Clattenburg stood down from duty
Mark Clattenburg was stood down from refereeing for a week on Monday after the Football Association launched an investigation into allegations he used "inappropriate language" towards Chelsea stars John Obi Mikel and Juan Mata.
Clattenburg was accused by the European champions on Sunday night of making offensive comments, which are understood to have been interpreted as racist, during their acrimonious Barclays Premier League defeat to Manchester United.
Chelsea lodged a formal complaint with the match delegate, sparking an almost inevitable chain of events that on Monday afternoon saw the FA announce an investigation and Professional Game Match Officials withdraw Clattenburg from the firing line.
After deliberately omitting the 37-year-old from the games the refereeing body were due to officiate on Friday, Saturday, Sunday and Monday, PGMO said in a statement: "Professional Game Match Officials believe that, with any football match, the focus should not be on the officials but on the players and the game itself.
"Mark Clattenburg is one of the elite referees in world football and, in these circumstances, the intense level of scrutiny would detract from the match and be unfair to the clubs and the supporters of both sides."
He said: "Initially, it is insulting words and I must admit I smiled at that because we watch football matches every week of the year hearing players use insulting words to referees and then somebody takes umbrage when somebody allegedly says something back. But I just hope this can be cleared.
"It's slightly ironic that players dish it out left right and centre and then if - and there is a massive if - something has been said back - and we're not talking about racial here, we're talking about like for like - then I don't think anybody's got a right to complain.
"I'm not saying referees should do it, but there seems to be one law for one set of people and one law for another, but this inference that racial language has been used is very, very serious."
Anti-racism group Kick It Out refused to comment on the unfolding story until the investigation was complete.