This study examines the alternation between non-standard preterite come and its standard counterpart came in London English. A major component of the investigation centers on the comparison of come/came variation in the speech of Anglo (British-heritage) and non-Anglo (migrant-heritage) youth. Rates of preterite come vary markedly across different age cohorts and minority ethnic groups, foregrounding the importance of social factors as key determinants of variant use. By contrast, the internal conditioning of variant selection is not robust, as inferred from the paucity of significant linguistic effects. Similarities in variable patterning in elderly and adolescent Anglo speaker groups nevertheless suggest that shared structural affinities may be due to historical transmission. Conversely, comparison of Anglo and non-Anglo adolescents’ use of come/came variation reveals fewer correspondences in the grammar underlying variable use. The results demonstrate that data from non-Anglo groups contribute to a fuller understanding of come/came variation in an ethnically diverse metropolis.