THE Football Association today launched a formal investigation into allegations County Durham referee Mark Clattenburg used inappropriate language towards John Obi Mikel and Juan Mata during Chelsea's acrimonious defeat to Manchester United.

Consett-born Clattenburg was last night accused by the European champions of making comments which are understood to have been interpreted as racist during yesterdays Barclays Premier League game at Stamford Bridge.

Chelsea made an official complaint to the match delegate, whose report today appeared to have been passed to the FA.

A statement from English football's governing body read: "The FA has begun an investigation relating to allegations made following Sunday's fixture at Stamford Bridge between Chelsea and Manchester United.

"The FA will make no further comment at this time."

Former referee Jeff Winter thinks Clattenburg will not officiate a match again if it is proven that he racially abused a Chelsea player.

Luis Suarez and John Terry received respective eight and four match suspensions this year for racially abusing Patrice Evra and Anton Ferdinand, but Winter, from Middlesbrough, who refereed for over 25 years, thinks Clattenburg will not be able to take to the field of play again if he is found guilty.

"If a match official has used racial insults or language to a player then hes for the high jump," Winter told Radio 5 Live.

"He won't be getting a four-match or an eight-match ban, it'll probably be the end of his career, but that is if indeed he did say anything."

Clattenburg was unavailable for comment directly, but the body that represents referees, Professional Game Match Officials (PGMO), has released a statement in which it said the referee has promised to co-operate with any investigation.

Winter feels there is no way that Clattenburg can continue refereeing while the allegations are hanging over him.

"I feel it very unlikely that Mark Clattenburg would be allowed to referee until it's dealt with so we certainly dont want this going on for weeks and months," Winter said.

Winter admitted that he found it ironic that this time it was a referee that has been accused of using inappropriate language given that officials are subjected to abuse from players and fans at almost every match.

Winter added: "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, if something has been said back - and we're not talking about racial here, were 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."