For a fleeting moment, as news of James Purnell's resignation broke on Thursday night, rebel ringleaders had dared to believe their time had come.
After watching the News at Ten, one leading dissident predicted then that a stream of Cabinet members would follow the Work and Pensions Secretary out the door today. Would it be Alan Johnson? David Miliband? Andy Burnham? John Hutton?
But the exodus of ministerial heavyweights never materialised and last night even the Prime Minister's bitterest enemies admitted the Cabinet reshuffle had bought him more time.
The rebels are now holding their fire until Monday when MPs return to Westminster after tomorrow's declaration of the European election results, in which Labour is universally expected to have performed dismally.
The expected rout in the polls – the party could limp in fourth behind the UK Independence Party in the popular vote – will be used by the rebels in an attempt to win support for a "Gordon must go" letter.
Some are also threatening to demand his resignation when the Prime Minister addresses the Parliamentary Labour Party meeting on Monday, while former Cabinet Ministers Alan Milburn and Charles Clarke are expected to speak against Mr Brown in two days' time.
Arch-Blairite Stephen Byers, the former Transport Secretary, speaking publicly for the first time about the leadership crisis, said that Monday could make or break Mr Brown's fortunes.
"I think on Monday Labour MPs will be considering a very important question – is Gordon Brown a winner or is Gordon Brown a loser? Can Gordon Brown lead Labour to an election victory when the general election is called or will he lead us to defeat?"
The plotters aim to spend much of the weekend assessing exact levels of support. They insist their plan remains to send a letter on Monday evening demanding Mr Brown's resignation if they can persuade 50 MPs to go public. One admitted it was a high hurdle to clear and added: "The letter will not be sent if we get 45."
One key figure in the rebellion claimed: "People from the centre of the party are firming up against Brown. Within the backbenches there's a majority of opposition to him." But he admitted: "The question is whether that can be focused."
Another said: "Many Labour MPs are convinced Gordon must go. He may have bought some time... but we will resume the fight on Monday."
The MP insisted they had received messages of support from scores of defeated Labour councillors who blamed their defeat on Gordon Brown's huge unpopularity with voters. But they have been reminded over the last 36 hours of the ferocity and determination of the team around Gordon Brown, with rumours circulating of dissidents falling victim to No 10's "black arts".
One dissident MP has been warned that there were as yet undisclosed embarrassing mistakes in his expenses claims; others report being variously dismissed as "maverick", "Blairite" and "hard-Left" by Brown loyalists.
Barry Sheerman, a veteran MP and select committee chairman who has called for a secret vote on Mr Brown's leadership, said senior members of his Huddersfield constituency party had been contacted by No 10 urging them to hold a meeting with the MP to discuss his remarks.
Two other MPs claimed they had been falsely named as plotters by Downing Street in an attempt to "smoke out" the conspirators. A briefing note sent yesterday to MPs by Labour HQ on how to answer difficult questions gives the go-ahead for them to pour scorn over James Purnell. It insists the "whole Cabinet" found his resignation "surprising and disappointing" and the "last thing they would have wanted to see".
It also encourages them to portray the outgoing Work and Pensions Secretary as politically naive by describing him as "still in the early stages of his career".
The rebellion fizzled rather that fizzed as a handful of backbenchers went public with their private criticism of Mr Brown. The Newcastle-under-Lyme MP, Paul Farrelly, said: "There have been too many mistakes and misjudgement over the last two years. In the interests of the country and the Labour party, I think Gordon must really consider his position."
Meg Munn, a former Foreign Office Minister, said: "He's done a great job on the economy, but other issues are not being put across well. We are not seeing the sort of leadership which I think this country now needs." She was followed by veteran left-winger Mark Fisher who protested: "There is no stability in the Government and the time is right for him to stand down."
Paul Flynn, the Newport West MP, turned to his blog to plead for Mr Brown to bow out. He wrote: "For the sake of the millions who benefit from the work of the Labour Party in government, we must select a new national leader."
Downing Street could draw comfort from the apparently random pattern of attacks on Mr Brown's leadership. They were also relieved that a new Cabinet was in place by the end of the day, locking potential troublemakers in place.
While Gordon Brown travels today to Normandy for the D-Day commemorations, his allies are preparing to contact those backbenchers they suspect are wavering in their support for the Prime Minister.
Their key message to potential dissenters will be that a change of leader now will lead to unstoppable pressure for a general election – and the near-certainty that they will lose their seats in a Labour meltdown.