Background: Sale of Caribbean mobile firm expected to net more than €1.5bn

Denis O'Brien plans to be busier than ever, if that is possible, in the coming few months. He is determined to get a top price for the Caribbean mobile phone company he owns and which may be worth something north of €1.5 billion.

The pan-Caribbean Digicel business is owned by Bermuda registered, Digicel Ltd, which in turn is 87 to 90 per cent owned by Mr O'Brien. Bermuda does not charge capital gains tax and Mr O'Brien is tax resident in Portugal.

Mr O'Brien spends a lot of time on his private Gulfstream jet, travelling between the Caribbean, New York, Portugal and Dublin.

He spends the time reading, writing notes and sending e-mails. With a Digicel initial public offer (IPO) approaching, and plans to move into the US telecoms market, Mr O'Brien looks set to be spending more time than ever in transit.

Yesterday morning, he told the Bank of Ireland court (board) that the growing demands of his international business interests meant he could no longer devote the time required to the "ever increasing demands of the court", according to a statement from the bank.

Deputy governor of the court of the Bank of Ireland is a very prestigious position and the appointment was one about which Mr O'Brien was reportedly delighted. He was appointed almost exactly a year ago, for a two-year term. His decision to give it up came as a surprise to the board, according to sources.

He has been on the board since 2000, the year he sold Esat Telecom to BT for €2.4 billion. He netted €317 million for his percentage of the company from that sale. This time, if the IPO goes ahead, he will net a much more satisfying percentage.

The sale of Esat Telecom pitched Mr O'Brien into the mega-rich league and he has grown steadily richer ever since.

However, his Esat adventures led to controversies that brought negative publicity, which he said has damaged his reputation here and abroad. In that context, the sudden resignation from the Bank of Ireland is all the more surprising.

The disclosure that he had moved tax residency to Portugal, and thus was not liable to capital gains tax on his Esat windfall, created much negative comment. Then, in 2000, the Moriarty (Payments to Politicians) Tribunal began investigating possible payments by Mr O'Brien to Michael Lowry.

Mr Lowry was minister for Transport, Energy and Communications when Mr O'Brien won the 1995 mobile phone licence competition. He was also involved in overseeing the deregulation of fixed-line telecoms when Mr O'Brien was competing with Eircom.

The tribunal's inquiries led in turn to a lengthy and detailed inquiry into the mobile phone licence competition. Reports on these issues from the tribunal are expected sometime in 2007.

In 2001, Mr O'Brien locked horns with Sir Anthony O'Reilly over who would buy Eircom. The prize went to the older tycoon.

Mr O'Brien is known to have taken offence at some of the coverage he received of his affairs and his visits to the Moriarty tribunal in the O'Reilly-controlled Independent News & Media newspapers, so it was again a great surprise when, last January, he spent nearly €56.5 million buying a 3 per cent stake in the newspaper group.

His intentions remain unclear, but a medium-term aspiration towards gaining a controlling interest cannot be ruled out.

Meanwhile, he runs his Communicorp radio group, with stations here and across Europe. His Newstalk 106 station is due to go national in the coming weeks.