David Marquand is a leading commentator on UK politics and political history. After an early career as a journalist and Labour MP, he has occupied a series of academic posts, including a period as Principal of Mansfield College, Oxford. His major subject has been the paradoxes of the British Left and the dilemmas of social democracy and liberalism within a fragmented party system. His important book The Progressive Dilemma argued that Labour and the Liberals had crucial commonalities, and that the tragedy of the twentieth century was their artificial division into separate parties. He has also worked on the disintegration of the post-war consensus, analysing the challenges to the public sphere and citizenship posed by Thatcherite political economy and the policies of New Labour. Polity has published his books The New Reckoning: Capitalism, States and Citizens and Decline of the Public: The Hollowing Out of Citizenship.