Jon calls this one “Probably the only song in the revival repertoire written in the Locrian mode. Amazingly it doesn’t sound that strange and lyrically it’s a tour de force by Kirkpatrick senior.”
John Kirkpatrick that is, who has recorded his own version, as has Martin Carthy and you can read more about those at Mainly Norfolk. I don’t have an awful lot more to add and am not scholarly enough to comment on the Locrian mode or scale, although you may like to look at this and this. I’m sure it will make more sense to the singers amongst you, but it gives a slightly odd feel to the tune, which seems to suit the matter-of-factness of it all. For some reason I’m getting a ‘musical’ film feeling from it with visions of a sinister Dick Van Dyke flickering in my mind. I’m not sure why… It may just be the peculiar sort of day I’m having.