The incident took place one evening in September 2008 when a 20-year-old black woman stepped aboard and asked the 50-year-old driver where the tram was headed, reports the Göteborgs-Posten newspaper.

The two then entered into a hostile exchange of words during which the driver called the woman “din jävla negerfitta”.

The slur prompted the woman to report the driver and he was eventually charged with agitation against an ethnic group for the remark.

The term combines the Swedish term for “nigger” with a highly offensive term referring to the female reproductive organ. The rough English translation of “Jävla” is “damn” or “fucking”.

In its ruling, the court agreed that the insult, which the driver admitted saying when questioned by police, was certainly “inappropriate” and “reprehensible”.

However, as so few people heard the offensive remark, the court found that the driver was not guilty of committing agitation against an ethnic minority, which has a prerequisite that the offensive remarks also be spread.

Because no more than two people other than the woman heard what the driver said, the court therefore ruled the driver should be acquitted of the charges.