This song appears on Christy Moore's "The Iron Behind the Velvet" album from (I thiink) 1978.

From memory Christy says in the sleeve notes that he adapted the tune of "The Night before Larry was Stretched" to these words. He doesn't attribute the words which made me think that Christy had composed them, although as I recall at the time Christy had not shown a huge amount of original song-writing talent. He has tended to include more self-penned material on his subsequent albums.

I'd be interested if there's any evidence for the attribution to William Maginn (and I realise it's a long time since this was posted) or if anyone knows for certain who wrote the words.