Support for Celtic and Rangers isn’t based on Geography in Scotland, but about identifying with a club that represents your religious and sectarian views. It’s the same in N.Ireland. The vast majority of Catholics in Scotland support Celtic for this reason, every unionist and Catholic hater supports Rangers, but not all non Catholics do. As long as both clubs exist, this tribalism will continue, and in Britain’s divided society it is getting worse. Away fans are not now allowed to attend Old Firm games, a sad indictment on the way things are going.