It was the endorsement and backing he wanted. Labour MSPs, still reeling from the SNP's victory in the Holyrood elections, used a group meeting in Glasgow yesterday to heap praise on leader Jack McConnell. Many things needed to be discussed, it was agreed, but a fresh face at the top wasn't on the agenda.

But while many of McConnell's colleagues appear to be behind him, several do so with daggers drawn. One Labour MSP believes the "top priority" is to elect a new leader in Scotland, while a senior party figure says McConnell is a "dead man walking".

The reason for the plotting is Labour's narrow defeat to the SNP, a trauma party strategists are trying to downplay. McConnell has so far failed to heed the convention of congratulating the election winner, in this case Alex Salmond, while one of his aides referred to the SNP win as akin to a "toss of the coin".

However, while McConnell's post-election phone call to the Nationalists seems to have been delayed, his party's post-mortem is under way. Who, activists are demanding to know, lost Scotland?

Much of the focus will centre around the "three camps" that ran the campaign. One was referred to as "the bunker", which included McConnell and his two advisers. The second revolved around John McTernan, the de facto campaign chief who represented the interests of Downing Street, while the third group was headed by the Brownite Scottish secretary Douglas Alexander, who kept his patron informed of developments.

One insider said the structure of the campaign "never worked" because of poor pre-election planning. A daily morning conference call, designed to co-ordinate Labour's strategy, was hamstrung by the fact the three "clique heads" were based in different cities: McConnell in Edinburgh; McTernan in Glasgow; and Alexander in London.

Labour's campaign was, as one party insider put it, like trying to run up Ben Nevis with lead boots on. An early poll showing the Nationalists 10% ahead was followed by a stream of surveys that gave the SNP credibility, confidence and, most importantly, momentum.

A run of gaffes also inhibited a successful Labour campaign. In the first week, a high-profile "briefing" by Blairite pollster Philip Gould was overshadowed by his admission that Labour were behind in his own internal poll.

Days later, the party scored another own goal after an "exclusive" screening of its new election broadcast revealed Labour were dressing up former party officials as "working families".

Even simple tasks such as organising endorsements seemed too difficult for the people's party. A business letter backing Labour was pulled when nobody could be persuaded to sign it, while ex-royal aide Michael Shea complained after the party unveiled him as a supporter, without his permission.

By the last week of the campaign, frustration had turned to desperation. Gordon Brown, the prospective PM, was calling journalists to give them the mobile phone number of Scotsport commentator Archie Macpherson. By calling him, the chancellor said, the lucky hacks would get a positive quote on the union. Days later, Labour lost Scotland.

But it is the cocktail of policy and personality clashes that explains Labour's disastrous campaign, say insiders. On strategy, both Brown and Blair believed an anti-SNP approach would win support, while McConnell favoured an upbeat message focusing on education and skills. The dispute, according to campaign sources, was never resolved Even the message on the union was said to be contradictory. The two architects of New Labour, despite their many differences, believed in homing in on the consequences of breaking up Britain. McConnell, by contrast, wanted to concentrate on the union's positive aspects.

"Imagine a car where every passenger is trying to get his hands on the wheel. That was the Labour campaign," said a senior campaign source.

Such tensions were less important than the personal grievances under the surface. Brown, who collects grudges like a philatelist acquires stamps, has never forgiven McConnell for backing Blair as party leader in 1994, and struggles to hide his contempt for his colleague.

McTernan, by contrast, mistrusted McConnell for the way he behaved in former first minister Henry McLeish's administration, while Alexander's loathing of the Motherwell MSP is neither concealed nor denied. Put in the mix a collection of aides who owe their loyalties to Brown or Blair, and a potent mix of personal hatreds was left stewing in John Smith House.

"Philip Gould was taken aback by the situation," said one source. "He said, There aren't two people up here who get on. They all hate each other's guts.'"

Labour's rushed policy on council tax, which was to create an extra band at the top and bottom of the property market, is said to illustrate the farcical nature of the party's election campaign.

Tom McCabe, the finance minister, had put together a proposal which was greeted with derision by McConnell and dropped days into the campaign. It is said the Scottish Labour leader, in a joint effort with one of his advisers, drafted a new policy on the eve of the manifesto launch, but told nobody.

"It wasn't even written on the back of a fag packet. It was a Google and pizza job," said a Labour campaign source. "It was then sprung on everyone with no facts or figures to back it up."

But these tensions were nothing new; indeed, they were a microcosm of the frustrations and back-biting that had been building up for months.

