BBC Radio 4 has been criticised after the words "cox sackers" were broadcast during an afternoon show.
The host of the Thinking Allowed show, Laurie Taylor, read out an email which referred to the sacking of a cox from a rowing team.
A listener complained that an afternoon show contained the "grossly offensive play on words".
The incident took place at 4.15pm on April 25 last year.
The BBC Trust's Editorial Standards Committee, which upheld the complaint, concluded: "The phrase was not articulated clearly enough and could easily have been misheard for the offensive word "c*** suckers" by the majority of the audience."
It went on: "The committee was concerned that the content was broadcast at a time when a significant number of children are available to listen to the radio and are more likely to be travelling in cars where Radio 4 might be on during the school run.
The BBC initially defended the broadcast, with its editorial complaints unit claiming that "the offensive words themselves are not actually used" and "Radio 4 is essentially an adult radio channel".
But the trust ruled that it was in breach of the corporation's editorial guidelines.