Vincent Browne, the celebrated journalist and broadcaster, has been threatened with legal proceedings against him personally by billionaire businessman Denis O'Brien.
Mr O'Brien is believed to have written to the journalist on foot of an article that Mr Browne wrote for the Irish Times about the businessman and the Moriarty tribunal.
The article complained of was written when the Broadcasting Authority of Ireland was considering the implications of Mr O'Brien's acquisition of substantial shares in Independent News & Media (INM).
Mr O'Brien, it is understood, threatened Mr Browne that he would sue him in a personal capacity if he repeated what he believed were defamatory statements about him in a published article.
Mr O'Brien is understood to have communicated directly with Mr Browne, rather than through his lawyers.
Taking legal action directly against a journalist is unusual.
Litigants would normally sue the publication.
Suing the individual journalist is a tactic usually designed to instil a fear of financial ruin into the writer of the allegedly offending article, especially when the potential litigant is somebody of Mr O'Brien's means.
Mr O'Brien previously made a similar threat against the well-known INM journalist and broadcaster Sam Smyth, but did not follow through. Michael Lowry did sue Mr Smyth in a personal capacity, but this action was unsuccessful. Since receipt of Mr O'Brien's letter, Mr Browne has written again on the subject of Mr O'Brien and his media interests.
Contacted by the Sunday Independent yesterday, Mr Browne said he did not wish to comment. And a spokesman for Mr O'Brien yesterday made no comment.