Commentary: Face it - only Miliband can save Labour now

This weekend we experienced the start of a carefully co-ordinated process that could see Brown out of office within weeks. The very fact that the MPs who started the ball rolling are little-known should worry Downing Street all the more.

The significance won't be lost on Mr Brown himself. Nobody outside the Westminster Village had heard of Chris Bryant or Tom Watson but they fired the opening salvos that forced Tony Blair out. Sending unlikely combatants over the top worked first for Gordon Brown, as it may yet for his opponents.

Had the "Brown Must Go" standard been waved yet again by the likes of Charles Clarke, most Labour MPs would have barely registered. Instead they saw decent, normally loyal backbenchers make the case for a change of leader. And it's the ordinary backbenchers making up the bulk of the parliamentary party who will ultimately decide whether Brown stays or goes.

The No 10 counter-attack had three prongs. One, the rebels don't count for much. Two, there aren't enough of them. It would take at least 70 to force an election. And three, they don't have an alternative leader ready to stand. Wrong on all three counts.

The first I have dealt with. As for numbers, there's no doubt that more than 70 Labour MPs would prefer a different leader. Some will make themselves known throughout this week. Others hold ministerial jobs from the Cabinet down. They are ready to make their move if and when the rebellion gathers sufficient strength.

So what about the third claim, that there is no alternative leader to hand? Balderdash. David Miliband has already set out his credentials and many find them convincing. Jack Straw and Harriet Harman have sent out signals that they would be ready to run. Had they wanted to squash the speculation stone dead they could, but they haven't.

The only denial from a politician worth taking seriously is along the lines of "I swear on my mother's grave that under no circumstances whatsoever will I ever support any other candidate than Gordon Brown and nor will I ever be one myself." When Miliband says that "of course" Brown will be leader at the next election and that he doesn't agree with the need for an election now, it falls some way short of that.

So will the time come any time soon? The odds on Brown going have shortened significantly in the past few days. What we're witnessing is not a few eruptions of isolated discontent but the playing out of a carefully planned strategy based on party rules. Which is more than can be said for the coup that put Brown in power.

Many Labour MPs have concluded that ditching him is the only way to prevent a Tory landslide at the next election. Many others have come to the opposite view. The third group is larger than either of the first two. It's made up of those who are genuinely torn as to the best way forward or who refuse to say which way they're leaning.

One question they should all be asking themselves is, "What is David Cameron hoping for?" Putting yourself in the shoes of your real opponent is always an excellent discipline and can often be the shortest route out of a difficult conundrum.

It seems to me that Cameron will be praying desperately for Brown to survive but so damaged by the affair that any lingering hope of him making a political recovery is gone forever. What Cameron will most fear is a new, purposeful Prime Minister able and willing to take him on at his own game. My bet is that he sees David Miliband as that man and there's no doubt the Foreign Secretary has the mettle, the ideas and the stamina for the job.

So Miliband would start any leadership election as the man to beat, which is not the same as being the favourite to win. To some he's too much the "Blairite". If Brown goes the party may be so traumatised that it opts for a "unity" figure like Straw or, if he can be persuaded to stand, Alan Johnson. That would be a mistake. Labour needs someone to take the fight to the Tories without holding back. A leader to inspire the country not one to soothe the party.

The time for procrastination is over. First Labour MPs must decide whether the Prime Minister can lead them back to a winning position. If enough of them conclude, as surely they must, that Brown isn't going to beat Cameron, it will then be for the party as a whole to decide who can.

Lance Price is the Labour Party's former communications director.