The song has been hijacked and became a favourite with IRA prisoners in the H-Blocks, and subsequently with a section of Celtic fans.
Indeed, the former commanding officer of the PIRA prisoners in the Maze prison Brendan “Bik” McFarlane performs a version of it with the band he formed upon his release.
http://www.youtube.com/watch?v=kt-xfuUroK8
It is also popular with other republican bands.
McFarlane is himself a sectarian mass-murderer - he was jailed for life for a bomb attack on a Protestant bar, survivors escaping the bar were then fired upon, as the murderers escaped they then machne-gunned a taxi rank composed of women and children. Five people died (three men and two women).
It’s almost beyond belief that Celtic FC would allow this.