Senior Labor figures are convinced they won’t be facing Malcolm Turnbull as prime minister at the next election. Their calculation is based on the survival instinct that is a primal motivating force for all members of parliament. It was the one that led Labor politicians to swallow their pride, hold their noses and at the eleventh hour dump Julia Gillard for Kevin Rudd in 2013. It was all about “saving the furniture”, which translates as their own seats in the green chamber.

When the government’s 28th losing Newspoll in a row came out on Monday the Opposition leader was asked if it made happy reading for him. Bill Shorten piously answered: “My opposite number has chosen to define himself by opinion polls; I define myself by my values and priorities.” But he couldn’t resist saying that what we have seen in the past month is “a chaotic and divided, incompetent and inept government”. You know the Coalition is in trouble when even the partisan hyperbole of its opponent rings true. It is an accurate summary of the shambles on show in the never-ending Barnaby Joyce soap opera compounded by an ugly outburst from one of the government’s most senior women, Minister for Jobs Michaelia Cash.

Turnbull’s failure to at the very least condemn his minister’s comments smearing on the basis of unsubstantiated rumour every woman in Shorten’s office made him look as bad as her. And this despite his championing of a woman’s right to a respectful workplace on the day he banned “sexual relations between ministers and their staff”. That episode alone could go a long way to explaining why in the latest Newspoll Turnbull slipped a further eight points to be statistically lineball with Shorten as preferred prime minister. That’s a 12-point drop over three polls, highlighting a worrying new trend for the Liberal leader.

Of course preferred prime minister is not an indicator of an election outcome – it is not unusual for a premier or prime minster to be preferred right up until the time voters dump them and their party. Victoria’s Liberal premier Jeff Kennett was an example of this. But this metric was for a long while a morale booster for Turnbull and his team. Now even that shield has gone and the PM is left languishing with Shorten in deep negative territory of disapproval.

The average of the three latest opinion polls has the government trailing by 6.6 per cent. It’s a gap that has been consistent since the 2016 election and, in fact, on a couple of occasions, has blown out further. There is now an inevitability that the 30th bad Newspoll benchmark will be reached next month. And Tony Abbott, for one, will not be letting his nemesis Turnbull off the hook.

Turnbull has let it be known he would quit rather than go to the back bench. This would trigger a very unwelcome byelection and would probably hasten the defeat the manoeuvre was designed to avoid.

Abbott greeted the latest poll with this observation on Radio 2GB: “It was the prime minister who set this test. And I guess if he fails the test, it will be the prime minister who will have to explain why the test was right for one and not right for the other.” No doubt Abbott remembers the political death sentence passed on him on the day Turnbull struck him down.

Turnbull told reporters: “The one thing that is clear about our current situation is the trajectory. We have lost 30 Newspolls in a row. It is clear that the people have made up their mind about Mr Abbott’s leadership.” That argument played very strongly in the party room. The choice before them was oblivion with Abbott or salvation with Turnbull. The switch nearly ended in disaster at the last election when 14 government MPs lost their seats. An angry and resentful Turnbull spent election night in a funk. When the final results were tallied he was weakened and left with a one-seat majority.

One of the numbers Turnbull counts on is Michaelia Cash, from the party’s reactionary right in the West. The prime minister simply cannot afford to alienate her. Every vote counts in the party room. Some Liberals fear Abbott will let himself off the leash and ramp up his criticism of Turnbull for his failure to deliver a government that a majority of voters find convincing or cohesive.

One of Turnbull’s key supporters, Leader of the House Christopher Pyne, tried to minimise the opinion poll benchmark on Adelaide’s Radio 5AA. He said there were “a lot more significant reasons why the leadership changed in 2015 than 30 Newspolls”.

“Thirty Newspolls was a symptom, but the truth is that Malcolm Turnbull has the support of the party room in a way that Tony Abbott didn’t have, so there is absolutely no clock ticking on anyone,” he said. “This is a reality of politics – it’s arithmetic.” One backbencher was unimpressed. “We’re getting to the point where that may have to be tested,” he said.

