One of the most important post-war economic developments in Britain has been a widening of regional disparities, initially between North and South, and then between London and the rest of Britain. By the 1980s the North-South economic divide was coupled with a political divide between a poorer Labour voting North and a more prosperous Conservative voting South. By 2019 the richest region, London, was the most Labour voting. This paper develops various theories that may help explain these developments, especially regarding the social consequences of economic divergence for inter-regional migration and intra-regional inequality. Hypotheses are tested using a mixture of macro-regional and micro-individual level survey data over time. The analysis and results will be important for understanding how economic geography may affect political developments in other high-income democracies.