The Australian newspaper front page from 12th October 1975 reporting on the historic dismissal of the Whitlam Government on the day before by Governor-General Sir John Kerr.

Gough Whitlam on the steps of Parliament house, delivering his speech after his dismissal. On November 11, 1975, Whitlam intended to call a half-senate election to break a deadlock. When he went to seek the governor-general’s approval for the election, he was dismissed as prime minister, triggering a constitutional crisis. Picture: Supplied

Then Governor-General Sir John Kerr, left, with Prime Minister Gough Whitlam, in the 1970s. Whitlam did not believe Kerr would dismiss him, and Kerr did nothing to open the prime minister’s eyes to this possibility. Hocking has previously found evidence that Buckingham Palace knew of Kerr’s intention to dismiss Whitlam and was involved in deliberations. Picture: Supplied

Whitlam listens to Sir David Smith, private secretary to the Governor-General, on the steps of Parliament House, reading out the proclamation of the dissolution of parliament in 1975. Picture: Supplied

Doug Anthony, left, Sir John Kerr and Malcolm Fraser, after the latter was sworn in as prime minister. Picture: Supplied

Gough Whitlam and Queen Elizabeth II during the 1973 Royal Tour. The Palace letters may reveal what the Queen said to Kerr and whether she influenced his actions. There have always been questions surrounding what the Queen knew about what was going on in Australia. Picture: Supplied

Sir John Kerr escorts Queen Elizabeth II to her aircraft at Perth Airport in 1977. The Palace letters are made up of more than 200 missives, largely between the Queen’s private secretary and the Governor-GGeneral’s official secretary, between July 1974 and December 1977. Picture: Getty Images

Sir John Kerr doffs his hat to the Queen, while in the background a lone protestor holds a 11.11.75 placard in 1977. Picture: Herald Sun

Former High Court Chief Justice Sir Anthony Mason. Mason’s role in fortifying Kerr’s decision to dismiss Gough Whitlam remains a secret. Mason has confirmed having discussions with Kerr about dismissing Whitlam. Picture: Supplied

Prime minister Malcolm Fraser, front left, with Queen Elizabeth II, Prince Philip and Sir John Kerr (R) , in Canberra in March 1977. Prior to the High Court ruling that the letters are Commonwealth records and property of the commonwealth, the National Archives of Australia had argued the letters were personal communications between the Queen and the governor-general, so ought not be released. Picture: News Corp

Gough Whitlam, left, and Gordon Scholes, right. The former Speaker of The House of Representatives sent a letter on the dismissal to the Queen, a day after Whitlam’s exit. Scholes expressed his concern about Sir John Kerr’s actions -- not just for the dismissal, but also for appointing Malcolm Fraser as caretaker prime minister. Scholes requested that the Queen reinstate Whitlam. Picture: News Corp

Historian Jenny Hocking fought a four-year legal battle to have the ‘palace letters’ -- correspondence between former governor-general Sir John Kerr and Buckingham Palace before the dismissal of the Whitlam government -- released in full. Hocking argues the public deserves to know the full history of the greatest political and constitutional crisis in Australia’s history. Picture: AAP

Gough Whitlam holds up the original 1975 dismissal letter he received from Sir John Kerr, in Sydney in 2005. Picture: News Corp