The Sunday Tribune will immediately begin the process of finding a new editor after Mr Matt Cooper announced his decision to leave the job he has held for six years.
In a separate development, the newspaper has terminated the contract of its Northern Editor, Mr Ed Moloney, amid angry claims and counter-claims about his working relationship with the Tribune.
Mr Cooper told staff yesterday that while he enjoyed the editor's job immensely, he wanted to take up the presenter's position on Today FM's drive-time programme The Last Word. He will edit this Sunday's edition and then step down, although he will continue to write for the paper. He said the presenter's position was the only one he would have left the paper for.
Mr Cooper will start presenting the radio programme in the new year. The current presenter, Eamon Dunphy, is expected to stay on for another few weeks, and others will fill in during December.
One of Mr Cooper's last acts as editor was to inform Mr Moloney that his position with the newspaper was at an end. The two men differed sharply last night on the circumstances which led to the decision, and accused each other of reneging on a written agreement drawn up when Mr Moloney went to live in the US for a year.
Speaking from New York, where he recently completed his book, The Secret History of the IRA, Mr Moloney said he had been sacked. He added that he had not wanted to return to Belfast because he would now be at risk there, but had been hoping to continue working for the newspaper from Dublin.
Mr Cooper said Mr Moloney had effectively "dismissed himself" by refusing to return to his job. The company had given him "humanitarian leave" for 12 months and paid him full salary in return for a weekly column from the US, he added.
The National Union of Journalists has vowed to fight the dismissal. Its Sunday Tribune chapel has called an emergency meeting today to discuss the situation.
Mr Jim Farrelly, managing director of Tribune Newspapers, said the company was sorry to see Mr Cooper leave. "He is an extremely talented journalist. And we all wish him every success in his new career."
Mr Cooper was responsible for considerable expansion at the Sunday Tribune. The paper's average size is 88 pages, compared to about 56 six years ago. He particularly expanded coverage of sport, business and lifestyle issues.
However, the Sunday newspaper market has become extremely competitive, with the Sunday Times and Ireland on Sunday mounting serious challenges. The Sunday Tribune's circulation stands at just over 85,000. During Mr Cooper's editorship, circulation has hovered between 83,000 and 90,000. Mr Paddy Murray will edit the paper until the new editor is appointed.