Denis O'Brien is due to face further questions by lawyers at the Moriarty Tribunal at Dublin Castle this morning.
Yesterday, the billionaire businessman launched a scathing attack on the inquiry, accusing it of operating a vendetta against him and of wasting millions of euros of taxpayers' money.
He said he never bribed former minister Michael Lowry for help in acquiring Ireland's first mobile phone licence and insisted that Mr Lowry had no involvement in his takeover of Doncaster Rovers Football Club in 1998.
Mr O'Brien also said he was taking a case to the European Court of Human Rights after failing to block the tribunal's inquiries in the Irish courts.