This seminar will discuss themes in Professor Lobban’s recent book, Imperial Incarceration. At a time when commentators at home argued that the notion of the rule of law stood at the heart of British constitutional culture, in her expanding African empire Britain routinely resorted to detention of political leaders without trial. In contrast to the approach taken in India where general legislation provided for detention without trial and martial law, in Africa leaders were detained either under specific laws to justify individual detentions (often ex post facto), or under martial law declared as a matter of executive power. In doing so, officials remained aware of the need to justify detentions under law – to avoid detainees being freed by the courts – and this generated much debate, both within administrative circles in London and between the metropolis and periphery, over the nature of the rule of law.