The referees' union claim they had to fight back against Manchester United boss Sir Alex Ferguson to make a point.

After Ferguson recently criticised referee Alan Wiley for being 'unfit', the referees' union, Prospect, asked for the Red Devils manager to apologise as to make a stand against further abuse towards officials.

"If we had not challenged Alex Ferguson over his comments, it would have lowered the bar even more in terms of the criticism and abuse referees face," said Prospect secretary Alan Leighton.

"We couldn't allow that to happen and what has happened over the last week or so has started to redress the balance."

Leighton hoped that this latest case made people more aware of the arduous task match referees face each week.

"A referee can have a good game, then make one decision a manager, players or fans disagree with and it all goes off like Krakatoa!" he added. "It's as if the referee has just committed a murder.

"When you get on a bus there's a sign at the front which says threatening, violent or abusive behaviour towards the driver will not be tolerated.

"I'm not saying we should ban or eject everyone who has a go at the referee, but there has to be a line drawn in the sand."