Businessman Denis O’Brien has accused a public relations firm involving some former executives of Independent News & Media (INM) of being engaged in a conspiracy to damage him.

Mr O’Brien told the High Court he asked a private investigator to look into what he said he believed was a concerted campaign against him.

He said he had last Friday been anonymously given a dossier containing what he said was defamatory material about him.

He alleges a forensic examination of the dossier by a specialist IT company traced it to Dublin-based Red Flag Consulting Ltd, whose executives include Gavin O’Reilly, former chief executive of INM, and Karl Brophy, a former senior executive with INM.

Mr O’Brien believes a client of Red Flag Consulting is behind the alleged conspiracy and wants to be able to identify any such client. He also believes the dossier was designed to be given to people who can avail of parliamentary privilege, the court heard.

Mr O’Brien is claiming damages for alleged defamation and conspiracy and on Tuesday his lawyers obtained an interim High Court order preventing Red Flag Consulting interfering with or removing computer material and other IT items from its offices.

Mr O’Brien’s barrister, Michael Cush SC, said the material was in a dossier including eight Microsoft Office documents on a memory stick.

The material was clearly defamatory and dealt with matters including Mr O’Brien’s involvement with the Moriarty tribunal, his tax status as a resident in Portugal, the recent initial public offering of shares in his Digicel company and other allegations, Mr Cush said.

Mr Cush said Karl Brophy was a former journalist with the Irish Mirror who wrote an article in 1998 which ultimately led to Mr O’Brien receiving €750,000 damages.

Mr Brophy later joined INM and subsequently blamed Mr O’Brien for his departure from that company, he said.

‘Prior history’

There was “a very public prior history” between Gavin O’Reilly and the plaintiff, Mr Cush added.

Mr O’Reilly’s departure from INM was widely said to coincide with Mr O’Brien taking a very significant shareholding in that company.

All the defendants except Mr O’Reilly were represented by Michael Collins SC, who said he needed time to prepare his case. Mr Justice Colm Mac Eochaidh returned the matter for mention tomorrow.