It had been uttered by Helen McDermott towards her co-host, the former Norwich City and Leicester City footballer Darren Eadie, pictured left, during the recording of a link.
The segment had never been intended to air and Helen, a former Anglia Television newsreader, publicly apologised on the channel for the language used in the take.
The clip, which was removed from any repeat showing on the channel or online by Archant, can still be seen on YouTube.
In it, Helen said: “This is what happened when this c*** went to Happisburgh beach to look at some fossils or something.”
Ofcom’s report states: “The licensee said that the broadcast was “entirely unacceptable” and it sincerely regretted the incident. It explained that the programme segment in question was pre-recorded and this version, containing inappropriate language used in jest, was included in the final edited programme in error.
“The licensee said that the presenter broadcast an apology the following evening and that the inappropriate language was removed immediately from any repeat broadcast of the programme and the version available online.
“It added that disciplinary action had been taken against the staff concerned and compliance procedures tightened to ensure the circumstances which resulted in this incident would not happen again.”
The complaint was upheld, and the full adjudication can be read here.
An Archant spokesman said: “Mustard TV has nothing further to add to its contribution made in the Ofcom adjudication.”