Premiership ref Alan Wiley has considered quitting over criticism from Manchester United boss Sir Alex Ferguson.
The Daily Mail says friends of the referee revealed that he was tempted to walk away from football over the Manchester United manager's astonishing attack.
Alan Leighton, national secretary of professionals' union Prospect, who represent referees, said: "Sir Alex made comments about other referees and said about European referees being as fit as butchers' dogs.
"But all of our referees pass stringent fitness tests at the start of the season. If Alan Wiley or any other referee were not fit they would not be refereeing."