Bibliografía: p. 26

The withdrawal of the United Kingdom from the European Union has fundamentally changed the architecture of the UK’s immigration regime. Throughout its membership of the Union, the UK maintained a two-tier system of immigration under which only highly skilled workers from outside the EU were admitted to the UK, while workers of all skill levels were free to enter from the Member States of the EU. The latter enjoyed free movement rights under the EU Treaties, a cornerstone of the single market. Subject to certain restrictions, the EU free movement regime applied to those who were economically active (workers, the self-employed and services providers) and to the semi-economically active, such as students and retirees, provided they had comprehensive sickness insurance and sufficient resources. Since the 2016 referendum, the British government consistently maintained a pledge to end free movement of persons between the Union and the UK and introduce a controlled migration regime post-Brexit.