, Mr Brown said he was "pretty determined and resolute" to carry on.
In the interview, conducted before the PM's current trip to the US and published tomorrow, Mr Brown said the election, which must take place within nine months, would offer voters a "big choice" over which party is most likely to "lead growth and prosperity ... (and) build a fairer and stronger society".
Rows over less fundamental issues would fade away as polling day approaches, he suggested.
"This will be a big choice election," said Mr Brown. "You've got to ask yourself: which is the party that is going to lead the growth and prosperity that we need to go into the future? Which is the party most likely to build a fairer and stronger society?
"It's not going to be the small issues that other people want to be the focus of the election, and I think the country will know that by the time the election comes."
Asked about his leadership, Mr Brown said: "Of course I'm going on. I mean, for goodness sake, I wouldn't be having this interview with you if I wasn't determined to get my message across to the British people.
"I hope that people will see by my actions the determination I have to work not just on behalf of the Labour Party but on the behalf of the British people."
Challenged to give a "cast-iron guarantee" that he will lead Labour into the election, he responded: "The issue at the moment is that the Labour Party has to take this country through a very difficult time and I think we'll be judged by results.
"I've got a job to do ... So I'm pretty determined and resolute."
He dismissed recent reports that his predecessor as prime minister saw him as "a quitter, not a fighter" who might duck the election, telling the New Statesman: "I don't think Tony Blair has ever said that."
Mr Brown admitted it was difficult to get his message across in the face of "a very hostile opposition and media".
"I've got my ideas and I've got my views about the future and it's my duty and my responsibility to get these across," he said. "I accept that you're dealing on occasion with a very hostile opposition and media but it's my duty to get my views across.
"It's difficult sometimes to explain how resolute I am about the challenges ahead ... Taking a country through a very difficult recession requires some of the most difficult judgments and decisions, and you can't always explain that while ... the press is focused on some issues, you are actually trying to deal with big issues of concern."
Mr Brown dismissed David Cameron's claim that the Conservatives are now the "progressive" party, saying: "I find it difficult to believe those people that want to call themselves progressive also want to, for example, cut inheritance tax for millionaires at the expense of public services. You can't be progressive and want in a recession to cut help for the unemployed: it is just not possible."