EMILY BOURKE: We'll go straight to Canberra this lunchtime, where political fireworks have erupted at the Senate inquiry into the deteriorating relationship between the nation's two most senior law officers.

The inquiry is examining a new rule Senator George Brandis introduced in May, requiring that his written permission be given before Justin Gleeson provides legal advice to anyone else in the Government.

Mr Gleeson says he was not consulted, while Senator Brandis says he was.

Well, today Solicitor-General Justin Gleeson has clashed with Government members of the inquiry and revealed in detail how his advice was ignored and misconstrued by the Attorney-General.

Political reporter Tom Iggulden has been watching proceedings and joins me now.

Tom, some extraordinary scenes in Canberra today. Everyone appears to have dispensed with customary courtesies.

This all centres around a direction that George Brandis gave, requiring that his express written permission be given before Justin Gleeson can provide any advice within government. What's he had to say about it?

TOM IGGULDEN: Well, he's described it as an extraordinary and radical move by the Attorney-General that's turned its back on almost 100 years of legal and government precedent.

Now, we already knew that there was a wide margin of disagreement, if I can put it that way, between Justin Gleeson and the Attorney-General. But he's revealed today exactly how this direction, which was directed in May, has affected his day-to-day workings as the Solicitor-General.

And in fact, he spoke of just yesterday being approached by a member of the Government legal team, who is arguing a case before the High Court as we speak, looking for some legal advice from Justin Gleeson. And he went on to explain that he was put in a difficult position because this person who came to him did not have George Brandis' written permission to provide such advice.

And this is what Justin Gleeson said he did about that situation:

JUSTIN GLEESON: What I did yesterday was that I decided, because I have come to the view this direction is invalid, that in the interests of the Commonwealth I should conduct that conference with that senior lawyer, which I did.

The conference went for 90 minutes. And I have commenced work on an opinion to answer the draft questions the Attorney-General may be sending to me shortly.

That is what an efficient counsel would do.

Do I lie awake at night and think, reading this direction literally, the Attorney-General could seek an injunction against me to restrain me performing my office? I do.

EMILY BOURKE: That's Solicitor-General Justin Gleeson speaking there.

Tom, it's hard to ignore the tone and the fiery exchanges with Coalition members of this committee, who seem to be taking issue with whether Mr Gleeson has openly defied or, indeed, is overstepping his duties by criticising the Government.

What's been the response there?

TOM IGGULDEN: Well, let's go back to that remark just there by Justin Gleeson that he potentially could face an injunction from his boss, the Attorney-General. Now, that obviously is a huge matter.

He has also raised questions of the rule of law and his independence as Solicitor-General, so that understandably has not gone down particularly well with the Government Senators on this enquiry.

And they have been asking him whether it is really appropriate for him to be going out and making these sorts of statements: in particular, the submission that he provided to this enquiry only last week that has caused all sorts of ripples in the political sense, Emily.

And here's a bit of an exchange that Mr Gleeson had with Ian Macdonald, a Government Senator, over that matter:

JUSTIN GLEESON: That letter was doing no more than asking for a discussion about...

IAN MACDONALD: No, but...

JUSTIN GLEESON: No, no, Senator, please do not interrupt me.

IAN MACDONALD: Sorry. You are here to answer questions…

LOUISE PRATT: Senator Macdonald…

IAN MACDONALD: …not to go off on a tangent of your own. My question was: is it appropriate for you…

LOUISE PRATT: Senator Macdonald, I need to call you to order.

IAN MACDONALD: Well, Chair...

LOUISE PRATT: Senator Macdonald.

IAN MACDONALD: …you have to tell the witness that this is not an opportunity for him to express his bile about anything but simply to answer the questions put to him.

UNIDENTIFIED SENATOR: He is trying to do answer the questions. He is trying to do that.

LOUISE PRATT: Senator McDonald, I need to remind you...

IAN MACDONALD: Now the question was: was it appropriate for you to tell the world through a Senate committee, which you knew politically would end up in this, that you'd given advice on same-sex marriage and the Migration Act. Is it appropriate?

JUSTIN GLEESON: I don't accept the premises of your question. My conduct was appropriate.

EMILY BOURKE: That's Justin Gleeson there, speaking under questioning at that Senate inquiry.

Tom Iggulden is in Canberra and joins me now.

Tom, where to from here? I mean, we've heard from Malcolm Turnbull this morning who says that he believes that the Attorney-General, George Brandis and Justin Gleeson will be able to get along and work together in the future. We're still to hear from the Attorney-General himself, aren't we?

TOM IGGULDEN: That's right. He's due to appear in about 20 minutes or half an hour from now.

But there have been some other extraordinary revelations throughout the course of this morning's evidence from Justin Gleeson that is going to make that contention by the Prime Minister, I would think, a little bit harder to stick to.

For example, we have the revelation that Justin Gleeson spoke with the shadow attorney-general, Mark Dreyfus, during the course of the election campaign about these matters. There have been some more angry exchanges about that.

And he's also taken the committee through his advice that he provided to the Government last year over the legislation to strip dual citizens of their Australian citizenship if they have terrorist connections.

Now that advice, according to the Attorney-General, George Brandis, was that the High Court was unlikely to find that unconstitutional: that legislation.

But Justin Gleeson has said today that, in fact, that is not the context that he gave that advice; and in fact the legislation was changed at the last minute after he gave such advice and therefore that advice did not relate directly to that legislation.

So that is a very damaging thing for him to say and something that is going to make this relationship, which has already deteriorated, much harder to work with down the track, I would have thought, Emily.

EMILY BOURKE: Tom Iggulden reporting there in Canberra.