During the British film gala, John Davidson, who has Tourette's syndrome, could be heard shouting the "n-word" when actors Delroy Lindo and Michael B. Jordan presented an award.
The remarks were not edited out of the subsequent television broadcast, which was shown with a two-hour delay.
The BBC's complaints department - which received a "large number of complaints" - now says this should not have been broadcast and that it was a clear breach of guidelines, although it notes that the breach was not intentional.
