Dissent and Rebellion in the House of Commons: A Social Network Analysis of Brexit-Related Divisions in the 57th Parliament Carla Intal1 and Taha Yasseri1;2;3;4∗ 1Oxford Internet Institute, University of Oxford, Oxford, UK 2School of Sociology, University College Dublin, Dublin, Ireland 3Geary Institute for Public Policy, University College Dublin, Dublin, Ireland 4Alan Turing Institute, London, UK May 28, 2021 Abstract The British party system is known for its discipline and cohesion, but it remains wedged on one issue: European integration. We offer a methodology using social network analysis that considers the indi- vidual interactions of MPs in the voting process. Using public Par- liamentary records, we scraped votes of individual MPs in the 57th parliament (June 2017 to April 2019), computed pairwise similarity scores and calculated rebellion metrics based on eigenvector centrali- ties. Comparing the networks of Brexit- and non-Brexit divisions, our methodology was able to detect a significant difference in eurosceptic behaviour for the former, and using a rebellion metric we predicted how MPs would vote in a forthcoming Brexit deal with over 90% ac- arXiv:1908.08859v3 [physics.soc-ph] 27 May 2021 curacy. Keywords| Social Network Analysis, Party Politics, House of Commons, Brexit, EU-Membership, Euroscepticism ∗Corresponding author. Email:
[email protected] 1 Background The British party system is widely known to be a strong and disciplined one. Throughout its contemporary history, its two main parties|Labour and Conser- vative|has lent credibility to the Parliamentary process, setting the landscape for the effective implementation of policies in the British government. It is notable, however, that the cohesion and unity in the modern British party system is persistently wedged by one issue, which is that of European integration.