jats:titleAbstract</jats:title> jats:pGiven the emphasis, at the time of the 2016 referendum, on the need to take back control of UK immigration policy, the article raises the question as to why the founding EU States decided not only to cede control in this sensitive field but also to allow such a generous approach to economic migration (to include not just workers but also their family members and to include equal access to benefits, including to housing) (the ‘why’ question). We also wanted to know whether any of the concerns which so resonated in the 2016 referendum campaign, especially about benefit tourism and pressure on public services, were ventilated at the time (the ‘risks’ question). Given that the contemporaneous academic literature did not offer much insight, we went to the archives and traced the evolution of the debates on economic migration in the period leading up to the signing of the Treaty of Rome, and again in the run up to the adoption of the key Regulation on workers, Regulation 1612/68 (now Regulation 492/11). We suggest that in respect of the ‘why’ question there was no single—or simple—explanation as to why the founding states agreed to the introduction of free movement but various justifications were offered. In respect of the ‘risks’ question, our research revealed little contemporaneous discussion of the concerns that subsequently took hold, primarily in the UK but also elsewhere. More striking were the extensive debates on adequate housing for migrant workers and their families. This was less couched in terms of risk but in terms of the paucity of provision of adequate housing for all families. The article concludes by considering the question as to why there was so little attention paid to the radical nature of free movement.</jats:p>