In May 2004, the UK Government granted workers from the new EU member states in Central and Eastern Europe ("A8 countries") free access to the British labour market. This paper discusses the rationale and migration policy context of this decision and reviews the scale and economic impacts of the subsequent inflow of East European migrants. Free access for A8 workers was part of the Government's Managed Migration policy, designed to expand migration to fill vacancies in skilled and especially in low-waged occupations where employers found it difficult to legally employ migrants before EU enlargement. The much larger-than-expected increase in the employment of A8 workers since May 2004 has contributed to economic growth and benefited individual employers in the UK . It has, however, also raised new and still relatively under-researched questions about the distributional impacts and potential social costs of large-scale immigration. I argue that without a stronger commitment to the enforcement of labour laws and regulations, the immigration and employment of Central and East European workers in the UK is in danger of becoming an example of the kind of 'unmanaged' migration that the Government is so keen to avoid.