Satirical gameshow Mock The Week breached guidelines over comments aired about swimmer Rebecca Adlington, the BBC Trust has ruled.
Panellist Frankie Boyle's remarks about the Olympic champion were "humiliating" and "risked offending the audience".
The show, broadcast in August 2008 in the wake of the Beijing Olympics, prompted 75 complaints from viewers.
Its producer apologised in December, saying "the ribbing may have gone a tad too far on this occasion".
The trust's Editorial Standards Committee also concluded that double gold medallist Adlington had not courted publicity or celebrity status, making the personal remarks unjustified.
They added that the makers of Mock The Week, who allowed sexual innuendo and comments about Adlington's appearance to be included, failed to have an editorial reason for including them.
The committee's decision is a final ruling on a complaints process that has been in progress since last year.
Another complaint against Mock The Week, relating to a comment made about the Queen, was not upheld as a breach of editorial standards by the trust.
The panel show also features comics Hugh Denis and Dara O'Briain in the role of chairman.
The BBC recently announced that Boyle was stepping down from the show after seven series to concentrate on other commitments.
The Scottish comedian, known for his dour, cutting humour, was called "a brilliant member of the team" by a spokesman for the programme.
Meanwhile, BBC Three's Most Annoying People of 2008 show was found by the Editorial Standards Committee to have made "crude and offensive" jokes about the lesbian relationship between actress Lindsay Lohan and DJ Sam Ronson.
Remarks made by radio host Spoony and porn actor Ron Jeremy were deemed to be "crude and offensive" and appeared to "reinforce stereotypical views", it ruled.
The committee has asked for the remarks to be removed from any repeats of the programme.