The Brexit vote — the British people’s vote to leave the European Union in 2016 — represents the outcome of a successful populist movement. More recently, the Conservative Party’s staggering 2019 electoral success demonstrated that the populist “Get Brexit Done” message remains popular among both traditional Conservatives and broad swaths of the working class in former Labour Party strongholds. This study aims to explain the Conservative Party’s marked change rhetoric and policy, as well as factional shifts within the halls of Westminster, in response to the ongoing Brexit negotiations. While some scholars look at the supplyside causes of populism (elites and political parties) and others look at the demandside causes (the voters), this study applies a third school of thought that examines the relationship between supply and demand by analyzing a series of interviews with Conservative Party staff as well as public opinion polling. In doing so, the study concludes that there has been a deep, reciprocal, and simultaneous onset of populist Euroscepticism within both the Conservative Party and the working class that has structurally re-aligned the Conservative Party for decades to come, from more ‘libertarian’ to more ‘authoritarian’ in nature. A feedback loop between the new Conservative base and the Conservative Party has rendered and reciprocated a new mentality among voters. This research contributes to the existing literature as an example of the aftermath of populist movements when both elites and voters are able to forge cooperative relationships to achieve their goals.