Mark Clattenburg will not face police action for his alleged use of racist language towards the Chelsea midfielder Mikel John Obi last month. The Metropolitan Police announced that it had dropped its investigation after no victim came forward.

The Football Association said that the Met's decision had no bearing on its own inquiry, which it launched in the wake of the allegation that Clattenburg, the referee, had called Mikel "a monkey" during Chelsea's home defeat by Manchester United on 28 October. The referee is understood to have strenuously denied the allegations.

The FA's investigation continues and it hopes to be in a position either to bring a charge or to drop the matter by the end of the week. "We are still completing our investigation," a spokesman said. Chelsea had demanded that the FA takes action after instigating an internal review into the affair, which was helped by external legal counsel.

The Met opened its investigation after it received a third party complaint from the Society of Black Lawyers, which wrote to ask them to "see if a racially-aggravated offence has occurred". The Met started to investigate on 30 October and, having stated that it would liaise with Chelsea and the FA, it conducted a number of interviews, notably with Clattenburg and Mikel.

At no point, though, over the past two weeks has anybody from Chelsea or the FA made an official complaint to support the allegation of a crime and, as such, it said that its investigation had come to a natural conclusion. Clattenburg, who will not take charge of a match this weekend for the third week in succession, has strongly denied the accusation.

"Inquires were made and no victims have come forward," the Met said in a statement. "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."

The announcement by the police came on a day when Chelsea's chairman, Bruce Buck, had claimed the club were not hypocrites for supporting their captain, John Terry, in the wake of racism allegations while also lodging a complaint against Clattenburg.

Buck said Chelsea had a "duty of care" to Terry even if he has done something wrong – the Football Association banned him for four matches for racially abusing QPR's Anton Ferdinand – and that the club would have been "crucified" had they not reported the allegation that Clattenburg used inappropriate language interpreted as racist towards Mikel.

"Suppose we had tried to sweep this under the rug and said to the various players: 'Look, it's not a big deal and the press are going to be all over us. Maybe you want to reconsider.' If that had leaked out, we would've really been crucified," he told the Evening Standard.

"The press seem to juxtapose 'our support' of John Terry and what's going on here and looking at us as being a bit hypocritical. We have to divorce the John Terry situation from this. From our perspective the latest situation was pretty straightforward. We have an obligation to report what may be misconduct. We did that, in good faith and not maliciously."