A Chelsea fan will face no further action after he was accused of making a racist gesture during the club's League Cup match with Manchester United in October.
The 28-year-old was arrested and banned by the Blues during the police's investigation, but after "taking witness statements from those around him and viewing CCTV" no further action will be taken.
Police say the decision not to charge was taken with the Crown Prosecution Service.
A Metropolitan Police spokesman said: "The Metropolitan Police Service (MPS) takes any allegation of racist chanting and/or behaviour very seriously and if any matters are brought to our attention they will of course be thoroughly investigated.
"The MPS routinely work very closely with football clubs and partner agencies to monitor behaviour to ensure public confidence and safety."