At the party's Oban conference the previous year, one Labour minister was overheard saying Brown would "assassinate" McConnell, even if he recorded a narrow victory at the Scottish election.

Months later, an ally of the chancellor expressed glee at McConnell being questioned by the Metropolitan Police about cash-for-peerages. He said the first minister had been "badly damaged" by the routine interview, before touting Wendy Alexander as a successor.

The bitterness infecting the Labour campaign turned septic at a strategy meeting early this year in London. Attended by McConnell, Brown and Blair, as well as their advisers, it was meant to iron out the differences in approach hampering the pre-election planning. According to one insider, McConnell made a presentation in which he called for a positive campaign strategy based on education, rather than focusing on independence. He also wanted to replace McTernan, then knee-deep in cash-for-peerages, as campaign chief.

The initial response to McConnell's pitch, said one Labour source, was "total silence". Blair is said to have "taken apart" the presentation, while Brown picked at the bones of the first minister's speech. Gould is understood to have winced at McConnell's "humiliation".

Worse was to follow. Steven Lawther, the party's head of communications and spin doctor, walked out of his job weeks before the start of the campaign. Party officials said he quit for "family reasons", which party insiders clarified as "Labour family reasons".

The election post-mortem will inevitably descend into a blame game, with the outgoing prime minister being lined up as an obvious fall guy. Several MSPs contacted by the Sunday Herald said Iraq, cash-for-peerages and other "UK issues" set Scottish Labour up for defeat.

McConnell is also likely to pin the blame on Blair and Brown, whom he believes were more obsessed with fighting each other than saving Scotland. But it is McConnell who is expected to take the flak for losing Scotland. Why, asked one Labour MP, if "UK issues" led to the defeat, did Labour win in Wales? "What was different about Holyrood?" he asked.

The views on McConnell from within the Labour camp are brutal. One senior campaign aide said his TV performances were "bloody awful", and added: "There was contempt for him within the team. People were pretty open about it. He was just no good."

Part of this antipathy stemmed from McConnell's perceived inability to stick to Labour's anti-independence line. According to one member of the inner circle, the first minister failed to carry out the instructions agreed by his party's fragile coalition.

"He would go on radio or whatever and just not be convincing about the Nationalists' case. He would want to talk about his so-called achievements, which were almost non-existent," he said.

THIS frustration was keenly felt by the Westminster-based campaign chiefs, McTernan and Alexander. By the end they resorted to an old trick to keep McConnell out of the way: pack him off on the Labour battle bus. A tactic used to marginalise Donald Dewar in 1999 was recycled in 2007.

But the anti-McConnell feeling had deeper roots than a four-week election campaign and extended beyond the usual troublemakers. In fact, many of the Scottish Labour leader's detractors sat next to him in his Cabinet.

The problem with McConnell's leadership, say the critics in his own group, was his inability to trust anyone outside his inner circle, namely special advisers Rachel McEwan and Douglas Campbell.

"Jack ran the Executive with two pals from his Stirling days," says one Labour politician. "Backbenchers and ministers were sidelined, while two nonentities controlled access to him."

McConnell's fifth anniversary in the job last year encapsulated these frustrations. Instead of marking the event with a series of articles and helpful suggestions to the media, team McConnell dropped the ball by failing to organise any substantial coverage.

"It was typical of the missed opportunities of Jack's five years," said one source. "He had a great chance to talk himself up, which he was in desperate need of doing, only for his clique to not bother."

McConnell's dependency on his two advisers also raised eyebrows. Brownites and Blairities, used to dealing with first-class political operatives, found themselves working with "second-rate" apparatchiks for whom they had little respect. On McEwan, who was said to be responsible for her boss's D-Day gaffe, another source said: "She was supposed to be Jack's brain, but I wouldn't have sent her out for a loaf."

It is said McConnell, furious at having lost the election, is now struggling to keep his dignity. His bizarre statement on Friday, rather than congratulating Salmond, claimed the SNP had no "moral authority" to pursue its policies.

However, McConnell is likely to be gone in months, if not weeks. MSPs Andy Kerr, Margaret Curran and Wendy Alexander are said to be circling him like vultures round a carcass. When Alexander's ambitions were revealed during the campaign, she described the report as "unsourced" and "malicious". One word not used was "untrue".

His only remaining card seems to be that Brown will do anything to prevent Salmond entering Bute House, even if it means accepting a Labour enemy as first minister. McConnell's career, once based on his independence, is now hanging by a thread held by one of oldest foes.