Labor’s Anthony Albanese, a regular Pyne sparring partner, says it has been a diabolical period for the government in the past few weeks. “We’ll take on whoever the leader of the Liberal Party, and therefore the prime minister of the day, is.” He may have to wait a little longer. But none of the options on offer – Home Affairs Minister Peter Dutton, Treasurer Scott Morrison or Foreign Minister Julie Bishop – hold any fears for Labor, according to one of their most seasoned campaigners.

Should the party room move against Turnbull, he has let it be known he would quit rather than go to the back bench. This would trigger a very unwelcome byelection and would probably hasten the defeat the manoeuvre was designed to avoid. Instead Turnbull is playing for time. At a business forum midweek, he said he could assure us that “there is no plan, intention or consideration given to doing anything other than having an election at the usual time, which will be in the first half of 2019”. By then he is hoping that the trajectory of the past 18 months will somehow be reversed.

Events of course can determine much in politics, along with luck. Turnbull has had precious little of it. Citizenship last year and Barnaby Joyce this year have drowned out any good news that could be gleaned from “the record 403,100 new jobs created in 2017”. Furthermore, poor political management on his part has made matters only worse. Joyce’s use of the word “inept” resonated because it fits the bill so well. Compounding the degree of difficulty is the palpable disunity in the ranks of both the Liberal and National parties – something dramatically highlighted by the spectacle of two brooding sacked leaders on the back bench.

Joyce last weekend showed the “appalling judgement” Turnbull accused him of by raising doubts about the paternity of his partner Vikki Campion’s baby. He then turned up at a television doorstop on Monday to say it was none of anyone’s business and walked off as journalists shouted questions at him to clarify the situation.

While that unedifying circus plays out, Turnbull is ramping up his “kill Bill” strategy. He has seized on Shorten’s handling of the Adani mine issue to accuse the Labor leader of duplicity and saying one thing in Queensland and another in Victoria. In this he has been helped by at least one unnamed Labor frontbencher telling Sky News “Shorten had gone off the reservation”. This has fuelled speculation that destabilisation of Shorten has begun – a narrative the Liberals have been unsuccessfully pushing for months. They often taunt Shorten in parliament that Anthony Albanese is coming for him. If it is true, “Albo” has little support in caucus for a messy lunge at the leader that would first need a change of rules for him to do it.

There is no real sense to it at the moment other than vaulting ambition. And there is no appetite in caucus to accommodate that at the expense of party unity. That is not to say everyone in caucus or shadow cabinet thinks Shorten could have handled the Adani issue better. It is true that since the last election Shorten has hardened his stand on the mine. He always said it had to stack up financially and environmentally, but in 2016 he hoped it would. He now says he’s lost faith in the project, apparently without taking that change to shadow cabinet. He explains this position by saying “27 banks and financial institutions won’t fund it” and that “it has missed seven deadlines”. If you believed the company, he says it would have been exporting coal from the mine three years ago. He attacks Adani and its supporters for peddling false hopes of thousands of jobs as a cruel hoax on the people of north Queensland. It’s an argument Labor claims is beginning to bite.

Shorten’s stronger rhetoric against Adani is clearly in the context of the threat the Greens are posing in the Batman byelection. But despite Turnbull’s claim that Shorten would risk billions in compensation by closing the project down, he has no such intention. Shorten says he is aware of sovereign risk and will respect the lawful processes that have cleared the project to go ahead – if it can. This private project has the protection of the Howard government’s Environment Protection and Biodiversity Conservation Act that didn’t exist when Bob Hawke intervened over the Franklin Dam. It is something, according to Labor, the Greens conveniently ignore.

Whatever happens in Batman won’t boost the Turnbull government. The Liberals aren’t running and there is a strong argument they are increasingly on the wrong side of national sentiment about Adani anyhow.

The tumbrel will keep approaching.