»Evolution and Organisation of Mass Parties in the UK. Leadership Elections and the Legal Principle of Intra-party Democracy«: The British legal system has always been a curiosity to continental lawyers, in particular the (law of the) political process. Historically, British parties are free to choose their internal structure. Thus, they can be Internet-based mass membership parties or leader-centered one-member parties. This thesis explains how British party law, developed under the classical concept of liberalism, responds normatively to the legal, political, and social challenges it faces in modern society.