A manager, against whom Mr Davies had an unresolved grievance, conducted the investigation into Mr Davies’ comments, the tribunal was told.
The judge wrote that Oscar Mayer’s disciplinary case was based on its perception that Mr Davies may have perceived that the auditor looked “typically Irish”.
Mr Davies’ phrase was found by his employer to amount to harassment, but neither his clean disciplinary record or 27 years of employment for the firm were taken into account, the judge found.
The tribunal ruled that the chosen investigator was not “appropriate”, witness statements were inconsistent and the probe was “largely based on assumptions”.
The judge said: “The claimant was accused of using an employment-ending, reputation damaging, loss-inducing, racially motivated slur, a slur which could have created an intimidating, hostile, degrading, humiliating or offensive working environment. These are serious matters,” he said.
“On the facts peculiar to this case, I found that the dismissal was unfair, which does not mean that I approve the use of the greeting in question or the use of mock accents.”