Jon names his source for this as Mike Harding saying, “Fay’s started performing this which is much more appropriate, but I still enjoy singing it. Keep meaning to look at the original ‘apple tree’ lyrics in case they’re worth learning.” It’s of course based on the chorus of the popular song originally published in 1905, In The Shade Of The Old Apple Tree. It seems that this wry social commentary was just one of several adaptations and this has something of the music hall or end-of-the pier about it, although it was written in America by Harry Williams and Egbert Van Alstyne and you can read more here on Wiki. Quite when it made this transition I can’t say, but it smacks of that early Edwardian industrial grime. Perhaps Mike might tell us where he got it from.