During the 19th century, British trade with the rest of the world was growing rapidly. The large number of ships being wrecked each year caused greater and greater concern. For example, in the year 1873-4, 411 ships sank around the British coast, with the loss of 506 lives. Overloading and poor maintenance made some ships so dangerous that they became known as 'coffin ships'. One of the first attempts to force ships to carry loading marks for safety was made in 1835 by Lloyd's Register, a large company that insured ships. They introduced rules about loading, but these only applied to those ships registered with the Lloyd's company itself. Other ship-owners could still do as they liked when they loaded their ships. If they chose to disregard safety, no one would stop them.

Seamen worried about the dangerous condition of ships, and many refused to go to sea. In 1855, a group of seafarers calling themselves 'The seamen of Great Britain' wrote to Victoria the then Queen, complaining that courts had found them guilty of desertion when they complained about going to sea in dangerous ships. Around the same time, an inspector of prisons reported that nine out of twelve prisoners in the jails of south-west England were seamen, imprisoned for twelve weeks for refusing to sail in ships they considered to be un-seaworthy, or without enough crew. In one case in 1866, the whole crew was jailed, when they refused to set sail on an old ship.

Different attempts, like that of Lloyd's Register, were made over the years to ensure that only safe amounts of cargo were loaded, but there was still no compulsory system to force ship owners to act to protect their ships. In 1870, Samuel Plimsoll MP, who was a coal merchant, became interested in the subject. He began to write a book about the disastrous effects of overloading ships. When he began to investigate, Plimsoll found the problem was even worse than he had expected. He began to campaign in parliament with the aim of improving safety at sea. Many ordinary people became very interested in his book and his campaign. In 1872, a Royal Commission on Un-seaworthy Ships was set up to look at evidence and recommend changes. Plimsoll was defeted several times in parliament, but he continued in his fight until load lines became compulsory. He became so famous that several popular songs were written about him.

The Merchant Shipping Act of 1876 made load lines compulsory, but the position of the line was not fixed by law until 1894. In 1906, foreign ships were also required to carry a load line if they visited British ports. Since then, the line has been known in the U.K. as the Plimsoll Line. To this day, it still carries the name of the MP who fought such a long struggle in parliament to win better safety conditions for ships crews. Together with other important changes made to ships in the Victorian period, load lines helped to preserve the lives of ships crews and passengers.