Campaigners have added their voice to demands for the release of letters between the Australian Governor General and the Queen, dating back to 1975.
Academic and author Jenny Hocking is currently taking the case to court in Australia, seeking the release of letters relating to the 1975 dismissal of then prime minister Gough Whitlam.
As well as shedding new light on the events that led up to the controversial dismissal, the letters raise questions about the Queen's complicity in the affair.
Anti-monarchy campaign Republic, which is also calling for royal archives in the UK to be opened up, has said there are serious concerns about the monarch's involvement.
Graham Smith, CEO of Republic, said today:
"These letters raise questions about how much the Queen knew in advance of John Kerr's dismissal of Gough Whitlam as PM. If the Queen knew what Kerr was planning then serious questions must be asked about her involvement."
"The Queen and the Governor General are supposed to act on the advice of the prime minister. Did the Queen tell the governor general to warn the prime minister of his intentions? Did she warn the prime minister of what Kerr was planning?"
"If the Queen knew about Kerr's intention to dismiss an elected prime minister and did nothing, she is complicit in a controversy that has had a lasting impact on Australian politics."
"Kerr dismissed a prime minister who commanded the confidence of the lower house, and ignored a vote to re-instate the prime minister hours after the dismissal. It was a deeply damaging and unconstitutional affair - and the Queen needs to answer questions about her complicity."
In November 1975 Australian Governor General John Kerr dismissed prime minister Gough Whitlam. The PM was kept in the dark about the possibility of dismissal and was expecting to continue in office. Later that day parliament passed a vote of no confidence in the appointment of the opposition leader as prime minister and voted to re-instate Whitlam. Kerr ignored this vote and Whitlam's Labor government was forced out of office.
Research by Jenny Hocking has revealed the existence of extensive correspondence between Kerr and the Queen in the weeks and months leading up to the dismissal, which give ground for believing the Queen was aware of the plan but did nothing to advise or warn the prime minister.
The case is expected to conclude next month. Hocking sets out the issue in this article: The Queen and the dismissal: the palace letters are not 'personal' and must be released | Jenny Hocking