Since the UK referendum on EU membership in June 2016, discussions have intensified on the UK’s relationship with the EU, with free movement of persons and immigration being two topics at or near the top of the agenda. According to polling, much of the UK electorate was concerned about the essentially unrestricted nature of EU immigration to the UK. However, the importance to the UK of retaining some level of access to the Single Market for goods and services has also been highlighted. In this context, several EU officials and leaders of other EU countries have asserted that the UK cannot be part of the Single Market without also accepting free movement of persons. This client publication explores the concept of free movement of persons and acquired rights under EU and European Economic Area (EEA) law.