Ralph Miliband's influential Marxist critique of Parliamentary Socialism (1961) depicted a Labour Party that had condemned itself to futility by its dogmatic commitment to parliamentary methods. By contrast, Social Democratic writers such as Ben Pimlott have argued that Labour's reformism secured concrete gains, whilst accepting the premise that the party's electoralism/parliamentarism went unquestioned at the time. Both sides are right insofar as no group within the party suggested abandoning parliamentary methods. What has been forgotten, however, is that there was considerable debate after 1918 about how Parliament should be used. Not only was Labour's commitment to Parliament challenged by other parties, which alleged extremism and disregard of the rhetorical conventions of the Commons, but Labour itself accused its opponents of riding roughshod over parliamentary liberties. Thus, the decision of some left-wing MPs to use parliamentary disruption tactics in their quest to present themselves as spokesmen of the unemployed was depicted by them as a proper use of the Commons to challenge capitalism and by Conservatives as proof of Labour's innate extremism and unfitness to govern. Issues of class were central to these understandings, and gender was also important. This article examines the arguments about Parliament and parliamentary methods that were conducted within and without the Commons, often through symbolic manifestations such as rowdy 'demonstrations' within the Chamber. It concludes that the inter-war experience taught Labour not the possibilities of Parliament but its limits.