The contrasting views, widely described by observers as an escalating and bitter row, relate to the nuanced dynamic shared by holders of the Commonwealth’s most senior law offices. In question is whether Mr Gleeson had been consulted about the way members of government could gain access to his counsel.

“I was not given an opportunity to comment on the content of the direction,” Mr Gleeson said in his written submission to the inquiry.

Signs of strained dealings between Senator Brandis and Mr Gleeson, who has held the role since 2013, had started to show earlier this year.

In May, ahead of the federal election and just before the dissolution of parliament, Senator Brandis tabled a written direction in the Senate.

By the directive, the solicitor-general was effectively blocked from advising any minster or government department without first obtaining written approval from Senator Brandis, including advice sought by either the prime minister or governor general.

The Senate legal and constitutional affairs references committee met last week to consider the direction.

Mr Gleeson said he was not consulted about the change, as spelled out in the legally binding Legal Services Amendment (Solicitor-General Opinions) Direction 2016. According to the solicitor general, he had even gone so far as to have the direction withdrawn in the hope that a proper consultation process could occur.

In his own submissions to the inquiry, Senator Brandis maintained that the Mr Gleeson had been consulted about the direction, pointing to a meeting held in November. 

Senator Brandis’ submission outlines that the direction merely “establishes a procedure that enables government bodies – not just the attorney general – to request solicitor general opinions by going through the attorney general.”

He added that correspondence with Mr Gleeson on 12 November, 2015 admitted insufficient procedures were in place to coordinate his advice to various government departments and agencies, which the direction sought to address.

“[The direction] does nothing to change the effect of the Law Officers Act. It simply establishes a procedure for implementing the reuqirements of that Act in such a way that allows other government agencies and bodies, rather than just the attorney general, to seek the solicitor general’s opinion on a question of law,” Senator Brandis wrote.

In his written submission, Mr Gleeson stressed importance that the solicitor general’s independence carried. For this reason the attorney general, acting as a gate-keeper to the advice of the solicitor general’s counsel, posed a problem.

“The independence of the solicitor general, as established by the Law Officers Act, is of exceptional importance. As independent of the Government of the day, the solicitor general is able to give frank and fearless legal advice, unencumbered by political or commercial concerns,” Mr Gleeson said.

He explained that given the solicitor general is required to appear on the government’s behalf for “the most important court matters”, the independent nature of the role garnered wide respect.

“Such is the respect for the independent advice of the solicitor general that the government or the governor general may realise the advice of the solicitor general or refer to having received that advice as a way of addressing concerns the Parliament, the legal profession or the public may have about a controversial legal issue,” Mr Gleeson said.

He also shared with the inquiry a letter sent to Senator Brandis in November last year. In that letter, Mr Gleeson suggested a false impression had been by the attorney general that the solicitor general’s advice was sought with respect to the government’s plans to revoke the dual citizenship of Australian citizens involved with terrorism

Associate Professor Gabrielle Appleby, a legal academic from the University of New South Wales, was invited to appear before the Senate inquiry and give expert evidence about the relationship between the first and second law officers.

Writing for The Conversation, the academic said that historically, an intentional tension had been built into the dynamic of attorney general and solicitor general.

“An inherent tension is built into the relationship between the attorney-general and the solicitor-general. The attorney-general is the minister responsible for the solicitor-general. But it is imperative that the solicitor-general can advise the government independently, including from the more political attorney-general,” A/Prof Appleby said.

At the same time, the attorney-general’s department also proceeded with the revision of a guidance note, which legal academics have observed as no longer including the circumstances when a solicitor-general’s advice should be sought.

“Gleeson has denied there was any discussion about a requirement to seek the formal approval of the attorney-general before seeking his advice. In contrast to the direction, the guidance note was not a legal instrument; it was not enforceable in any way,” A/Prof Appleby said.