Sir Alex Ferguson, the Manchester United manager, has made his first contribution to the debate on the re-emergence of racism in football, suggesting four days before Patrice Evra and Luis Suarez face each other again at Old Trafford that he does believe the issue is returning to the game.

With the Football Association expecting Manchester United and Liverpool to abide by a commitment not to inflame tensions before the sides meet again on Saturday lunchtime, Ferguson said that the re-emergence of the prejudice which beset the game 20 years ago has mystified him.

"I don't understand at all where it's coming from, to be honest with you, I don't understand it at all,'' Ferguson said. "This is a moment where we have to take stock and we should do something about it if it's surfacing again, and be really hard and firm on any form or shape of racism. There have been a couple of examples recently which is not good. In 2012, you can't believe it. It was obvious maybe 20 years ago and the improvements have been for everyone to see.''

The manager's comments came on the day that two teenagers who racially abused the Newcastle United striker Sammy Ameobi on Twitter were given final warnings by police. There is evidence that social networking sites have been a vehicle for racist abuse following allegations against Suarez and Chelsea's John Terry. But Ferguson's words appear to reflect Suarez's ban for the use of the word "negro'' against United defender Evra and they will infuriate the Liverpool manager, Kenny Dalglish, who has never accepted the verdict of an FA-appointed independent regulatory commission.


Dalglish first risked re-igniting the row with United on Monday night, when he said that Suarez should never have been banned, a comment which the FA does not consider to have been helpful. Ferguson's own contribution was made at around the same time, in an interview with CNN at the Laureus World Sports awards in London on Monday evening.

Until now, his only contribution to the race debate had been his declaration on 23 December that "the [Suarez/Evra] matter is over and I think we're satisfied that the FA have found the right decision''.

But with Terry to stand trial in July to deny a charge that he racially abused Queen's Park Rangers' Anton Ferdinand, Ferguson was willing to expand. "I have had some fantastic black players, absolutely magnificent black players, and with every one of them I have enjoyed my working relationship with them,'' he said. "But this is a moment where we have to take stock. I think we should do something about it if it's surfacing again, and be really hard and firm on any form or shape of racism.''

It is a matter of debate whether the type of on-pitch racism which beset the game in the 1980s has actually returned, or whether the underlying problem is individual cases proving to be an excuse for despicable behaviour from those who watch the game. Anton Ferdinand received a bullet in the post before QPR faced Chelsea in the FA Cup last month. Fans subsequently booed Evra at Anfield and Rio Ferdinand at Stamford Bridge - simply because he had supported his brother, Anton.

The FA will not re-issue its reminder to United and Liverpool of their responsibilities not to inflame tensions ahead of Saturday's match, though the game's governing body does consider tweets from players to be a form of public communication which carry a responsibility.

Wayne Rooney's use of Twitter to say that Suarez should have been sent off for his challenge on Tottenham Hotspur's Scott Parker at Anfield on Monday night was incendiary, posted as it was three minutes after the Uruguayan's return from the eight-game ban imposed for the racial abuse of Evra.

The FA sees Rooney's message as an opinion, rather than an attempt to stoke the atmosphere before the Premier League match in which Suarez is likely to start his first game for Liverpool since his ban. It remains unclear if United, like Manchester City, will ask their players to desist from any potentially inflammatory use of Twitter this week.