Between 1924 and 1933 scores of British and Irish immigrants were deported from South Africa for crimes that were mainly of a petty character. Prominent in their records was the offence of supplying alcohol to black people, which had been criminalised under the country’s racial forms of prohibition. These deportations took place under the direction of the minister of the Interior, D. F. Malan, later notorious as the initiator of the apartheid policy. The article contends that the process of deportation is revealing of both the social trajectory of some metropolitan migrants to the Empire and of the character of the South African state. While turn-of-the-century British immigrants to southern Africa are generally thought of as upwardly socially mobile, a minority took a downward path. As ‘poor whites’ they constituted a threat to racial boundaries. Malan, concerned to police these boundaries, sought to remove them from society. But he was constrained by his political alliance with the British immigrant labour movement and in the end was selective in his strategy, deporting the most marginalised or lumpen proletarian, while allowing those who could claim some shreds of respectability to remain. The organisational and bureaucratic processes of deportation are traced in detail. The article endorses Robert Bickers’ view that imperial history has given too little attention to poor and working class British immigrants in the Empire.