Martin Carthy commented in the original album's sleeve notes:
The Sleepwalker is Lady MacBeth as played by the extraordinarily powerful Irish actress Sinead Cusack. She s a clever woman and I was lucky enough twice to see her performance with Jonathan Pryce as MacBeth, and this is for her. It started out as a march, but 'it' had other ideas and, in consequence, the first part has echoes of a Kerry polka whose name I can't remember. The rest is as independent as it can be (!).