Gordon Brown insisted today he was fighting for "five more years" as Prime Minister.
He said that serving the country was all he wanted to do, but he maintained he would be able to cope without power if Labour was to be swept from office on May 6.
The Premier suggested he would spend much of his time writing if he found himself outside politics.
Business Secretary Lord Mandelson recently opened the prospect that Mr Brown might not serve a full term, if re-elected.
He said in an interview earlier this month that voters had the chance to "go five more years, or four, or three, or however many it is, with the person they know and can depend on".
Asked about Lord Mandelson's remarks today, Mr Brown told BBC Radio 4's Today programme: "I will be standing for the next five years."
Put to him that Tony Blair had promised to serve a full third term at the 2005 general election - only to retire two years later - Mr Brown re-emphasised "five more years".
He rejected the suggestion that politics had been his entire life, pointing out that he had first been "an academic".
Asked whether he could cope without politics, in the event of a Labour defeat, he said: "Of course, I've written half a dozen books, I've done speeches about things other than politics. I'm fascinated by other issues. But I'm here to win..."
He said he would not now return to being an academic, saying: "I like writing."
But he added: "I'm here with one purpose - to serve my country, it's the only thing I want to do."
Mr Brown defended his record as chancellor in the face of suggestions that he had helped create the conditions which led to the financial crash of 2008 with his claims to have abolished "boom and bust".
"I have just got to be pretty straight with you. If you can keep inflation low and you can keep interest rates low and if you have an economy that is growing and if you have got 2.5 million more people in work, then people have a right to believe that the measures you have taken are going to keep inflation remaining low and interest rates remaining low," he said.
"What blew us off course was a global financial crisis. It wasn't the level of debt in Britain, particularly not the level of public debt in Britain."Reuse content