This chapter explores the central government departments, executive agencies, and other public bureaucracies in operation in the UK today, such as those in local and territorial governments. These bodies help make and implement public policies and run public services. The chapter reviews more general work on bureaucracy and public administration, and sets out the theory of politician–bureaucrat relationships (going back to the principal–agent model), before addressing the classic question of civil service influence over public policy. It then takes account of the diversity of bureaucratic organizations operating in Britain today. The chapter also looks at the evidence of how politicians manage to satisfy their political objectives through delegating authority to these bodies.