The thesis reassesses the presence of French émigrés from the 1848 revolution within a British context. In particular, it investigates their role in the transfer of the wide-ranging and often contradictory wealth of revolutionary concepts and political doctrines among the small but influential coterie of Victorian radicals and journalists who welcomed them and disseminated their ideologies. The part played by the transmission of these ideas within the 'continuity thesis' regarding radicalism in Britain is thus re-examined, challenging the premise that there was a complete political hiatus between the Chartism of the 1840s and the advent of socialism at the end of the nineteenth century. The varied transnational spaces within which revolutionary ideas were exchanged, debated and promoted are explored together with the vectors through which they were transmitted to a British public by figures as diverse as G.J. Harney, Ernest Jones, John Ludlow and Charles Bradlaugh. The thesis shows how these connections stimulated a new political language inspired by different strands of French socialism, secularism, republicanism and Freemasonry, and how this exposed both divisions of class and political direction within British radicalism while paradoxically encouraging a sense of patriotism. The quarante-huitards are here firmly located between the previous French migration to Britain beginning in the 1830s and the subsequent arrival of Communard refugees in 1870- 71, as well as within the wider continental émigré community. Through biography, the backgrounds and lives of certain figures within both groups are traced including Louis Blanc and other 'chiefs' in exile, as well as members whose years in Britain, like that of Jeanne Deroin, have until now been obscured. The impact of influential figures with whom they associated such as Mazzini and Marx are also considered, during a distinct period that was witnessing the decline of Chartism and ushering in a new spirit of commercial liberalism as reflected in the Great Exhibitions of 1851 and 1862.