"If there is another challenge," Eric Abetz told him quietly and emphatically, "and Peta Credlin and Joe Hockey are still here, you will lose.'' It was as simple as that. The terms for Abbott's survival as prime minister were clear.

Many other colleagues gave him the same message. Another of his staunchest cabinet supporters, Andrew Robb, who had lobbied hard for votes for his leader in the spill, told Abbott that a lot of the colleagues had only voted for him on the understanding that he would make some changes, and the changes had to include replacing Credlin, Hockey or both.

"The point was made very clearly to him by a lot of us that the colleagues didn't think he could keep the job" if Credlin and Hockey kept theirs, says one of his most loyal supporters.

Abetz's advice was particularly well based. In systematically canvassing his colleagues for their votes on Abbott's behalf, he found that Credlin was the "number-one complaint" among Liberal MPs and senators, and Hockey number two, as he summarised to confidants.

Abbott was deaf to the advice; by the time he lost the job seven months later, he said he couldn't recall receiving it.

Indeed, the former prime minister has claimed since losing the leadership that not one of his cabinet colleagues ever came to him to tell him Credlin had to go. This insistence bewilders his fellow Liberals.

He resisted moving against Hockey until the very last day, when a second and fatal challenge was already in train, when it was too late. And sacking Credlin, his chief of staff, was never negotiable.

The woman that cartoonists drew as a 10-foot-tall, angry Amazon in leopard-skin print was, to him, the only truly indispensable member of the government, other than himself.

"He looked at his own death sentence," says an Abbott loyalist from his conservative faction, "and decided to accept it."

A dogged loyalty, often misguided, was a motif of the Abbott government. He persisted with policies and people well beyond the point of hopelessness. With his paid parental leave policy, with Bronwyn Bishop in her expenses scandal, with some harsh budget measures, and with Hockey and Credlin.

Ultimately, though, he was persuaded to abandon all. Except the last.

An Abbott minister concludes: "This is the first time in Australian history that a prime minister has been knifed not to get rid of the prime minister, but to get rid of his chief of staff."

The electric charge of the February revolt against Abbott also galvanised Malcolm Turnbull to think about the power structure for an incoming Turnbull prime ministership.

He was ready to move if the spill against Abbott succeeded. He prepared himself as momentum built, though his machinations were invisible to all but a few insiders.

Working with a handful of backbenchers, he was kept closely informed as they set up a system to keep tabs on the vote tally, with one head-counter appointed for each state.

Turnbull was coolly non-committal when colleagues approached him to run for the leadership.

But if he were to emerge as the new leader, he wanted to have his leadership team lined up.

On Sunday, February 8, the day before the February spill, Turnbull and Julie Bishop chanced to be at the same Liberal Party fundraising event in a private home in Sydney's prim Woollahra.

Stepping into a quiet room and closing the door, they discussed the situation. Turnbull took the opportunity to phone Scott Morrison.

Already in his car driving to Canberra from his home in Sydney, Morrison took the call. Speakerphone was engaged at both ends of the conversation.

It was well known that Morrison, then social services minister, had wanted the defence portfolio instead. Turnbull now wanted to know if he would be interested in the post of treasurer in the event that he should become leader.

A wary Morrison wanted to keep his options open and did not consider that he'd committed to anything during the call. It was, in any case, contingent on Abbott losing the ballot in the first place.

But Morrison did not reject the approach either. Bishop, too, was wary. She did not engage in the conversation but only listened. It was clear that Turnbull wanted her as his deputy. But Bishop wanted to keep intact her own option to run for the leadership.

Although the discussions were deliberately inconclusive, they nonetheless formed the basis for an understanding that remained tacitly in place as the trio continued to serve in the Abbott cabinet for the next seven months.

"We basically agreed – Turnbull as leader, Bishop as deputy and Morrison as treasurer," is how one participant summarised the conversation to a colleague. It was precisely this arrangement that became reality seven months later.

Abbott didn't know about the discussion, but he quickly sensed that Morrison had changed. He started making tough critiques of Hockey's performance as treasurer in internal conversations. It was soon the orthodoxy inside the Coalition that Morrison was gunning for the treasurer's job.

With the spill imminent, the backbench vote count was reported back to Turnbull. Of the 102 votes in the Liberal party room, 40 would be cast against Abbott, in favour of no one, he was told. The prime minister would win the other 62, a clear win.

Some backbenchers urged Turnbull to challenge regardless. But the communications minister was not interested in challenging to lose. He kept his counsel.

In the event, the result was 39 to 61, with one informal vote and one absentee. Abbott had been 12 votes away from losing the prime ministership to an empty chair, as one reader commented on a Fairfax Media website at the time.

