Manchester United manager Alex Ferguson rubbishes Chelsea's racism allegation against Mark Clattenburg

Manchester United boss Sir Alex Ferguson has hit out at Chelsea for accusing referee Mark Clattenburg of racially abusing John Obi Mikel during Sunday's fiery clash at Stamford Bridge.

The Metropolitan Police and the FA are investigating an allegation that Clattenburg used 'inappropriate language' towards Mikel during the game in which he sent off two Blues players as they went down 3-2 to Ferguson's side.

'I don’t believe Mark Clattenburg would make any comment like that,' said Ferguson.

'I think it’s unthinkable. It’s unthinkable in the modern climate. I just don’t believe it.

'There’s no way a referee would stoop that low. I’m convinced of that.

'If you look at the modern game compared to 25 years ago it’s completely changed. I know the banter between players and referees 25 years ago is completely different.

'I have never heard a player come to me in the last 15 years and say a referee has sworn at them during a game, ever.

'This is where I stand on this issue with Mark Clattenburg. I just don’t believe it.'

It is understood that Clattenburg will receive the full backing of his fellow officials during any investigations.

Assistant referees Michael McDonough and Simon Long, and fourth official Michael Jones did not hear anything untoward said on their linked headsets and are expected to say as much in any testimony.