E D Morel's work as a shipping clerk in Liverpool led him (in books such as Red Rubber) to expose conditions in Congo, which was in effect being run as a slave state by the Belgian king Léopold II. Josiah Wedgwood MP called this "perhaps the greatest single-handed fight that any man has ever won".
In 1914, Morel founded the Union of Democratic Control, which argued for parliamentary control of diplomacy and a fairly negotiated peace. Several newspapers, especially the Daily Express, implied that the UDC was funded by Germany and advocated breaking up their meetings with physical violence.
In 1917, Morel was jailed on a trumped-up charge under the Defence of the Realm Act. He left the Liberals (having been their nominated candidate for Birkenhead) and joined the Independent Labour Party.
He was elected Labour MP for Dundee in 1922, defeating Winston Churchill, someone he saw as "a personal force for evil".