Number 24: Follyfoot
The original novels were written by Monica (great granddaughter of Charles) Dickens and the song was performed by The Settlers, an English folk band, who got into the bottom end of the pop charts with it.
It was a challenge, drawing up this list, to pay attention to the virtues of the theme tune rather than the show. Some of my favourite shows had OK theme tunes but I had to weigh up whether my fondness for the show meant I wanted to include it. This is an example of a show I barely recall watching but I can easily remember the theme tune and could still sing along.