Ross Noble's impression of "elephant man" John Merrick in an edition of Have I Got News For You has been ruled to be "at the margins of acceptability" by the BBC Trust.
But the Trust's editorial standards committee said the comic was making a reference to the screen portrayal of the disfigured Merrick by actor John Hurt, rather than mocking people with disabilities.
The committee said the show did not breach editorial guidelines by screening the footage.
Noble did his impersonation as he bantered with panellist Paul Merton and made a gag that actors in a fast food advert had trained at the John Merrick Academy of Drama, as he jokingly performed the famous line "I am not an animal" from the The Elephant Man in a slurred voice.
The committee did not uphold a complaint about the show, screened in June, but added that it "considered that the impersonation of John Merrick's speech and physical disability, in particular, was at the margins of acceptability".