O'Brien, Mike, “The Edwardian tariff debate: Economic policy in British imperial and domestic politics, 1902-1914”, PhD thesis, QUEEN'S UNIVERSITY AT KINGSTON (CANADA), 1999. Brief summary.

 “Economic policy was one of the most contentious issues in British politics in the years between 1902 and 1914, with much of the debate hinging on whether Britain should give up its long-standing Free Trade policy and adopt protective tariffs. The greatest challenge to Free Trade came in May 1903, when Colonial Secretary Joseph Chamberlain called for the creation of an Imperial preferential tariff system. While Chamberlain's initial motivation appears to have been to promote the unity of the Empire, the cause of "Tariff Reform" quickly expanded to embrace a wide range of political concerns, and came to be touted as a remedy for a whole host of social and economic problems. The case for a new tariff system was not always a consistent one, though, and its proponents frequently contradicted one another….  While the Tariff Reform cause appeared at a few points to be on the verge of a breakthrough, it did not succeed in carrying the electorate. The reasons for this are explored in an analysis of the reception of the Tariff Reform argument among different groups of people in the United Kingdom, including capitalists, agriculturalists, the working class and women…. The reception of the Tariff Reform argument in the overseas Empire is next discussed, with particular attention paid to Canada and India.... (T)he economic and political situations in most of Britain's overseas possessions mitigated against the successful implementation of an Imperial tariff scheme.” From the abstract.