Buckingham Palace has torn up a deal agreed in 1991 which would have allowed letters dating from the 1960s between the Queen and the Governor-General in Australia to be released.
Support for the Royal Family is polarised in Australia with a sizeable section of the population in favour of the country becoming a republic with an elected head of state. In 1999 a referendum found 54 percent in favour of the status quo.
But the monarch’s latest move could well boost support for republicanism in Australia.
The Weekend Australian newspaper said it had requested access to letters between the Queen and Robert Casey, whose term as Governor-General of Australia stretched from 1965 and 1969.
The newspaper said it believed the letters would shed light on several key moments in Australian political history - including the retirement of Prime Minister Robert Menzies in 1966 and the mysterious disappearance of another premier, Harold Holt, the following year.
Holt vanished while swimming off the coast of the state of Victoria in December 1967 and persistent conspiracy theories claimed he was actually a Chinese agent who was picked up by a submarine and his drowning was faked. His body was never found.
In the wake of Holt’s death there was a fierce battle for the leadership of the ruling Liberal Party which was eventually won by John Gorton after the Liberals’ coalition partners, the Country Party, vetoed his rival Billy McMahon.
McMahon eventually took over from Gorton in 1971 but lost a General Election to the Labor Party under Gough Whitlam the following year.
In 1975 Whitlam was controversially sacked by the then Governor-General, John Kerr, triggering a constitutional crisis which is still highlighted by Australian republicans.
The Weekend Australian reports that in 1991 a deal was done between Buckingham Palace and the National Archives of Australia that letters between the monarch and her representative would be made public 50 years after the end of the Governor General’s term.
That would have meant letters between Lord Casey and the Queen being released in 2019.
But it now appears that Buckingham Palace has reneged on this deal and decided the letters will only be released five years after the Queen’s death and has even said they would retain a veto on some letters ever being released.
The 1991 deal also covered letters of Governor-Generals Paul Hasluck (1969-74) , John Kerr (1974-77), Zelman Cowen (1977-82) and Ninian Stephen (1982-89).
The decision has caused anger in Australia, particularly because it is feared letters which focused on the events surrounded Whitlam’s sacking might not be released in 2027.
Paul Singer, official secretary to the current Governor-General, David Hurley, wrote to the director-general of the National Archives, David Fricker and said “the privacy and dignity” of the Queen must be respected and releasing the letters could damage relations between Britain and Australia.