Denis O'Brien will be the sole witness at his High Court action in which he claims utterances in the Dáil about his personal banking arrangements with IBRC breached his constitutional rights.
The businessman alleges statements made in the house by Social Democrats TD Catherine Murphy and Sinn Fein's Pearse Doherty in May and June last year, interfered with his privacy and had a role in determining a pending legal action he had brought against RTE.
At the time of the utterances, O'Brien had already secured an injunction preventing the broadcaster from reporting on his banking affairs with IBRC.
In his opening submissions for O'Brien, senior counsel Michael Cush said: “Everything the case set out to achieve was undone by deputies Doherty and Murphy.”
This was because information relating to banking interest rates and agreements he had struck with IBRC, which O'Brien claimed was confidential, was put into the public domain while the case was ongoing.
He alleges Murphy was fully aware of the terms of the court injunction when she spoke out in the Dáil.
Cush said the case was “unique in the history of the State”, in that there had never before been a complaint that utterances in the Dáil had trespassed on the judicial domain.
He argued Dáil privilege could not be used to subvert the constitutional order and that if the court agreed with him, it was obliged to intervene.
“Unusually”, both sides in the case were relying on the doctrine of the separation of powers, he added.
The court heard that the telecoms mogul made three complaints about the utterances by Murphy and Doherty.
However, the Dáil Committee on Procedure and Privileges found the standing orders of the house had not been breached by either TD. Murphy was found to have acted in good faith.
O'Brien is suing the the committee, the clerk of the Dáil and the attorney general. He is scheduled to testify on Thursday. Cush said his evidence will be “very short”.
The case is expected to last between six to eight days before Justice Úna Ní Raifeartaigh.