Gordon Brown will set out his vision of another decade of Labour government today and leave the door wide open to an autumn general election.

With election fever gripping the Labour Party at its Bournemouth conference, Mr Brown and his closest supporters have been deliberately keeping the prospect of an early poll hanging over this week’s gathering and next week’s Conservative conference. Labour MPs in marginal seats are said to be telling the whips that Mr Brown should capitalise on his strong standing and go for broke.

The speculation was fuelled further last night as an Ipsos-MORI poll for The Sun gave Labour an eight-point lead with a rating of 42 per cent, equalling the highest in any poll since Mr Brown became leader. The Conservatives were on 34 per cent and Liberal Democrats on 14 per cent.

David Cameron has put the Tories on alert for an election even though some strategists think that Mr Brown’s natural caution will stand in the way.

The former Cabinet minister Michael Portillo admitted that the prospect of an early election was a cause of great concern to his party. On the ITV1 Sunday Edition programme, Mr Portillo said: “The atmosphere that there might be an election very, very soon is dominating thinking and, I think, frightening the Tories.”

Early November, rather than late October, was emerging as a more likely election date if Mr Brown chose to gamble on an autumn poll. The Prime Minister is believed to be keener on waiting for Parliament’s return on October 8 before making his decision. Ministers say he believes that announcing the poll during the Conservative conference might be seen by the public as opportunistic.

If he decides to wait, he would lose the option of going to the country on October 25; an election that day would have to be called by next Tuesday.

Mr Brown will give no hint of the timing in his first speech to the conference as Prime Minister. He wants to use his speech and those of other ministers to show off Labour’s programme as the alternative to the Tories. A close aide claimed that the election campaign was under way whether or nor Mr Brown called a poll for the autumn.

The Prime Minister is said by friends not to have made up his mind on the election, but he risks confusion by simultaneously trying to keep the prospect alive while claiming that he is focusing on doing his job. Yesterday there was a flurry of speculation after Ed Balls, the Schools Secretary and Mr Brown’s closest adviser, said that Labour would need months to lay out its new policies under Mr Brown. However, party strategists swiftly rejected the idea that Mr Balls was “pouring cold water” on an autumn election, and made plain that he had not intended to do so.

In addition, they described a letter from Mr Brown to the Labour executive setting out his priorities as a “draft manifesto”, fuelling election talk yet further. In the letter, the Prime Minister repeatedly referred to the “decade ahead” as he set out the challenges facing his party.

These included responding to rising public aspirations with a new standard of public services, globalisation, security and terrorism, social change and environmental issues.

Asked on The Andrew Marr Show on BBC One whether his aides were advising him to go to the country within weeks, Mr Brown said: “No. I’m actually getting on with the job. My focus is on the work ahead, the return of Parliament, Iraq, the health service.”

Vince Cable, the Lib Dem Treasury spokesman, said Mr Brown might be tempted to call a snap election to get it out of the way because the economy could be about to go badly wrong.

The Tories hit out at the Prime Minister, saying he had evaded questions in his television interview about what he knew and when over the Northern Rock crisis. George Osborne, the Shadow Chancellor, said: “Gordon Brown cannot give straight answers to the simplest of questions. He was repeatedly asked when he first knew about the problems at Northern Rock, and he refused to answer. What is he trying to hide? Why can’t Gordon Brown be straight with people?”

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