Fritz Spiegl had an extraordinary life. He grew up in Austria. In 1939, his parents sent him, aged 13, to England to escape the Nazi persecution of the Jews. He came to Liverpool in 1948 as principal flautist of the Liverpool Philharmonic Orchestra.

He became an adopted Liverpudlian - his publications included Liverpool Street Songs and Broadside Ballads.

Johnny Todd he took a notion
For to cross the raging tide,
And he left his true love behind him
Weeping on the Liverpool side.

Johnny Todd was indeed collected in Liverpool. Fritz Spiegl and his first wife, Bridget Fry, arranged the melody as the signature tune for the BBC TV police series Z-cars. This was set in the fictional town of Newtown, based on Kirkby, Merseyside.

Sources; Mudcat and Wikipedia