A new criminal investigation into racism in English football began on Tuesday when police formally opened a case into claims a referee directed ''inappropriate language'' at two Chelsea players during a match.

Referee Mark Clattenburg is accused of abusing midfielders John Obi Mikel and Juan Mata during Sunday's 3-2 loss to Manchester United in the Premier League, according to the lawyer whose complaint sparked the police investigation.

A day after the globally televised match, Society of Black Lawyers chairman Peter Herbert said he asked officers to look into whether a ''racially aggravated offense has occurred'' at Stamford Bridge.

The Metropolitan Police responded in a statement on Tuesday by announcing that ''an investigation has been launched into alleged comments made during a football match between Chelsea FC and Manchester United FC.''