A SUFFOLK match official has emerged as a key figure in the probe into allegations against football referee Mark Clattenburg.

Chelsea reported Mr Clattenburg to the Football Association for allegedly using “inappropriate language” while refereeing their match with Manchester United on Sunday.

The European Champions made the complaint about what are understood to have been interpreted as racist remarks towards midfielders John Obi Mikel and Juan Mata.

Simon Long, formerly Suffolk FA’s referee development officer, was one of the linesmen at Stamford Bridge and it is thought he will play a crucial role in the FA’s probe.

David Porter, chairman of Suffolk FA, said a microphone attached to Mr Clattenburg would have picked up any comments he made and relayed them to both his assistants and the fourth official.

He said: “I would have thought he’ll playing an integral role - although no-one really knows what the charge is or what went on.

“He would have heard everything. The referee is on an open microphone, which the two assistants are connected to.

Mr Porter added he believed the FA’s investigation into the matter had begun yesterday.

“He’s just a witness, he’s not under any scrutiny,” he added.

Commenting on Mr Long’s time with Suffolk FA, he added: “He was a very decent referee and it was obvious to me he would go a long way in the referring fraternity.”

Mr Clattenburg, 37, has been stood down from officiating for a week.

He also been reported to the police over the matter on Sunday.

The man behind the mooted black players’ breakaway union, Peter Herbert, sent a letter to the Metropolitan Police Service (MPS), which read: “The Society of Black Lawyers wishes to record the incident that took place at Chelsea FC.

“Our information is that racist remarks were directed at John Mikel Obi and at Juan Mata. If so, that is wholly unacceptable in any circumstances.

“Although this matter may be investigated by the FA, it is appropriate that the MPS independently see if a racially-aggravated offence has occurred.”

The police confirmed they had received what they described as a “complaint” and were considering it.

A national newspaper yesterday reported Mr Clattenburg was set to deny allegations he used “inappropriate language” and that he was “shocked” and “angered” at the accusations.