The jury in the trial of three former Anglo Irish Bank executives in Ireland over the alleged unlawful provision of loans for the purchase of shares has been told it is making legal history.

Sean FitzPatrick, 65, the former chairman and one-time chief executive of the now defunct bank, former finance director Willie McAteer, 63, and former chief financial officer Pat Whelan, 51, face a total of 16 charges each.

They are alleged to have arranged 451 million euros (£350 million) of loans for clients to buy shares in the bank in 2008.

The three men appeared before court 19 of the Criminal Courts of Justice in Dublin for a trial that is expected to last four months and be one of the longest and most complex criminal cases in Irish history.

The three former bankers have pleaded not guilty.

Opening the case for the prosecution, senior counsel for the State Paul O'Higgins told the court that it is the first time 15 jurors have been asked to hear a criminal trial.

Only 12 will be selected at the end of the trial to return a verdict.

"This is the first time that process has occurred in the history of the state," the lawyer told the jury.

"Obviously every one of you maybe, and I suppose every one of you on the balance of chance, will be among the 12 to retire but three won't and that may be a very frustrating thing for those who don't, but maybe it will be a liberating thing for those who don't.

"You are the 15 judges for every matter of fact in this case."

Vast amounts of technical and financial evidence will be put before the jury, with 24 million documents and 800 witness statements due to be examined.

FitzPatrick, of Whitshed Road, Greystones, Co Wicklow; McAteer, of Auburn Villas, Rathgar, south Dublin; and Whelan, of Coast Road, Malahide, Co Dublin, have been charged with 16 counts of providing unlawful financial assistance to individuals in July 2008 for the purchase of shares in the bank.

They are charged under section 60 of the Companies Act.

The alleged offence involved loans to the family of bankrupt former billionaire Sean Quinn, including to his wife Patricia and son Sean junior, and 10 clients.

Among the witnesses due to give evidence are the Quinns, former financial regulator Pat Neary, former Central Bank of Ireland governor John Hurley and businessman Paddy McKillen.

Other developer clients and former Anglo executives are also on the list.

The bank was ultimately nationalised in January 2009.

The Irish Government stepped in following commitments made the previous September under the bank guarantee scheme and the bailout cost 29 billion euros (£24 billion).

Anglo was subsequently rebranded the Irish Bank Resolution Corporation and then liquidated last year.