Thanks, Jim. I'd forgotten the New City Songsters when I was thinking of this.

You have sparked off a memory, though. Miles Wootton once cornered me in a folk club interval and said that he was contributing a song to New City Songsters and he was singing it to what he thought was a tune of a traditional tune. If he hummed it, could I identify it? He started humming and straight away I knew it was the tune of "Nicky Tams".