The Onedin Line is a BBC television drama series which ran from 1971 to 1980. The series was created by Cyril Abraham. The series is set in Liverpool from 1860 to 1886 and deals with the rise of a shipping line, the Onedin Line, named after its owner James Onedin. Around this central theme are the lives of his family, most notably his brother and partner, shop owner Robert, and his sister Elizabeth, giving insight into the lifestyle and customs at the time, not only at sea, but also ashore. The series also illustrates some of the changes in business and shipping, such as from wooden to steel ships and from sailing ships to steam ships. It shows the role that ships played in affairs like international politics, uprisings and the slave trade.

Michael Marler, a successful business man in London, is about to make his way to the top. The death of his father brings him – after 37 years – back to his hometown Liverpool, where he is confronted with his lost Irish roots. He finds out that his father died because of a fight with some anglo-saxon teddy boys. It becomes "a matter of honour" for him, to take his revenge without involving the British police