"When The Boat Comes In" (or "Dance Ti Thy Daddy") is a traditional English folk song, originating in North East England. An early source for the lyrics,Joseph Robson's "Songs of the bards of the Tyne", published 1849, can be found on the FARNE archive[1]; in FARNE's notes to the song, it is stated that these lyrics were written by William Watson around 1826.
It was popularised as the theme tune to the 1970s BBC drama serial When The Boat Comes In in an arrangement by the composer David Fanshawe.
Here is verse one.
'Come here, my little Jacky
Now I've smoked my backey
Let's have a bit crackey
Till the boat comes in
Dance to thy daddy, sing to thy mammy,
Dance to thy daddy, to thy mammy sing;
Thou shalt have a fishy on a little dishy,
Thou shalt have a fishy when the boat comes in'