A historian has lost her latest legal battle to force the public release of the so-called “palace letters” between the Queen and the governor-general who played a crucial role in the dismissal of former prime minister Gough Whitlam.

Professor Jenny Hocking described the ongoing secrecy about the dozens of letters between Buckingham Palace and Sir John Kerr in the months before the unprecedented 1975 dismissal as a “national humiliation”.

On Friday, two of three judges in the Federal Court dismissed her appeal against a decision that the “palace letters”, held by the National Archives of Australia, were personal communications rather than official Commonwealth records.

Professor Hocking – a Monash University academic and Whitlam biographer – was ordered to pay $30,000 in costs.

In the upheld decision, the same court in March 2018 ruled the letters didn’t have to be released as they were the personal property of Sir John.

Professor Hocking believed the letters would give insight into the then-governor general’s thinking and how much the palace knew.

In her appeal for donations to support her ongoing fight, she says the continued secrecy around the letters is wrong.

“It should not be for the Queen to decide when we can know and have access to critical documents in our own history,” she said.

“We all deserve to know the truth of the dismissal and what really happened at that time.

On Friday, Professor Hocking said she was disappointed for all Australians, who should have access to “such important historical documents”.

The letters are embargoed until at least 2027, but the Queen holds a final veto over their release.

“It’s more than 40 years since the dismissal of the Whitlam government and it’s extraordinary that we’re still waiting to see absolutely vital information about that dismissal of an elected government,” Professor Hocking said outside court.

“It’s a national humiliation that those letters remain embargoed by the Queen and yet they’re held in our own archive.”

She said she’d have to read the appeal judgment before considering “what our possibilities are going forward”.

-with AAP