John Rentoul: Vacancy: who wants Brown's job the most?

Either Cameron or some young Labour pretender will oust the Prime Minister from No 10. And he has no control over which it is

Members of a doomsday cult went into a cave in Russia in November to await the end of the world, which they currently have pencilled in for next month. They were joined by members of the British press – in spirit if not in body – who, since then, have been predicting doom, gloom and the end of capitalism as we know it. The end of capitalism, for most people's purposes, meaning the discovery that house prices can go down as well as up.

For four months, the newspapers have been full of the atavistic fears of the middle classes, starting with a credit crunch and the run on Northern Rock. A run on a bank is really a 19th-century phenomenon, out of reach of living memory. A few weeks ago, a slightly less distant spectre fleetingly haunted the front pages: that of the Depression. On 21 January, the London Stock Exchange lost 6 per cent of its value. But the next day it bounced back, and it is now roughly where it was to start with.

Last week, more recent terrors were exhumed. The words "negative equity" and "repossessions" finally spread beyond the pages of the Daily Mail, which has been trying to scare its readers with them for years. The decision by First Direct to suspend new mortgages confirmed the idea that something serious is going on.

It might be thought that this would be (more) bad news for Gordon Brown. He was an extraordinarily successful chancellor, even if a large portion of that success consisted of good luck. It is widely assumed that his run of luck in managing the economy has come to an end. I am not so sure.

It may be that a little bit of negative equity is just what the British economy needs right now. If banks have suddenly realised that 100 per cent mortgages might be a bad idea, or that it might be risky to lend to people who do not provide evidence of their income, might that not be a welcome adjustment? If house prices, which have more than doubled in real terms over the past decade, go down a little this year, would that be the end of capitalism, or its self-corrective strengthening?

As my esteemed colleague Hamish McRae has written, the economic situation now is unlike that of 1990-93: today, unemployment is falling and interest rates are low, even if it may be harder to take out a mortgage than it has been in recent years.

So it could be that Brown will be lucky again. After 10 years as chancellor of defying the warnings that his forecasts were too optimistic, he could be about to pull off the same trick as Prime Minister. But I do not think that it will be enough to save him.

The opinion polls since the Budget suggest that something important is happening. For those at No 10, what must be most depressing is that the Budget is a prime example of when the Government has the initiative – yet its effect seems to have been to drive the voters farther away. Instead of providing Brown and Alistair Darling with the chance to show that they are setting the right course for the country, the Budget crystallised people's doubts about them.

There is something more going on here than a shift towards pessimism about the economy. Which is why I am not convinced that, even if the siren warnings of falling house prices turn out to be unfounded, it will do Brown much good.

From Brown's point of view, the most alarming thing that has happened is that time has passed. He has been Prime Minister for 10 months now. Soon it will be a year. And in Downing Street, Stephen Carter, his new chief of strategy and principal adviser, is still struggling to prove that his appointment was worth the trouble it has caused. That trouble, in the form of a briefing war between the old Brownites and Carter's new guard, is the sort of thing that cannot easily be stopped once it has started.

Last Monday, Brown gave a speech to the private weekly meeting of Labour MPs, which the leader usually does once a parliamentary session. It would be untrue to say that he was heckled. But I am told that there were audible grumbles of dissent, of a kind that even Blair did not attract in his last dark days.

On Tuesday, he spoke to the Cabinet from a strategy paper – everything in Downing Street has the word "strategy" in it. Some cabinet ministers were irritated to read in the press that the document had been written by Carter. Which would not have mattered, had Brown been able to inspire them with a show of leadership. But it is becoming painfully obvious that he is incapable of such a thing.

I would not be surprised if Tony Blair were watching the trashing of a potentially benign legacy with mounting frustration. "He can't grind it out," says one Blairite, referring to Brown's usual way of bulldozing through problems. "He's got to grab the public by the lapels."

The Blairites do not believe that he can, but they remain horribly torn because they do not have an alternative leader.

More than two years ago, in January 2006, Blair said there were "lots of good young people coming up" in the Government, and he listed them in apparently random order: David Miliband, Douglas Alexander, Andy Burnham, James Purnell, Ed Balls, Ed Miliband, Pat McFadden ... But none of them was ready, 18 months later, when the moment came for Blair to give Brown his reluctant endorsement.

And where are they now? Only the elder Miliband – still – is a plausible candidate for the top job should Brown become, in the words of the Labour Party rules, "permanently unavailable". The only MP that has added his name to that list in the past two years is Liam Byrne, the immigration minister, but, like McFadden, he is not yet in the Cabinet.

Several Labour MPs to whom I spoke before this week's Westminster recess did not say so directly, but seemed resigned to defeat in 2010. One suggested that – although he did not want it – a hung Parliament might provide the only shock that would force the party to renew itself. I am not so sure.

You have to look back only to December to recall how quickly settled assumptions in politics can be transformed. Four months ago, Barack Obama was given a 30 per cent chance of the Democratic nomination on the spread-betting markets; and John McCain, on less than 10 per cent, was trailing Rudy Giuliani, Mitt Romney and Mike Huckabee in the Republican race. Politics can seem fixed for years, and then everything changes suddenly.

No one has yet emerged who could convince Labour MPs that they have a better chance at the next general election if they changed their leader. But two years is a long time, and next month's local elections begin to seem a high hurdle for Brown to clear.

One of the lines from Brown's Bournemouth conference speech, at the peak of his now-forgotten honeymoon, is going to come back to haunt him: "When people say to me, 'Would you recommend this job to anyone else?' I say, 'Not yet.'"

Brown is likely to rue a cruel paradox, not yet, but soon. He will defy the doomsday cultists of economic meltdown. He ought, by rights, to earn our gratitude for steering the ship of the economy through the straits of global turbulence. But electorates don't do gratitude. I think they are already thinking that, whatever his economic record as chancellor and, now, as First Lord of the Treasury, he does not cut it as Prime Minister. Control over how that plays out is slipping from his hands.

We are entering a phase when the initiative will pass to whoever most wants his job: David Cameron or one of the young pretenders around his own cabinet table.