Letters written by the Queen before the 1975 dismissal of then Australian prime minister Gough Whitlam can be made public, an Australian court has ruled.
Mr Whitlam’s government was removed by her representative at the time, Governor-General Sir John Kerr, and replaced with an opposition party.
The dismissal is often described as the most controversial moment in Australian political history.
It is not known what correspondences between the Queen and Sir John contain.
More than 200 letters have been kept sealed in the National Archives, but on Friday the High Court of Australia ruled that a historian could access them.
Professor Jenny Hocking has long argued that they should be released as “Commonwealth records”.
The governor-general dismissed Mr Whitlam on the justification that he had failed to get parliament to approve a national budget then subsequently declined to resign or call an election.
It ultimately led to a general election that saw Malcolm Fraser’s centre-right Liberal Party – then acting as a caretaker government – come to power.