"Gordon Brown will be gone by the end of the week." This was the startling message I received late on 5 January from a senior former cabinet minister. But by the next day, it appeared unlikely, especially by lunchtime.
Labour MPs cheered Gordon Brown as he triumphed at Prime Minister's Questions. After David Cameron delivered a pre-rehearsed quip that when he says, "Darling, I love you," he means it - not so, Brown with his Chancellor - the Prime Minister hit back with an uncharacteristically spontaneous joke of his own about the Tory leader's U-turn on tax breaks for married couples: "He can't even say I do or I don't."
Little did he know, however, that behind him the same MPs who were smiling were discussing a secret ballot on his leadership. Late on the morning of Wednesday 6 January, word spread round the Members' Lobby that two former cabinet ministers, Patricia Hewitt and Geoff Hoon, were to break cover after PMQs with a statement calling for a vote of no confidence in their leader. The news that Charles Clarke, the rebels' leader, was being joined by two relatively big beasts rocked No 10.
During PMQs, some rebels had hesitated over throwing their latest grenade, partly because of the heavy snowfall across the UK and partly because of Brown's unusually assured performance. But they went ahead regardless and news of the secret ballot and the carefully co-ordinated coup, broken on Newstatesman.com, was the second major blow to Brown in a week that should have been a success.
After all, Labour had won the first round of election-year battling, when David Cameron performed his reversal on married tax breaks. Having first said they could not be guaranteed because of the scale of the Budget deficit, he caved in to pressure from the Tory right, an army ofConservativeHome bloggers and the traditionalist former leader Iain Duncan Smith.
Yet, while a number of MPs claimed that Gordon Brown would now survive this crucial month - the last chance for any internal coup - the rumblings continued. On 4 January, a rumour emerged that another cabinet minister was set to resign. The subject of that rumour, which began with a series of online messages, was the "Blairite" Olympics minister, Tessa Jowell. However, as we reported exclusively on our website, she had called Downing Street with the assurance that she was staying. "Tessa is in a good place with Gordon at the moment," said a well-placed source.
“The only real issue about the leadership now lies in the bunker itself," one supportive party figure said before the attempted coup on 6 January. "The plotters can't get their act together. The question is whether Gordon can."
On Wednesday however, Brown showed signs that he could, and the rebels' assault looked to have been badly timed.
Downing Street insisted this was simply "tearoom gossip" and dismissed the Hewitt-Hoon attack as "sour grapes from former ministers". Certainly, Hoon is an unlikely assassin and one who may resent his failure to become EU high commissioner. The reality is that Brown is still likely to be the leader going into the election.
The main problem no anti-Brown Labour figure has ever been able to solve is how there could be a second "smooth transition" of the leadership, a question that becomes more acute every day in the run-up to the election this spring. Lord Falconer, no fool, maintains that a contest - avoided in 2007 - would be "healthy". But he is practically alone.
Labour could implode into a full-scale leadership contest involving several or all of the following: David Miliband, Ed Balls, Harriet Harman, Jon Cruddas, Alan Johnson, Clarke and maybe Ed Miliband. Brown would not be in a position of strength to ensure a successor of his choice. And Balls would not tolerate that transition to any figure other than himself.
Instead, the only prospect of Brown's removal - which surely must, if it is going to happen, occur within the coming days - is for him to step down voluntarily. Some say that this would take a private appeal from that unlikely duo, Peter Mandelson and Balls, whose disagreement over what approach to take in the election is the only substantial strategic division within the Labour leadership. One MP wistfully floated the idea that Brown could "miraculously" be found a "saving the world" job such as head of the International Monetary Fund. The plotters whinge that the Labour movement should not go down because of the ruthlessness and political vanity of one man.
But, as one MP said, the cabinet has "no balls". This is unfair on David Miliband, for example, the most credible candidate to replace Brown before the election, who has judged that the carnage that would ensue from his resignation as Foreign Secretary would not be in the interests of the party. Were he - or Johnson - to change heart, Brown would surely be finished.
What remains clear is that there is nothing in the history or psychology of Gordon Brown that indicates he would have fought bitterly with Tony Blair for ten years, and endured such abuse as Prime Minister for two, to give up the chance of fighting a general election he still genuinely believes he can win. Indeed, he may be tempted to call that election imminently.
Brown has been rocked. His future is hard to predict. But unless a cabinet minister resigns, it appears he will, just, see off one last rebellion and survive this crucial week.