A HUGE security operation is gearing up to prevent trouble between Manchester United and Roma fans at Old Trafford tomorrow night.

More than 3,000 Roma supporters are expected in Manchester for the second leg of the Champions League quarter-final.

Despite the first leg passing off peacefully in Rome last week, there are fears of a repeat of the trouble during previous clashes between the clubs.

Some fans have vowed to exact revenge on Roma supporters for the way United supporters were treated during games in Italy.

Police have promised a high profile presence around the ground and in the city centre.

Pub licensees have been asked to be on their guard by bringing in extra security and only serving alcohol in plastic pint pots.

Supt John Graves said: "There is always a potential for some United supporters to carry on the rivalry between Roma and Manchester. It's our job to disrupt that for the majority of well-behaved fans. Yes, there are some fans with a long-term grudge, but the last game suggested it was a thing of the past.

Troublemakers

"We will certainly be setting our stall out to stop any potential troublemakers. If they are genuine fans, they will understand that their conduct could have an impact on the future success of the club.

"The fixtures between Roma and United are closely monitored by UEFA. They paid very close attention to the tie last week in Rome and if there's any disorder they will be looking at it as to whether it's something for them to be concerned about."

UEFA had threatened to move the 2009 Champions League final from Rome if last week's first leg had been marred by trouble.

Phil Burke, for the Manchester Pub and Club Network, which represents 650 licensed premises in the city, pleaded with both sets of fans to behave.

He said: "We want people to come into the city and go away saying `wow, Manchester is a great a vibrant place'.

"We are always worried when we have such a big, high profile game. We are drawing fans from all over the place and abroad.

"We want to create a family, fun atmosphere. A lot of venues will be showing the football for fans that are not able to get tickets into the stadium. We want both sets of fans to show that they can get on."