Non-payment of the poll tax amounted to the largest campaign of civil disobedience in postwar Britain. Despite this, there has been scant academic investigation of either the basis or organisation of protest. This thesis attempts an original contribution to . knowledge by exploring the role of anti-poll tax organisations in promoting dissent against the charge. . Specifically, the piece examines the applicability and inadequacy of existing theories of pressure groups and social movements in accounting for the development and organisational tendencies of such groups. Using a case study approach based in three localities, the thesis examines the size, structure . and motivations of the anti-poll tax movement. Beginning with an examination of the poll tax itself, the thesis explores how weaknesses in the recovery legislation provided a valuable resource for a campaign of opposition based upon a fusion of economic circumstance and moralism. In assessing the nature of 'outsider' movement politics, the failure of parliamentary opposition to the charge and the subsequent refusal of opposition political parties to countenance non-payment are explored. The thesis argues that the anti-poll tax movement highlighted the growing redundancy of distinctions between pressure groups and social movements. Modem protest groups are frequently based upon informal networks with loose membership, based around collective action: - Within the anti-poll tax movement, the thesis highlights important differences between a largely class-based, sustained Scottish movement and a more transient, diverse campaign elsewhere. However, commonalities existed throughout the movement, based around a rejection of central control and a favouring of decentralised, localised opposition.