Honestly, I'm not sure. We're going back at least 60 years here for both clubs. It has a stronger association with us and obviously we sing the original lyrics so our claim to it is pretty strong. What's more important is how well you sing it.
I like the slow version, it creates an almost cathedral like atmosphere that fits in well with the whole 'Saints' image but I definitely prefer the fast version which we've become pretty **** at. Once we move onto the higher tempo version, everyone claps at 200bpm and the song gets lost.
I'd also like to point out how embarrassing it is when we shout "we sing our own songs" given that we don't. Perhaps, "you got the words wrong" would be more suitable?