Chelsea feared being accused of a racism cover-up if they failed to report the alleged abuse of John Obi Mikel by referee Mark Clattenburg, it can be revealed today.

The club were placed under pressure when confronted by claims from Mikel and Ramires that Clattenburg had called Mikel a "monkey", and believed that some press reporters were already aware of the incident. They feared that failure to act would leave the club open to the charge that, as with the John Terry incident, they did not take racism allegations seriously

For the first time a detailed picture has emerged of what motivated the club to take the unprecedented decision to go public on the flare-up following last Sunday's Premier League game with Manchester United, and subsequently to report the matter to the FA.

The Independent on Sunday has spoken to a highly placed source at Chelsea, who admits that many of the club's actions were governed by the Terry racism storm. But we can also reveal that:

* Mikel claims to have personally heard Clattenburg call him a monkey. It was previously reported that only Ramires heard the word.

* Chelsea were mindful of FA rule E14 which says a club must report possible misconduct incidents.

* The club also took into account the 2010 Equality Act which imposes a duty of care on employers.

* Chelsea chairman Bruce Buck, who is also a lawyer, was centrally involved in all decisions.