Although the club did not involve the police, the Society of Black Lawyers (SBL) made a complaint to the Metropolitan Police based on media reports of the alleged incident.

Scotland Yard announced last night no action would be taken “because no victims had come forward” – and that has prompted criticism of Chelsea and the FA by SBL chair Peter Herbert for not going to the police.

Herbert said in a statement: “It would appear that there is a cosy little agreement between Chelsea FC and the FA not to report these matters to the Metropolitan Police but to have them dealt with solely by the FA.

“The FA have a dreadful record of indifference on hate crime generally; failing to challenge anti-Semitism at Tottenham Hotspur and at other grounds; eventually finding John Terry made a racist remark but remarkably found him not to be a ”racist“; whilst the derisory penalty of a four or eight match ban [Luis Suarez] is believed to be a suitable punishment for what in any other industry would be summary dismissal for gross misconduct.”

The FA is expected to announce the outcome of its investigation into Chelsea’s complaint within 48 hours.

Scotland Yard said an investigation was launched into alleged comments made during a match between Chelsea and Manchester United at Stamford Bridge on October 28.

Police said in a statement: “Inquiries were made and no victims have come forward.

“The matter will remain as a recorded incident.

“Without a victim and/or any evidence that any offence has been committed, the matter cannot currently be investigated.

“If the situation changes and a victim and/or evidence to support an allegation of a crime comes to police attention, then further inquiries will, if appropriate, be made.”

Clattenburg, 37, returned to training with the top-flight Select Group of referees last weekend for the first time since Chelsea’s complaint to the FA.