Few politicians have a reputation for honesty and, despite his protests to the contrary, the current Prime Minister is no different.

MPs are also far more likely than most to consider their colleagues talentless beneficiaries of dumb luck.

But consecutive leaks showing senior figures in his government view untrustworthiness as one of Scott Morrison’s most salient personality traits is going to cement the Prime Minister’s credibility problem.

Deputy Prime Minister and Nationals leader Barnaby Joyce was forced to apologise on Saturday for a text he sent less than a year ago, while on the backbench, saying Mr Morrison “earnestly rearranges the truth to a lie”.

Despite his own image problems, Mr Joyce is still regarded as one of the Coalition’s most effective communicators and his words will stick.

So too will the disparaging “psycho” comment attributed to former New South Wales Premier Gladys Berejiklian.

The former premier’s skills as a pandemic leader were rated more highly than Mr Morrison shortly before she resigned amid a corruption inquiry.

On Sunday night, a claim by another former NSW premier, Bob Carr, breathed new life into the story about the Berejiklian text messages.

Mr Carr named Defence Minister Peter Dutton as the cabinet minister behind the leaking of the message referring to the Prime Minister as a “complete psycho”.

Mr Dutton later dismissed the claims as “baseless”.

Earlier, Mr Morrison had spoken about the “brutal business” of politics on Sunday, as he insisted he now had a good relationship with his deputy.

“People get angry and people get bitter. Of course they do – that’s all of us,” he said.

“Barnaby and I are getting on with it.”

But as Coalition MPs steel themselves for this year’s opening fortnight of Parliament, they know it will take more than a revised character assessment from Mr Joyce to undo the damage to the government.

Polls ‘only going one way’

“When [French President Emmanuel] Macron was saying it, it was one thing,” said a Liberal MP who spoke on the condition of anonymity.

“When it’s Gladys [Berejiklian] and [NSW Minister] Matt Kean and his own deputy saying it, that cements it in people’s minds.

“A lot of this is stuff now outside our control. I’m sure Labor has a few more text messages up its sleeve.

“It has been a tough two months. We don’t know how this is going to play out, but the polls are only going one way.”

Campaign advisers concede that whether the Prime Minister is in fact unusually or prolifically mendacious is now besides the point.

The calculus of modern elections and changing voters’ perceptions borrows a line from Lewis Carroll: “What I tell you three times is true.”

And Mr Morrison’s honesty has been called into question far more often than that.

Macron’s bombshell

French President Emmanuel Macron branded Mr Morrison a liar in no uncertain times over negotiations about the future construction of Australian submarines.

Asked if he thought the PM had lied to him, Macron replied: “I don’t think; I know”.

Mr Macron’s private text messages appeared in the media soon after.

Tweet from @BevanShields

A bad reputation

Former prime minister Malcolm Turnbull told reporters at the G20 summit that Mr Morrison had “lied […] on many occasions”, and that he “always had a reputation for telling lies”.

Tweet from @thetodayshow

Destination unknown

Under fire in Parliament over an allegation his office had falsely briefed journalists that reports he was in Hawaii during the Black Summer bushfires were false, Mr Morrison suggested that he had texted Labor leader Anthony Albanese about his holiday and where he was headed.

He was soon forced to retract that statement after Mr Albanese quickly leapt on what he said was an elision of truth: “He did not tell me where he was going.”

Seventeen times

Mr Morrison denied ever calling former Labor Senator and recipient of generosity from foreign donors, Sam Dastyari, “Shanghai Sam”.

He was later found to have used it 17 times.

The Prime Minister said he had misheard a journalist who asked him about his use of the term.

“If the best that the Leader of the Opposition can drum up is that withering attack, then I’m sure there is a lot of optimistic people who sit on the backbench,” he said.

Tweet from @guardian

Can’t recall

When asked about the catalogue of lying allegations, Mr Morrison said he could not think of an instance in which he has lied in public life.

“I don’t believe I have,” he responded.

Whether or not entirely by its own design, Labor’s years-long effort to paint Mr Morrison as someone on bad terms with the truth has well and truly stuck.

On the eve of the first Parliamentary sitting week for the year, faced with historically low poll figures and an election just around the corner, the Prime Minister is in a terrible position.