The United Kingdom’s immigration and integration system is on the cusp of radical change. The complex patterns of mobility and settlement which had characterised the British migration system for over six decades had begun shifting at the turn of the millennium and within a decade the country’s migration landscape changed dramatically. This change was one of the principal factors contributing to the outcome of the 2016 Referendum on European Union membership, which has triggered an ongoing ‘Brexit’ transition period with yet unsettled legal and political outcomes, but which nevertheless is already affecting the UK’s demography and policy landscape. This brief magazine article summarises the main changes undergone in the UK's migration system since the second half of the twentieth century. Publishd in Turkish.