Eben Black, former Sunday Times chief political correspondent, has lost his unfair dismissal case against News International, the newspaper's owners.
Black left the Sunday Times after he was offered a job as defence correspondent, which he turned down on the grounds that it was a demotion. He was sacked for gross misconduct and then took his employers to tribunal.
However, a source at the newspaper told the Media Guardian that Black had lost his job as he did not bring in enough scoops.
Black said: "The Sunday Times is desperately trying to improve its image and maybe it's because of my tabloid background that they are saying 'we don't want a tabloid journalist working for us any more'.
Black has already said he will appeal against the ruling.