Historian Jenny Hocking has says the extent to which former governor general Sir John Kerr continually wrote to the Queen, informing her of Australian political matters was "startling" and some of the communication was "scandalous".
"These are not appropriate conversations to be having between the governor-general and a member of the royal family, and it's very concerning that those conversations were had and that the Queen engaged and then further," Professor Hocking said.
After years of legal challenges, the National Archives finally released letters between Sir John and the palace, mostly directed to the Queen's private secretary Sir Martin Charteris.
Sir John informed the palace he had been considering the dismissal of Gough Whitlam's government in advance of making the decision in November, but did not inform the Queen of his decision until it had been made.
"I was of the opinion that it was better for Her Majesty not to know in advance," Sir John wrote in a letter on November 11, immediately after sacking Mr Whitlam and making Liberal leader Malcolm Fraser caretaker prime minister.
They were released after Monash University's Professor Jenny Hocking successfully launched High Court action.
Professor Hocking said the letters were mainly as she expected, but she would be taking more time to fully explore their contents and implications. She said the letters showed concerning correspondence from Sir Martin to Sir John about the use of reserve powers.
"I am surprised there was any discussion about reserve powers, that seems to be improper in that context," she said.
Professor Hocking said the volume of correspondence, as well as its detail about the political tensions and goings-on of the time, were not appropriate.
"The thing that has surprised me most in recent months as that came out of the court case, it was the number of letters, the fact there are over 200 letters and 1200 pages, is really extraordinary," she said.
"Normally a governor-general would be reporting to the palace, maybe only every year, maybe quarterly, to be sending this number of letters, does show that very close interaction between the palace and the governor-general at that time, over matters that were intensely and profoundly political."
Among the pages of letters include a handful in the lead up to the dismissal of Mr Whitlam on November 11, 1975, including Sir John bringing attention to the issue of possible dismissal as early as September of that year.
Sir John wrote long letters to Sir Martin, enclosing clippings of newspapers.
Sir John's letters to the Queen are long and detailed, updating her on conversations, personalities, tactics, and different ways the crisis might play out. The responses from Sir Martin are much more succinct, assuring Sir John his stories were of great interest to the Queen, but also making it clear the decisions were his to take.
Sir John had canvassed the idea of a parliamentary impasse many months earlier.
While in late September 1975, Sir John believed there was much bluff on both sides, by October 17, he was telling the palace, "The country is set on a collision course now of historic proportions".
He recounted a dinner for the Malaysian prime minister, where Mr Whitlam had joked, "It could be a question of whether I get to the Queen first for your recall or you get in first with my dismissal. We all laughed."
On October 20, he described Mr Whitlam as in an "exuberant, even euphoric, mood", but hardened in his determination not to cave in and call an election. He was facing pressure to act from the Liberal opposition, but appeared to be still biding his time.
He described the saga in light terms as "the local drama". "As with all such serials we must wait to see how the various political heroes manage next week. In the meantime I feel called upon, at this stage, to do nothing," he wrote.
But within a few days, he was again in crisis mode, writing on October 22, 23 and 24.
On October 27, Sir John wrote to the palace to say the crisis might come to a head by the end of November, when the government might well find itself attempting to govern without money, and he might have to consider dissolving the Parliament.
"I am remaining calm about it all and seek no 'man of destiny' role in all of this," he wrote.
On November 6, he tells the palace he had met Mr Fraser and Mr Whitlam, with Mr Fraser insisting he would go on denying supply as many times as Mr Whitlam attempted to send his budget bills to the Senate, and Mr Whitlam standing by his refusal to call an election. Public servants would be paid till the last pay period in November, Sir John wrote.
"The crisis is now a very serious one ... an important decision one way or the other may have to be made by me this month."
In a letter dated November 4, Sir Martin gave him more detailed advice than previously, telling the governor-general that while it was often argued that the power of the crown to dissolve parliament no longer existed, "I do not believe this to be true".
"I think those powers do exist, ... but to use them is a heavy responsibility and it is only at the very end when there is demonstrably no other course that they should be used," he wrote.
"I am sure you are right in taking the line that your crisis has not yet crossed the threshold from the political to the constitutional arena.
"Mr Fraser wants to believe it is already a 'constitutional' crisis because he wants you to bring about an election which he thinks he can win. If the tide of public opinion continues to flood against him, he may well modify his view and look for a way of retreat."
