The best quick source for information on the Ice Cream wars in Glasgow is Wikipedia

http://en.wikipedia.org/wiki/Glasgow_Ice_Cream_Wars

There was a lot of speculation at the time that the ice cream vendors were pushing drugs. Why else would there have been so much violence. However this theory was never proven and crime reporters were never convinced of the idea. Nevertheless, something sparked the aggressive behaviour and Jammy Dodgers explores some provocative notions of how various aspects of city life combined to set the housing estates aflame with violence.