The lead consultant to the 1995 mobile phone licence competition has said he believed the Moriarty tribunal had a "predefined theory" when conducting its nine-year and ongoing inquiry.
Prof Michael Andersen told the former government minister Michael Lowry he believed the theory was based on assumptions that were wrong.
The tribunal is preventing Mr Lowry from questioning Prof Andersen about his private dealings with the tribunal and his view formed in 2002 that it had a bias.
Chairman Mr Justice Michael Moriarty said counsel for the tribunal would like to enter the witness box to give evidence about allegations that have been made against them. But he said he was going to stick by his ruling on that questions could not be asked about the bias allegation.
He said this was because if he did so he would have to allow counsel give their evidence on the matter, and then adjudicate on it. However, it was a basic principal that a person should not be a judge in his own cause.
Mr Lowry, representing himself, repeatedly sought to question Prof Andersen about his private dealings with the tribunal and was told it was not in keeping with the chairman's ruling.
Prof Andersen said he believed the bid from Esat Digifone, which won the licence competition, was one of the best he had ever seen. The evaluation team had been "astounded" by the level of preparation in the Esat bid, including site options for masts and planning applications.
Mr Lowry asked if it had been put to him in private by tribunal counsel that these were "fictitious and false". However he was not allowed continue the point.
Asked if he had been surprised by the lack of expertise he experienced among the tribunal team, Prof Andersen said he was not. He said initially he had been asked by the tribunal if he would act as a consultant to it, and people who looked for a consultant were seeking assistance, so he could not say he had been surprised, as suggested by Mr Lowry.
When asked how his relationship with the tribunal had evolved, Mr Justice Moriarty stopped the question. Mr Lowry, he said, was able to understand his ruling even if "your only professional advisers who are present are other than legal ones".
Prof Andersen said he believed the competition was conducted in a fair and square manner and arrived at a result that was relatively clear. He asked how it could then be subjected to an inquiry that had lasted nine years? The only explanation was that there was a belief that wrongdoing had occurred.
He said his observation of the tribunal was that it had made errors up to the opening statement made by it last week. There was "a consistency of error" emanating from the tribunal, he said.
At the outset of the proceedings Mr Lowry's microphone was not working. When he sought to continue regardless, Mr Justice Moriarty interrupted to say the reporters in the press box could not hear him. "I'm surprised that they want to hear anything I'd want to say," Mr Lowry commented.