The BBC says an "unfortunate error" is to blame for Newcastle being called "black and white scum" in subtitles during a Premier League broadcast.
Football writer Paul Brown spotted the gaffe and tweeted a screenshot of the phrase from Sunday night's Match of the Day 2 show.
The author wrote: "MOTD2 subtitler evidently not a Newcastle fan."
Commentator Guy Mowbray was discussing Liverpool striker Daniel Sturridge's good form against Newcastle, saying he had scored five goals against the black and whites.
But subtitling software misunderstood the word "comma", which had been spoken by the subtitler, known as a "respeaker", and inserted the offensive word "scum" into the text on screen.
A BBC spokeswoman said: "Our live subtitling service is normally very accurate and makes our content much more accessible, but there are times when unfortunate errors occur. "On this occasion the error was spotted and corrected immediately."
The Premier League match between Newcastle and Liverpool ended in a 1-1 draw.