Chelsea will take the strongest possible action against anyone caught chanting "Anton Ferdinand, you know what you are" during their FA Cup clash at QPR.
The Blues will ban such supporters from Stamford Bridge, even if they avoid arrest or ejection for singing the song at Loftus Road on Saturday.
Although extra police officers have been laid on for the west London derby, they have not been issued with any specific guidance on whether action should be taken over the abusive chant. QPR could instruct their stewards to eject fans caught singing the song but they have declined to comment on whether they planned to do so.
Hammersmith and Fulham police insisted anyone found breaking the law would be arrested but were uncertain whether the Ferdinand chant could be considered a breach of Sections 4 and 5 of the Public Order Act or Section 3 of the 1991 Football Offences Act, which deal with racially-aggravated offences.
The song about Ferdinand emerged in response to allegations Chelsea captain John Terry had used a racist slur against the Rangers defender during the October 23 Barclays Premier League game between the sides, something for which he was subsequently charged.
The two players are set to meet for the first time since then on Saturday, four days before Terry appears in court to protest his innocence. Just over a week after the duo's altercation, Chelsea fans were clearly heard to chant "Anton Ferdinand, you know what you are" during the club's Champions League game at Genk.
The abuse, which appears to have racial undertones, was immediately condemned by the Blues, who vowed to do everything possible to identify those responsible and act against them.
The club - who have yet to announce whether their Genk investigation has concluded - made a similar pledge after a small group of fans allegedly sung racist songs about Ferdinand on the train home from Saturday's game at Norwich.
A man was arrested on Sunday following a complaint from a member of the public, while police continued to look for other people involved in the alleged incident. They would also be obliged to investigate any complaint made if the Ferdinand chant was sung at Loftus Road but doubt has been cast on whether that would actually lead to any charges.
Criminal law specialist Haroon Shah of City law firm Christian Khan said anyone arrested over the chant could successfully argue they were calling Ferdinand a liar or a bad footballer rather than being racist.