:::::And? That article is not on about English football, it is on about one specific club, which has a notorious history. The only way you can compare it is with an article on a specific Orange lodge or district. You haven't answered my questions or have you no answer? 
 :::::Unlike anyone else here so far, here is a source for wording we could use: BBC News. It gives an overview of the history of trouble and parades and uses the words "periodically" and "sporadically". Better than sourceless opinions which seem to be the rage in this WikiProject these days.