Perhaps the most commonly uttered phrase in the Abbott government was "I'll check with the boss". This was not staff referring to the prime minister; it was the prime minister referring to his chief of staff, Peta Credlin. "She became utterly indispensable to him," a cabinet minister remarked, a view universally shared across the upper reaches of the government.

He was observed to turn away from conversations with heads of foreign governments with the words, "I'll check with the chief" or "I'll check with the boss", to consult Credlin on a point and then return to his foreign counterpart.

"Everyone around him was embarrassed for him," said a senior official who saw it happen more than once. "He seemed oblivious."

At the heart of the Abbott government was the relationship between the prime minister and his chief of staff, and it had an intensity that frustrated, infuriated and baffled many elected MPs and senators.

Credlin said after Abbott lost power that she refused "to be defined by insider gossip from unnamed sources where no one has the guts to put their name to it".

Barnaby Joyce puts his name to his analysis of Credlin. "She put herself at the centre, outside and inside the room," says Joyce, one of Abbott's closest friends in politics and the Agriculture Minister in the Abbott and Turnbull governments. As deputy leader of the National Party, he was also part of the government's inner leadership group.

For ministers who wanted approval for a proposal, "it was a two-hurdle race – you had to get Tony Abbott and Peta Credlin and line them both up," he told Fairfax Media.

"It creates real difficulty for a politician when they have to lobby someone who's not elected," says Joyce. "There was too much control from Tony's office."

Credlin's marriage to the federal director of the Liberal Party, Brian Loughnane, was another important source of frustration. "There was no check and balance," explains a junior minister in the Abbott team.

"Ordinarily, if you're having some issue with the prime minister's office – maybe he's visited one colleague's electorate 200 times and you can't get him to come to yours – you could go to the federal director and have it resolved.

"With this set-up, you felt you couldn't because it would be a career-limiting move."

It was a problem obvious to the organisational arm of the party as well as the parliamentary arm.

As the Liberal Party honorary treasurer, businessman Philip Higginson, wrote in a letter to the party's 27-member executive: "How this party ever let a husband and wife team into those two key roles, where collegiate competitive tension is mandatory, is a complete mystery."

He wrote that he was "overwhelmed daily by the sheer vitriol and pent-up animosities" that flowed from this "conflict of interest".

Among the 27 members of the executive is the prime minister. This letter was written for Abbott to see, and soon found its way to the media. It was written and leaked a couple of weeks after the February spill. The timing was not coincidental.

The tight-knit duumvirate model of governance might have suited the campaign-style structure of an opposition, but it ill-suited the administration of a national government.

In fact, one member of the Abbott cabinet, who opposed the February spill but voted for Turnbull in September, says: "I think there was a direct correlation between our effectiveness in opposition and our failure in government.

"We were so focused on bringing down the Labor government that we never created an alternative vision for the country. We had a laundry list – stop the boats and so on – not a vision.

"If Tony had led us to the next election, Labor would have said, 'We have a vision for the future.' We would have said, 'We've solved these problems – we've stopped the boats etc.' It was no match for the velocity of political events. There was a vacuum."

While this biggest of matters was left unaddressed, there was nothing too small, it seemed, for Credlin.

She personally decided the flower arrangements on the tables for the dinner for Germany's Chancellor Angela Merkel in Brisbane during the G20, for instance, as well as setting the prime minister's agenda for his meeting with her.

Perhaps the most commonly uttered phrase in the Abbott government was 'I'll check with boss.' This was not staff referring to the prime minister; it was the prime minister referring to his chief of staff

When Assistant Defence Minister Stuart Robert asked then air force chief Air Marshal Geoff Brown for an update on the refit of a KC-30 jet so it could serve as a VIP plane for the prime minister, he was told it had been taken out of the hands of the air force. Credlin was personally designing the reconfiguration, he discovered.

Whenever accused of micro-management, Credlin's riposte was to say that she could do the big picture and the small, the agenda of big policy for cabinet meetings and the minute details of the PM's personal appearances, because she put in the work. She boasted of doing 20-hour days, six days a week, and she was not exaggerating.

As Abbott's partnership with Credlin intensified, other sources of advice and influence were gradually shut out or ignored, notably the party's pollster, the blunt-spoken Mark Textor. He'd spoken weekly, sometimes more frequently, to John Howard in his prime ministership, as he does now to Turnbull. He was allowed no contact with Abbott for many months.

Even senior ministers with good relationships with Abbott and Credlin found themselves slowly excluded from the prime minister's inner counsels. "If you kept saying something that wasn't positive, you were left out of the inner circle, till there was no one left in the circle except Credlin," says an Abbott cabinet minister.

The broadcaster Phillip Adams quipped that Credlin was Australia's second female prime minister.

Which raises the question: What was the nature of the relationship between the co-rulers of Australia in the Abbott-Credlin years?

This story first appeared on The Age