New Zealand-born Katherine Mansfield identified as a cosmopolite and ‘a stranger – an alien’; she staked her claim to London citizenship through writing the city, while asserting her colonial status and co-opting Maori identity. These multiple identities were playfully self-fashioned, but Mansfield was also interpolated as an outsider by the British state. Mansfield was resident in London during a period of decisive change in immigration politics and policy: from the Aliens Act of 1905 and its classification and expulsion of ‘undesirable’ alien bodies, to wartime legislation designating certain aliens as enemies, and (re)introducing passports, registers, identity books, travel permits, labour permits, and internment, to the declaration that British subject status could be lost by women who married a foreign man, to the expansion of wartime immigration controls in peacetime. This chapter considers literary representations of colonial migration and displacement in and around London, how these shifted during the Edwardian period, and then again during wartime, and how such literary representations shaped and were shaped by a broader national discourse (and discourse of nationality).