Attorney-General George Brandis is embroiled in a matter so esoteric we can't afford the legal advice to explain it here. Credit:Alex Ellinghausen Fairfax Media can now reveal Senator Brandis sought the advice of former Commonwealth Solicitor-General David Bennett, QC, who served principally during the Howard government, on the same-sex marriage plebiscite after rejecting advice from Mr Gleeson. The Solicitor-General is second only to the Attorney-General in the hierarchy of law officers in the country. Their role is to provide independent, apolitical advice to government on matters of national significance and appear in high-profile court cases on behalf of the Commonwealth. Speaking generally, University of NSW associate professor Gabrielle Appleby said there was a risk that governments seeking opinions from lawyers other than the Solicitor-General might be "shopping around for politically convenient opinions and not accepting the opinion of the statutorily independent, apolitical Solicitor-General". "The Solicitor-General's opinions are usually treated as final and authoritative within government and that is for good reason," associate professor Appleby said.

Solicitor-General Justin Gleeson has flatly contradicted claims by George Brandis in Parliament that he consulted him about the change. Credit:Nic Walker "The Solicitor-General is a very senior, very experienced lawyer and . . . they have the protection of independence and status given by the statute." Dr Bennett, a respected senior counsel in Sydney, returned to the private bar in 2008 after serving as Solicitor-General during the Howard government and the start of the Rudd government. Days before the federal election, Senator Brandis issued a legally binding direction requiring all ministers - including the prime minister - to obtain his written approval before seeking the Solicitor-General's advice. Legal experts expressed concern the change was a power grab that restricted the independence of the Solicitor-General and reflected a breakdown in the relationship between the two men.

But Senator Brandis has said the change is purely administrative and is consistent with the law and historical practice, claims that are disputed by Mr Gleeson. In an explosive submission to a Senate inquiry, Mr Gleeson said he had not been consulted about the change, and would have opposed it "in the strongest terms" if given the chance. Mr Gleeson said there had been times since his appointment in 2013 when he had been asked directly by "persons, such as a prime minister or governor-general" to provide confidential, independent advice and it was "critically important" this should be allowed to continue. He wrote to Senator Brandis in November 2015, raising concerns the Australian Government Solicitor (AGS) rather than his office was consulted on a marriage equality proposal "under active consideration by the government". Mr Gleeson also said he was not consulted about significant changes to a proposal to strip dual nationals involved in terrorism of Australian citizenship. Senator Brandis later made public statements that Mr Gleeson had advised there was a "good prospect" the law would withstand a High Court challenge.

Senator Brandis insisted on Thursday the pair had discussed at length specific plans to reform the way the government sought Mr Gleeson's advice at a meeting on November 30 last year. "I've not misled the Parliament," Senator Brandis told ABC radio. "There were consultations. [The meeting] went for about an hour. The main topic of that meeting was this very issue." The sticking point between the men appears to be whether Mr Gleeson was alerted to the terms of a legally binding direction issued by Senator Brandis, or merely updated guidelines for briefing the Solicitor-General. A spokesman for Senator Brandis said: "It is not the practice of the Commonwealth to comment on the fact of, or the content of legal advice."

with Michael Koziol Follow us on Twitter