This paper will specifically examine the historical impact of decolonization, integration and immigration on the 2020 Brexit decision. The research will identify key events that have contributed to a rise in British Euroscepticism which has continuously served as backdrop for British isolationism and anti-immigrant thought. A study of the increased movement of people attributed to mass mobilization following decolonization and integration will play a key role in highlighting the effects Brexit will have both on Britain and on an international platform. Emphasis will be placed on the implications this history and resulting policies will have on the economic prosperity and stability of future Britain. In this paper, the focus will largely be placed on the post-1973 period, after Britain’s entrance into the EEC. Analysis of the latter quarter of the 20th century will contribute to a better understanding of modern events, decisions and predictions