This article examines arms-length 'regulation' of UK government – the public-sector analogy to regulation of business firms — and assesses the precepts for public-sector regulation embodied in the Blair Labour government's official vision of public-man-agement reform, its Modernising Government White Paper of 1999. As a background to assessing the recipes for public-sector regulation in Modernising Government, the article shows that such regulation grew markedly both in the two decades up to 1997 and in the plans and activities of the Blair government from 1997 to 1999. Against that background, the design principles for public-sector regulation contained in Modernising Government are assessed. The White Paper was notable for embracing a doctrine of 'enforced self-regulation' for the public sector that involved aspirations to both more and less public-sector regulation in the future. It put its faith in a mixture of oversight and mutuality for 'regulating regulation'. But in spite of the radical-sounding tone of Modernising Government, the measures proposed appeared limited and half-hearted, and two well-known institutional design principles for regulation seemed to be missing altogether from the Blair government's view of administrative 'modernity'