Manchester United fans have been told to avoid wearing club colours for Feyenoord trip

Football matches seldom require dress codes but the potential for crowd trouble on Thursday night has prompted an advisory letter from Manchester United to the club's supporters.

Fans travelling to Rotterdam for United's Europa League opener with Feyenoord have been warned against overdoing it with club colours given the past trouble with Dutch football hooligans. Manchester Evening News broke the story which claims that United sent a letter to the 1,400 who will be rooting for the Red Devils at the De Kuip Stadium. “For your own safety it is advisable to maintain a low profile and avoid areas of potential conflict and by dressing conservatively," the letter reads. Fans have been advised against wearing United jerseys or club scarves due to the possibility that it would provoke an attack from troublemakers in the Netherlands. It adds: “Once the game has ended, and Manchester United supporters are all out of the stadium, a special 1,200 seat train service will be provided from the stadium rail station. The service will stop at both Rotterdam and Amsterdam train stations. “Please ensure that you carry your passport at all times, as required by law in the Netherlands. There is currently a general high threat level from terrorism in Europe and you should ensure that you are mindful of your own personal safety and security whilst travelling.” Feyenoord supporters threw stones at a coach carrying United fans when the sides met in the Champions League in 1997 and tried to lure them into a bar brawl that was intercepted by Dutch police. And United just want their supporters to get in and out of the stadium without trouble, closing the letter with the following. “Finally, we hope that you enjoy your visit to the Netherlands and thank you for your support." Read more from SportsJOE: