A shadow minister nominated Mr Turnbull's Achilles heel as simply: "His big f--king ego." "He convinces himself that he is the smartest person in the room in every situation – and sometimes he is. But when you believe you are the only one who truly understands an issue it is pretty hard to listen to anyone else around you," said the source. "His big ego killed him before. What will his ego be like if he believes he is being called to the country's top job?" But the shadow minister also conceded Labor would have a tougher time opposing a Turnbull-led Coalition. "He's smarter than Abbott, more grounded than Abbott and he's an adult, unlike Abbott." Mr Turnbull is favoured as leader by twice as many people as Mr Abbott, a string of IPSOS Fairfax polls have found.

Another Labor source with experience of the Gillard–Rudd war said Mr Turnbull had weaknesses to exploit but said he would be a more formidable prime minister to oppose. "Absolutely he is more popular in the middle ground with voters, the place where elections are won," the source said. "This whole thing has reminded me of Gillard vs Rudd. A party stuck with a leader it knows cannot win an election and an alternative leader who is not liked by the party. But in the end, MPs will vote for their own survival, which is why I expect Malcolm Turnbull PM by mid-next week." Bruce Hawker, the longtime ALP campaigner who led Kevin Rudd's doomed bid for re-election in 2013, said Mr Turnbull would take the Liberal Party back to towards the centre ground but that would eventually expose divisions within his own party. "For Labor, Turnbull is a much harder character to deal with, he won't score the same own-goals that Tony Abbott has become famous for," Mr Hawker said.

"The danger for him is that he will start with a burst of popularity and relief in the electorate and he will try to steer his party back to centre ground. But he will have to deal with the Cory Bernardis of his party who are not going to sit back and watch a small-L liberal like Malcolm Turnbull do what he likes. That will open up the divisions for Labor to exploit." Opposition Leader Bill Shorten has been relegated to a low profile since the government began to tear itself apart after Australia Day, but his language at his daily press conference has begun to dig away at any notion that a change of leader would mean a fresh start for the Coalition. Mr Shorten said on Friday: "They all voted for the budget. On budget night when Joe Hockey and Tony Abbott brought down their budget, they were slamming the desks and cheering and that's the issue. "Malcolm Turnbull may wear nicer suits but he's just Tony Abbott in a nicer suit." On Tuesday he said: "They should stop worrying about which sales person they put up the front of the queue, and all of them should actually go back and take their foot off the throat of families."

A senior player behind Mr Shorten said there would be no great recalibration of strategy if a change occurs. "There's been a lot of talk about the effect of Turnbull taking over but we're actually not all that worried." Follow us on Twitter