MercoPress. South Atlantic News Agency

PM Brown admits he is the underdog in the forthcoming general election

UK Gordon Brown has admitted he is the underdog in the forthcoming general election battle - but insisted he is ready to “fight” for Britain.

The Prime Minister said voters faced a "big choice" between the Tories promise of "austerity" and Labour's plans to encourage "aspiration".

He also rejected claims that he was engaging in class warfare against David Cameron, and dismissed suggestions of splits in Labour's top team. The comments, in an interview for BBC1's Andrew Marr Show, effectively fired the starting gun on an election campaign that could last five months.

Asked whether he regarded himself as the underdog in the contest, Mr Brown replied: "I think when you are behind in the polls you have got to regard yourself as the fighter. Everything I have ever won in my life I have had to fight for...

"People will see they have a choice to make and the choice is between someone who is ready to fight for every aspect of Britain's future, and will not stop fighting."

Mr Brown seemed to let slip that the crunch ballot would not take place in the first few months of this year, saying he "believed" there would be a Budget in the spring.

And he turned his fire on the Tories, insisting Mr Cameron had hoped to win without his own policies being scrutinised. "I think the Conservatives wanted an election that was essentially a referendum," he said.

The PM sought to make light of his barb in the Commons that Mr Cameron had dreamed up his inheritance tax policy "on the playing fields of Eton".

"It was a Commons joke. Quite an effective one, I hope," Mr Brown said. "I don't attack him for being a toff. I attack him for having the wrong views".