Ian Huntley's Knob
A joke posted in the Naafi by Chickenpunk that was so despicable and corrosive that even now it can only be told to an audience in full NBC kit with respirators on. In the aftermath of its first operational use, apparently hardcore Naafi Beasts wet their girlie pants in an outpouring of shock and rage.
The joke was:
What's pink and smells of holly? Ian Huntley's cock.
See also Kenneth Bigley jokes.