“Mr Justin Gleeson SC is a person of the highest integrity and skill. His decision to end an impasse he believed contrary to the national interest is both selfless and honourable,” Mr Clark said.

The news that the barrister had made the decision to fall on his sword on Monday put an end to what was an unprecedented clash between the nation’s top legal officers.

The conflict reached its height earlier this month, as members of a Senate legal and constitutional affairs committee took aim at the Solicitor-General. Coalition MPs, in particular, used the forum to insinuate the Solicitor-General had strayed from his duty to the government of the day and that he had deliberately set out to humiliate the Attorney-General by providing certain letters to the committee as part of his submissions.   

Senator Brandis and Mr Gleeson disagreed on a range of matters before the committee, from whether the Solicitor-General was consulted about the direction, to whether the Attorney-General had misled Parliament about having obtained the Solicitor-General’s advice concerning key legislation.

The Solicitor-General, who was appointed to his office under a Labor government in 2013, defended his actions before the committee. He repeatedly underscored the statutory obligations of the Solicitor-General to the Commonwealth, and the independent nature of the position.

Those same principles have been highlighted by the LCA in its public statement following the fallout. Mr Clark stressed that the role an independent Solicitor-General plays in maintaining the rule of law is paramount. He went on to suggest that the very notion of the separation of powers depends on it.

“It is criticial that the legal advice which the Solicitor-General provides to government ministers and their agencies is frank, fearless and independent.

“Maintaining the independence of that office ensures executive decision-making is conducted within the confines of the law and the powers conferred upon the executive by the Parliament,” Mr Clark said.

The interrogation to which Mr Gleeson was subjected during the Senate committee inquiry raised eyebrows in legal circles, with many speculating that the attacks intended to force him out.

A hint of the tensions between Senator Brandis and Mr Gleeson first emerged in May, after a written Senate direction was tabled. The direction was seen by many as a measure to restrict access to the Solicitor-General’s counsel.

The Attorney-General released Mr Gleeson’s letter of resignation with a copy of his response and an accompanying statement on Monday.

In his letter, Mr Gleeson cited an “irretrievably broken” relationship between the first and second law officers. He indicated that his resignation was the only tenable “resolution to the impasse” he found himself facing.

“My decision does not amount to a withdrawal of any position I have taken in relation to matters of controversy between us, including before the Senate legal and constitutional affairs reference committee,” Mr Gleeson said.

“I trust that it will in fact better enable the Parliament to make an objective consideration of the issues I have raised, undistracted by personalities.”

The Attorney-General’s short response acknowledged the receipt of Mr Gleeson’s notice and thanked him for his service as Solicitor-General of the Commonwealth.

“I agree with the view, expressed in your letter, that in the circumstances this is the proper course for you to take,” Senator Brandis wrote.

Tom Howe QC will be acting Solicitor-General until an official appointment is made to replace Mr Gleeson.