Denis O’Brien sat in the witness box of Court 29 on Thursday and cast himself as Citizen Denis, champion of the people’s rights.

But it was the actual representative of the people – barrister Maurice Collins SC, appearing on behalf of Ireland and the Attorney General – who cut to the chase after about an hour.

The case that O'Brien's barrister, Michael Cush SC, was arguing on his behalf went far beyond seeking a judicial declaration that two TDs should not have allegedly breached an order of the High Court, or that the Oireachtas Committee on Procedure and Privileges failed properly to investigate his complaint about them, suggested Collins.

The May 2015 High Court order, or injunction, banning RTÉ from reporting on O'Brien's banking affairs with Irish Bank Resolution Corporation (IBRC) – the former Anglo Irish Bank – which he says was "undone" by Dáil comments from Social Democrats TD Catherine Murphy and Sinn Féin TD Pearse Doherty, was not the kernel of the matter.

Logical conclusion

O’Brien’s case was that any legal proceedings, at all, should be sufficient to make the Oireachtas fall silent.

“The case that is being put on your behalf,” said Collins in cross-examination, speaking directly to O’Brien in a clear, strong voice whose volume had risen a notch or two, “is that, the fact that you had pending proceedings was sufficient to justify this case. Did you know that?”

“If you’re saying that, it must be true,” replied O’Brien.

“The effect of issuing a writ is going to have an effect on Dáil speech, if you are correct?” asked Collins, seeking to draw what he assumed was a logical conclusion.

“If people breach a High Court order . . . ” began O’Brien.

But Collins pounced.

“No, no, no, no,” he said, cutting him off. “I’m not talking about High Court orders. Mr Cush has made it clear the order is significant but [that] without any order, without any order, this exact complaint could be ventilated by you. Merely having brought proceedings against RTÉ, that had never yet come to court, you could still bring these proceedings, according to your counsel. I am asking you – do you understand the effect of that, if you are right in that?”

"Yes, I do," said O'Brien.

“And the effect of that would be to greatly restrict Dáil speech. Isn’t that right?” said Collins.

“Yes,” acknowledged Citizen Denis.

Dumb mutes

The merest issuing of a writ, the faintest whiff of parchment winging its way to Kildare Street would be enough to turn the elected chambers of the people, the Dáil and Seanad, into dumb mutes.

About 100 people filled the courtroom as the injured plaintiff made his case, entering the witness box shortly after 11am.

He wore a mid-grey lounge suit, pale-blue shirt, matching dark-blue tie and well-polished, slip-on black shoes.

A large man in every sense of the word, he would look at home in any boardroom, anywhere.

The only jolt to his conventional appearance were the slightly zany, bright red-framed spectacles he donned, after swearing to tell the truth, to consult the written submission he made in support of his case.

He spoke in a soft but clear and self-assured voice, giving his direct evidence to Cush and spoke as a champion of the rights of the ordinary citizen, a defender of the Constitution, of the proper separation of the Oireachtas and the judiciary.

Ultimately, he was acting in the national interest.

“It would be a pretty extraordinary situation,” he said, “if the private details of a citizen’s banking arrangements were disclosed publicly” in an alleged breach of a High Court order and a mere two miles away, from the court, in the Dáil.

“It would be a very bad thing for the country to have a situation where people could rely on the courts [for an injunction] and for that to be unravelled by a different part of the country,” he said.

There could be implications for foreign investment.

“People would take a view, it would be a checklist of things you would view if you were investing in that country. It would be a weakness.”

Obfuscate

It is O’Brien’s contention that, in late May and early June last year, TDs Murphy and Doherty sought deliberately to subvert the proper separation of powers between the legislature and the courts by deliberately using Dáil privilege to reveal what he was trying to keep confidential (his banking interest rate deal with IBRC) through a High Court order, or injunction.

In giving evidence on Thursday, O’Brien wanted the High Court now to make adverse comment and make an adverse determination about the statements made by the TDs on the floor of the Dáil, wasn’t that so, asked Michael Collins SC, for the Dáil committee.

O’Brien paused and thought, before answering with a firm “Yes”.

They had "disrespected the High Court [order]", said the man who previously rained invective on Mr Justice Michael Moriarty ("he was never up to the job") and other judges ("the judiciary have put a ring of steel around him").

Maurice Collins adopted a combative tone in his cross-examination – not hesitating to cut O’Brien off when he was seeming to obfuscate.

“You’ve explained that,” said Collins, shutting him down and saying – pointedly – that he would “ask my question again”.

“The purpose of these proceedings is to have judicial condemnation of Deputy Murphy and Deputy Doherty for the utterances that they made in the Dáil?” asked Collins.

“Yes,” said O’Brien.

And moments later, after about an hour and 10 minutes giving evidence, it was all over.

“You are free to go,” said Ms Justice Úna Ní Raifeartaigh.

O’Brien gathered up his papers and ambled to the rear of the court where he sat listening for about 10 minutes as Michael Cush began wading through legal precedents at the start of several more days of submissions.

Moments later, the sole witness in the case slipped quietly out of the courtroom and into a waiting car.

O'Brien was whisked away to the sound of a Siteserv protester shouting abuse.