Yes it's true there is violence at football matches in the U.K. such that when I went to my first American football match (a Raiders game at that ) I was amazed at the lack of violence and the general good nature of the crowd. At the same time I don't think you can make general comparisons from that. Most of the time they're not actually killing each other on the streets of Manchester unlike the streets of Oakland whose homocide rate for this year exceeds that for the whole of the UK. Take this from one who knows both cities.