ITV News has just reported that the slur was "I slept with your mother last night" Zindane then walked away at which point Matterazzi then said "Your mother is an Algerian whore" this is when Zidane turned and headbutted him. What upset Zidane was that his mother was taken into hospital yesterday and he was extremely worried about her. This was on the ITV News program at 10:30pm but I can't find an oline reference.