According to Mudcats, the tune is “Sound the Pibroch Loud and High” aka 'Rise and Follow Charlie !" popular amongst several Irish bands of the period, but referencing The Corries in particular.
This being a Victorian jacobite song — which they say was used by the unspeakable Charlie Haughey during an election campaign.
A loose translation of M. Sardou’s lyrics, which in English seem…muddled, is here. Never having heard of M. Sardou, I’ll presume he is a very distant relative of the dramatist.
Any jacobite is going to have very mixed feelings about every damn thing mentioned here: in particular the Corries being a kind of soft band to sing a rousing invocation.
[ I’ve also discovered that my school assembly memories of “Rise Up, Rise Up for Jesus, Ye Soldiers of the Cross !” is really: “Stand Up, Stand Up for Jesus”.
Memory is the last betrayer.