The Metropolitan Police has confirmed it is investigating alleged racist behaviour by a home supporter during the Chelsea-Manchester United game at Stamford Bridge last night.
A photograph published in the national press appeared to show a fan making a 'monkey' gesture during the Blues' Capital One Cup fourth-round win.
Officials at Chelsea earlier confirmed the club has launched its own investigation into the incident.
More top news
MI5 face mounting pressure over claims the IS executioner 'Jihadi John', named yesterday as a London graduate, was known to them
Labour leader Ed Miliband is due to set out his party's plans on how it would cut tuition fees.
New drug driving laws are to come into effect next week, including laws on some prescribed medications.