Any attempt at comparing contemporary change in the UK and France is a bold one, since it means discussing two very different countries with strong distinctive constitutional identities. This book places its emphasis on the shared historical, political and cultural background of the UK and France, before focusing on the sweeping transformation of their constitutional frameworks in the past quarter of a century at a national and regional level – with a particular emphasis on Wales and Scotland – which culminated in the June 2016 referendum on Britain’s EU membership. Instead of examining each country separately, however, as is traditional, this study breaks new ground by explaining the pattern of institutional development in Britain and France from a comparative Franco-British perspective. It explores the complexities of recent constitutional change in both countries in an original and comprehensive way, and gives both British and French readers a deeper understanding of the two countries that have some much in common even though Brexit could drive them apart.