Reports have emerged of Malcolm Turnbull attacking Tony Abbott on his leadership in an expletive-ridden rant after the pair attended a boozy Sydney function in 2014.
It was onboard a government plane returning to Canberra that night, 14 months before Mr Turnbull took the leadership from Mr Abbott, that he ripped into the then prime minister.
Three ministers and five Coalition staff members were on the plane, The Daily Telegraph reports.
The report claims sources say Mr Turnbull's attack included dropping the C-bomb on more than one occasion as he told Mr Abbott he should resign.
Mr Abbott, Mr Turnbull and cabinet ministers Julie Bishop, Joe Hockey and George Brandis were all on the plane returning from the The Australian newspaper's 50th birthday party.
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It was reported that Mr Turnbull's expletive rant occurred just before the group were about to disembark.
It was then that he called Mr Abbott a "disloyal c***" and said he was "hopeless", according to three sources on board the plane.
One source on board the flight, who did not want to be named, said Mr Turnbull’s comments were “belligerent”.
“Tony went in to get his bag from the PM’s suite and Malcolm badgered him in that corridor. That’s where it happened,” the source said.
“It was Malcolm in full flight. Angry, bitter, (saying) you’re f***ing hopeless, you’re a ‘f***ing c***’, you should resign. He got quite close to his face.”
Sources close to Mr Turnbull said there was a heated discussion over policy.
Mr Abbott was asked about the incident on Monday on radio 2GB and said “I didn’t talk about it then and I’m certainly not going to talk about it now”.
“Malcolm and I go back a long long way and there have been a number of milestones in our relationship, some good and some not so good."
A spokesman for Mr Turnbull said he does not use that sort of language.
Turnbull government making ground
Meanwhile, The Turnbull government has clawed back some ground on Labor in the latest Newspoll, while Malcolm Turnbull is still the preferred prime minister.
But Labor remains ahead on a two-party preferred basis for the 19th Newspoll in a row, nearly two years after Mr Turnbull cited the polls for ousting Tony Abbott as prime minister.
The latest Newspoll in The Australian shows the coalition rose to 47 per cent to Labor's 53, up from a previous 46 to 54 per cent, on a two-party preferred basis.
Despite his government's lack of public support, Mr Turnbull overall remains Australia's preferred leader, at 46 per cent to Opposition Leader Bill Shorten's 29 per cent.
Mr Turnbull replaced Mr Abbott as leader in September 2015, claiming at the time the loss of 30 consecutive Newspolls was part of his justification.
The acrimony between the two men has plagued the federal Liberal party recently and won't be helped by News Corp Australia report on Monday.
The report claims Mr Turnbull gave "a scathing, expletive-ridden assessment" of Mr Abbott's prime ministership in front of other cabinet ministers after a black-tie event in Sydney 14 months before Mr Abbott was dumped.