He may have made his fortune out of mobile telephony, but Mr Denis O'Brien knows that giving evidence before a tribunal is essentially a fixed-line business.
His line yesterday was that the Telenor donation to Fine Gael in 1995 was never anything to do with him or Esat. And although he experienced some difficulty getting through to the tribunal on it, he stuck with it throughout.
Counsel for the tribunal didn't think it was a very good line, and several times invited him to hang up and try again. At one point, Mr John Coughlan SC even appeared to suggest the line was out of order. But Mr O'Brien would not be shifted.
Matters came to a head when the witness spoke disparagingly of the "ring-a-ring-a-rosey" of invoices by which the Norwegian company had attempted to re-route the $50,000 donation back to Esat, disguised as consultancy fees.
Mr Coughlan didn't like this ringing tone. And when, soon afterwards, the witness suggested Telenor had "made" Esat take responsibility for the donation during negotiations on a shareholders' agreement, counsel finally cut him off.
He invited the witness to "reflect" on what he was saying. "We are in the world of serious business people now, not school children," he snapped. Mr O'Brien duly reflected and, for the only time yesterday, changed his line a little. Esat hadn't been "made" to claim the payment, exactly; the two companies had "agreed" this.
Not for the first time in Irish history, Norsemen were getting the blame for a lot of things - even if, apart from his "ring-a-rosey" jibe, Mr O'Brien's strongest comment was that the company's invoicing for the Fine Gael donation was "chaotic". To which Mr Coughlan replied drily: "It may be chaotic. It may be something else."
Mr O'Brien said he suggested Telenor as a possible donor to the Fine Gael fundraiser Mr David Austin, because it wanted to get involved in "Irish affairs". Did he mean just business affairs? counsel wondered. "Yes," said Mr O'Brien with a pause, "and to become more involved in Ireland".
The company has certainly achieved that ambition. Earlier, its chief executive, Mr Arve Johansen, resumed the witness stand to say that Mr O'Brien asked him to make the payment on Esat's behalf to avoid causing a "fuss in the media".
The sequence by which the money was paid into an offshore account and then reimbursed to Telenor seemed strange, he admitted. But: "A lot of firms and a lot of private persons in Ireland had onshore and offshore accounts. So in my mind I said: `Well, this is another one'."
Mr Johansen was going offshore himself by the time Mr O'Brien took the stand, chasing a flight back to Oslo. However, he has made one significant contribution to this inquiry. His first name has two syllables, with a stress on the final `e'. So when the ballad of the Moriarty tribunal finally comes to be written, at least we now have a word that rhymes with Charvet.
Mr O'Brien spoke of other political donations he had made "since my windfall 18 months ago".
The £230 million profit blown his way by the Esat sale was more like hurricane damage than a mere windfall. Yet, with all the stormy weather around him, Mr O'Brien has remained unflappable. True, at one point yesterday, he spoke of the need, prior to East's flotation, for "dotting all the Ts". But perhaps this was Norwegian punctuation.