The Queen with then Governor-General Sir John Kerr in 1977

The Queen was not informed in advance about the 1975 dismissal of Australian Prime Minister Gough Whitlam, newly released letters show.

Mr Whitlam's government was removed by her representative at the time, Governor-General Sir John Kerr, and replaced with an opposition party.

It is considered the most controversial event in Australian political history.

The letters, released after a court battle, show Sir John wrote it was "better for Her Majesty not to know".

However, in earlier letters he had discussed with Buckingham Palace whether he had the constitutional authority to dismiss the prime minister.

Australia is a constitutional monarchy with the Queen as head of state, but many Australians previously had little idea her representative had such power.

Historians have since questioned what the palace knew about the removal of Mr Whitlam, a progressive whose reforms divided Australia after two decades of conservative rule.

• Obituary: Gough Whitlam
• Five ways Whitlam changed Australia

More than 200 letters kept sealed in the National Archives were released on Tuesday for the first time.

In May, the High Court of Australia ruled they could be accessed in the national interest following a challenge by historian Prof Jenny Hocking.

What happened to Gough Whitlam?

Mr Whitlam and his Labor Party came to power in 1972, implementing policies which many celebrated, but he grew less popular amid a troubled economy.

On 11 November 1975, he was sacked on the justification that he had failed to get parliament to approve spending and then subsequently declined to call an election.

Gough Whitlam raged against his sacking in 1975

The governor-general argued he had the authority to do this under implied powers in the constitution.

But this "reserve power" to remove an elected prime minister who held a majority in the House of Representatives has been debated ever since by legal experts.

His dismissal was an unprecedented action which shocked the country and prompted questions about Australia's political independence from Britain.

Some viewed it as a "constitutional coup" and an overreach of the "royal prerogative", speaking demonstrations and calls to become a republic.

But others celebrated his departure. In a general election held soon afterwards, voters overwhelmingly elected the caretaker government of Malcolm Fraser's centre-right Liberal Party.

Why is releasing the letters important?

Historians say they finally fill in the gaps about one of Australia's most crucial events.

"They go to the very heart of Australia's constitutional independence," said Prof Mark McKenna from the University of Sydney.

Mr Whitlam and his supporters consistently claimed he was the victim of a conspiracy between Sir John and Mr Fraser to remove him from office. However, there were no formal accusations of interference directed at Buckingham Palace.

The public was denied access to the letters because they were deemed "personal" correspondence with the Queen, and subject to a royal embargo.

Prof Hocking launched a court case in 2016 to overturn that status, arguing the letters were critical historical records. She said their access should not be restricted by the rules of a foreign power.

The release of the letters was "a terrific outcome for transparency and history", she told the BBC.

BBC