In 2016, Britain voted in a referendum to leave the European Union. After years of negotiations led by the Conservative government, this became effective in January 2020. The relatively haphazard and ideologically motivated departure from one of the world’s largest political and economic unions has undoubtedly had a significant effect on Britain’s economy, society, and politics. For instance, recent modelling by Bloom, et al. (2025) suggests that Brexit reduced Britain’s GDP by 6-8%, investment by 12-18%, employment by 3-4%, and productivity by 3-4%.[18]

While these effects are undoubtedly significant, this Index demonstrates that many underlying economic and social trends were in decline or stagnating well before 2020. While Brexit may have accelerated or exacerbated some of these trends, in most cases it was not the original cause.