Although the United Kingdom is usually regarded as a unitary state in the mould of the Westminster model, in reality, complete political integration and administrative standardization have never existed. Recent political devolution consolidates an increasingly diverse and asymmetrical pattern of territorial governance. Frequently, however, notwithstanding some notable exceptions, this differentiation within the UK's governmental arrangements is overlooked in much of the literature. To help correct this oversight, this article reports on the longstanding differences in the public administration arrangements of one of the UK's smaller component countries, Northern Ireland. Specifically, the article focuses on the role of the Northern Ireland Civil Service and charts some of the key characteristics and trends that have emerged under both the period of Direct Rule from London (since the end of the Stormont devolution in 1972) and in the newly-restored devolved settlement that was introduced in 1999, following the Belfast (Good Friday) Agreement.