The United Kingdom of Great Britain and Ireland comprised four nations and around 41.5 million people in 1900, of whom 72 per cent lived in England. In Britain, an established two-party system operated and after the extensions of the vote in 1867 and 1884 enfranchised men (about 60 per cent of men of voting age) could choose between the Liberal and Conservative parties. Most of the craft trade unions looked to the Liberal Party for social improvements and elements of liberalism had reached deep into the organized working class. But a working-class Conservative vote was also established. The parliamentary system enjoyed a wide popular legitimacy, as did the constitutional monarchy and an empire which even the left could justify (in terms of trusteeship). Prosperity was thought to depend on free trade even though Britain was the only major industrial country that took this view. At home Parliament enacted meaningful reforms often enough to give reformers belief and encouragement.