For instance, in the version of the Lover's Ghost I've got here, a young woman is visited by the ghost of her dead lover, who is called Willy. He tells her that he can only stay until the cock crows. Alas, the cock crows three hours early, and he has to go.

Which is it? I think this is a great song, but there are lots of places where you couldn't sing it without sniggering in the back row. And if it is intentional double entendre... well fine, but it doesn't come across to me as a boisterous number, more of a melancholy and haunting one.

There seem to be a lot of Willies in folk song. Will the folk police come to take me away if I change them to Billy?