This thesis examines the developing role of television channels in the delivery of public service broadcasting in Britain, 1996-2002. Starting from a hypothesis that channels are distinct television products in their own right and increasingly important in organising how broadcasters think about their audiences, it argues that channels have identities expressed through their schedules and determined by their relationship to genre and target audience. Based on research at the BBC (from 1998 - 2002), involving interviews with key staff and the analysis of BBC documents, this study examines the television broadcasting functions of commissioning, scheduling, marketing and audience research. It illustrates how these activities created specific identities for television channels and how these identities shaped the programming that reached television screens. It reveals how channels became increasingly important in the television landscape as buyers in a more demand-led commissioning economy and acted as a focus for the creation of media brands. It then discusses how the evolution of a channel portfolio enabled each channel to play a specific role in fulfilling public service obligations and looks at how different models of audience emerged in relation to the different public service television channels, charting the decline of the mass audience and the emergence of the visualisation of audiences in a more individualised way. The thesis concludes by addressing some implications of these developments. It looks at how the different models of audience in circulation affect debates about quality television, and how changing ideas about the construction of public service channels may impact on the regulation of broadcasting. Finally, it explores the effect of multiple channels, each targeted at specific audiences, on the concept of a unitary public sphere and speculates that channels have the potential to underpin the creation of multiple imagined communities.