When the Communist Party of Canada was banned in 1941, it refounded itself as the Labour-Progressive Party. The LPP only ever elected one Member of Parliament under its own banner, Fred Rose, who was elected in a 1943 by-election in Montreal and sat in the House of Commons. In 1947, he was charged and convicted for spying for the Soviet Union, and was expelled from the House of Commons.
Dorise Nielson was elected to the House of Commons in the 1940 federal election from Saskatchewan as a "Progressive Unity" MP, but was defeated in the 1945 election when she ran for re-election as an LPP candidate.
The LPP had a youth wing, the National Federation of Labour Youth which had formerly been known as the Young Communist League.
The Labourparty was founded in 1900 after several generations of preparatory trade union politics made possible by the Reform Bills of 1867 and 1884, which enfranchised urban workers.
In 1918, Labour withdrew completely from the coalition, and in 1922 it became the second largest party in the House of Commons and thus the official opposition.
The reversal of the partys position on Britains entry into the European Community (now the European Union), after having earlier supported it, and a renewed call for further nationalization of industry were indications of a greater left-wing militancy within the party.