English Premier League:Debate has raged loud over the silence planned to commemorate the dead of Munich but Sven-Goran Eriksson made one final appeal for respect from Manchester City supporters yesterday when he urged: "Do not be a fan for that minute."

Manchester Utd v Manchester City Venue: Old Trafford Kick-off: Tomorrow, 1.30pm On TV: Sky Sports 1

Months of negotiation between the Manchester clubs over how best to mark the 50th anniversary of the tragedy will be put to the fiercest scrutiny shortly before 1.30pm at Old Trafford tomorrow when United and City hold a minute's silence for the 23 who lost their lives in Bavaria. It will be a powder-keg moment, one that Eriksson and many at City have attempted to diffuse by writing to all who bought tickets for the away section asking for their co-operation. The City manager has now asked for tribalism to be put briefly aside, even in the volatile atmosphere of a Manchester derby.

"As a club and as a manager we have sent out many messages asking people not to ruin it and to use common sense," said Eriksson. "Football is one thing, but when people die too early in an extremely bad accident then it doesn't matter if you wear a red or a blue shirt.

"This has nothing to do with football. This is about remembering people who do the same job as we do today. Everyone should have their own thoughts about what happened during that minute and I would ask them, do not be a fan for that minute."

Eriksson believes a spoilt silence, as occurred at Wembley on Wednesday, would merely aid United's motivation to deny City their first victory at Old Trafford since Denis Law's back-heel in 1974.

"I can see many factors that will motivate United," the Swede said. "The memory of 50 years ago, the points they lost at Tottenham last weekend and also that we beat them earlier in the season."

For once Alex Ferguson is in absolute agreement with his City counterpart, admitting the emotion of the occasion will have an impact on his players.

"I think the two go hand-in-hand given the history of the Munich disaster and the way that team played," the United manager said. "They (the Busby Babes) had a number of young and exciting players. Equally we have young and exciting players trying to entertain and excite.

"My team-talk won't be the same as Sir Matt's and Jimmy Murphy's, not with the sports science we have these days, but like them I will ask my players to go out and play." Ferguson added: "I hope the anniversary does provide motivation. There is always an expectation around us to do well, but I think that will be higher on Sunday."

The Scot says that United have done everything within their power to limit the prospect of trouble tomorrow, even to the extent of closing the gates to Old Trafford five minutes before kick-off. "Sometimes people arriving late to a game and singing as they arrive can disrupt a minute's silence and so we will closing the gates before kick off and re-opening them one minute afterwards," he explained. "It is right to have the silence. This is a poignant event for the whole of English football. Manchester United took English football into Europe and unfortunately lost a lot of players by doing that."

Paul Scholes has expressed strong concerns that City's supporters will attempt to sabotage the minute's silence. "The only thing I'm worried about is the minority of City fans who might want to cause trouble," the Manchester United midfielder said."It would reflect badly on their club but that's not stopped them in the past, has it?"

The sense of unease at Old Trafford has been exacerbated by reports of an increase in the number of offensive Munich chants at City's recent away matches. On Wednesday a tribute before England's game against Switzerland was disrupted by shouts from the crowd and Scholes has had enough experience of the enmity between United and City to fear there might be a repeat. "Unfortunately there is always that few who might cause problems," he said. "They have sung songs that refer to the accident a few times in the past. I just hope they come to their senses on the day."

Several blue and white scarves and messages from City supporters have been left outside Old Trafford among the many cards, bouquets and other tributes to mark the 50th anniversary of the disaster. The clubs have been trying to promote a message of unity and the away end will be decorated with posters of Frank Swift, the former City goalkeeper who was among the dead in Munich, working as a football reporter for the News of the World. "They lost someone in the accident as well, so I hope that might persuade their fans not to be disrespectful," said Scholes.

The former England international admitted that he would rather United had different opponents. "It's unbelievable that it happens to be City we are playing," he said.

• Guardian Service