He told Sir John he was impressed with his skill, wisdom and impartiality, and finished, with, "The fact that you have powers is recognised, but it is also clear that you will only use them in the last resort and then only for constitutional and not for political reasons."
On November 5, Sir Martin wrote again, telling Sir John the Queen wanted it worked out in Australia, and while "anything you may do could indirectly affect the monarchy in Australia", as long as he acted in accordance with the constitution, he could not damage the institution.
He finished with a quote from former Canadian prime minister Arthur Meihen, who said the role of the governor-general was to ensure responsible government was maintained, the government was responsible to parliament and the parliament was responsible to the people.
Whether that was taken by Sir John as a sign of approval of any move to sack the prime minister is not clear, but it was apparently the last word from the Queen before the November 11 dismissal.
At the time Sir John had draft legal advice commissioned by the government at his request throwing doubt on whether the Crown's powers to dismiss a prime minister still existed. But that sat alongside other legal opinions that said it did, and the opinion of Sir Martin in his November 4 letter that the powers remained but only to be used as a last resort.
On November 11, Sir John wrote again to the palace, saying he had taken the decisive step and dismissed Mr Whitlam and appointed Mr Fraser.
Mr Whitlam had come to see him, telling him, "I shall have to get in touch with the Palace immediately."
"To this I replied that this would be useless as he was at that time no longer Prime Minister. I had already signed the document terminating his commission."
Sir John said he had made the decision without informing the Queen in advance because the responsibility rested with him.
"I should say I decided to take the step I took without informing the palace in advance because, under the Constitution, the responsibility is mine, and I was of the opinion it was better for Her Majesty not to know in advance, though it is of course my duty to tell her immediately."
The letter included three attachments: the dismissal letter to Whitlam, a legal opinion from the then chief justice Sir Garfield Barwick, and a letter from the then opposition leader Mr Fraser.
Archives director-general David Fricker also detailed to reporters at a briefing in Canberra a letter from Sir John to the Queen dated September 12, 1975.
"I'm also keeping my mind open as to the constitutional issues. If the Prime Minister and the Leader of the Opposition get into a battle in which the Senate has defeated the budget, the Prime Minister refuses to recommend a dissolution, my role will need some careful thought," Sir John wrote.
Sir John included a press clipping that explored the options of dismissal of the Whitlam government.
Mr Fricker said, "So on the 12th of September 1975, Sir John is laying this out."
The Queen's secretary, Sir Martin, wrote back to Sir John referring to the practice that if a parliament refused supply - legislation allowing money to pay for government - it was constitutionally proper to grant a dissolution of the parliament.
On October 2, after Sir John had met Prince Charles in Papua New Guinea and discussed his suspicion Mr Whitlam wanted to ask the Queen to remove him as governor-general, Sir Martin told him that if it came to that, the Queen " would have no option but to follow the advice of her prime minister".
Around this time, the Senate made its first moves to block supply and the budget bills bounced back and forth between the two chambers and Mr Whitlam was considering a half-Senate election.
On October 17, Sir John described these events to Sir Martin, including relaying that Mr Fraser was of the view the governor-general had the power to dismiss the government and force an election.
"I do not know what will happen, or what I shall end up by doing, but the country is set on a collision course now of historic proportions," he wrote to the palace.
Sir John informed the Queen, via Sir Martin, immediately on November 11 of his actions in an uncharacteristically short letter of just two pages.
On November 20, he sent a much longer explanation.
Dr Fricker said this gave an insight into the governor-general's rationale.
"For my layperson's eyes, it reads very much like quite a deliberately formulated judgment ... a full exposition of what went through his mind leading up to that point," he told reporters on Tuesday.
He urged people to read the letters and attachments to get the full context of the historical period, noting that even which press clippings Sir John chose to include gave insight into his thinking.
Most of the letters are between Sir John and the Queen's private secretary, although a few are directly addressed to the monarch.
They cover the full gamut of Australian political events during his tenure from 1974 to 1977.
Director-general David Fricker will get legal advice on whether private letters between Buckingham Palace and other governors-general were caught up in the decision.
But Dr Fricker had been so focused on releasing the letters surrounding the Whitlam dismissal that he hadn't had time to consider others.
"I do still continue to go through that judgment and have a look at how that impacts upon the other royal correspondence," Dr Fricker said on Tuesday.
- with AAP