Businessman Denis O'Brien has begun an action for defamation against the Sunday Business Post over articles that he says portrayed him as one of the "developer kings" who destroyed Ireland and bankrupted its banks.

Mr O'Brien, 60, is suing over the articles published in the newspaper in March 2015.

They revealed details of a 2008 report by accountancy firm PriceWaterhouseCoopers into Ireland's banks.

The High Court heard the articles became a "source of concern" for Mr O'Brien.

He claims they portrayed him as being one of the "developer kings" who destroyed Ireland and bankrupted its banking system.

His Senior Counsel, Luán Ó Braonáin, said they portrayed Mr O'Brien as someone who had overborrowed in some disturbing way, who had received cheap and easy money from the banks, and who had been facilitated in some way by improper influence on bankers, politicians and civil servants.

He said Mr O'Brien was portrayed as someone whose identity as a substantial borrower was a secret that had to be suppressed, but was now being revealed in a daring exposé.

The court was told Mr O'Brien alleged that the articles meant that he, the politicians and the banks did not want the public to know that he was a substantial borrower from the Irish banks.

In his opening speech, Mr Ó Braonáin told the jury of eight men and four women that the Sunday Business Post was not relying on the defence of truth, but that one of the main battlegrounds between the sides would be what the articles actually meant.

He told them they would be asked to come to a decision on the issues and whether or not the case was one where an award of damages should be made to vindicate Mr O'Brien's reputation.

Mr Ó Braonáin said they would be asked to determine what sum of money would be capable of remedying the damage done to Mr O'Brien by the articles.

He gave the jurors a brief history of Mr O'Brien's life and career before taking them through some of the articles in the edition published on 15 March 2015. He said at the time the readership for the newspaper in print and online was 113,000 people.

He described how the headline on the front page described "the files they don't want you to see".

There was a picture of a dossier described as "top secret" and seven names were listed above the fold of the front page, including Mr O'Brien's.

The headline said "22 men and 26 billion" and the story described how the "secret report" by PwC showed just 22 men ended up owing €25.5 billion to their banks.

Mr Ó Braonáin said the article tied the downfall of Ireland to development and the exposure of banks to development projects.

He said the 22 borrowers were identified as being contributors to the misfortune that befell Ireland and the banking system.

He will continue his opening speech to the jury tomorrow.

Mr O'Brien is in court for the case, which is expected to last around a week.