Gordon Brown's Labour conference speech - live

Hooray for Harriet HarmanHarriet Harman. When she was invited on the BBC this morning to agree that Gordon BrownGordon Brown had to give "the speech of his life", she was having none of it. There may have been a flaw in her analysis – "it is not a make-or-break speech for Gordon, because Gordon has already shown everyone in this party what a great leader he is" – but at least she did her bit to bury one of the worst cliches in British politics.

It's rare for anyone to deliver a genuine, make-or-break game-changer. (Neil Kinnock probably did in in 1985. Can you think of any others?) And Labour's plight is so dire that it may well be that the party has passed the point of no return, and that there is nothing Brown could say that would make any difference.

But you wouldn't expect Brown to accept that and, even if he doesn't believe in the "speech of his life" nonsense, he will know that this is a big occasion that could define the parameters of the general election campaign.

As usual, I'll be live blogging the speech (and as soon as a full text become available we'll be putting that up on the site too). And I'll be particularly interested in how he addresses the key challenges that he faces. As I see it, there are five of them.

The vision thing: Why does Labour want another term in office? Brown makes policy statements all the time, and we know exactly he's said about social justice etc, but he has never been able to give the public a compelling answer to this question. David CameronDavid Cameron's vision of a Conservative Britain in 2015 is a bit hazy. But it's a lot clearer than Brown's vision of a Labour Britain in 2015. The prime minister has got to find a way of explaining how his policies and values add up to something much bigger, a vision of the future that will appeal to the electorate.

Election tactics: Brown has often suggested that he deserves to be re-elected because of his record and because of his deft response to the banking crisis. But voters are an ungrateful lot and they don't write thank you letters. Lord Mandelson understands this, and he made this point explicitly in this conference speech when he said: "Remember that you win elections on the future, not the past." Will BrownWill Brown show us that he now agrees?

New policies: Vision alone is not enough. Brown also needs to flesh that out with some policies. And they need to be policies that are (a) likely to be popular and (b) hard for the Conservatives to match. We've been told that he's going to announce a crackdown on antisocial behaviour. This smacks of something that has been dreamed up to appease the focus groups, and it's hard to see how Labour will beat the Tories on antisocial behaviour. Brown will have to unveil a lot more than this.

David Cameron: The voters seem to like David Cameron and they are happy with the idea of him becoming prime minister. Brown has got to come up with a convincing reason why they're wrong.

Himself: Brown has been a powerful figure in British politics for at least 15 years, the voters know him well and all the evidence suggests that they now find him personally objectionable. This won't doom the Labour campaign on its own, but it doesn't help and it's an issue that Brown needs to address. Will he promise to change his ways, as he did when addressed the parliamentary Labour party at the time of the "attempted coup" in June? Or will he find a way of depicting his weaknesses as strengths?