Professor Champion is a strong proponent of public history. He has presented or appeared in several TV and radio shows about British history, including the Channel 4 drama documentary The Great Plague in 2001, the ITV documentary series Kings and Queens in 2003 and the BBC Four programme Harlots, Housewives and Heroines: A 17th Century History for Girls - Act One: At Court in 2012. He has made history features for BBC Radio 3 and 4 on the Glorious Revolution of 1688, the execution of Charles I, the history of duelling and the history of friendship. He is currently (2016) President of the Historical Association and a member of its Committee of Public History. During his time as the head of the history department at Royal Holloway, the college began offering a Master of Arts programme in Public History in partnership with external heritage and media institutions.
Champion holds a PhD from Cambridge University. His research and teaching interests include the history of early modern ideas, blasphemy and irreligion in early modern Europe, Thomas Hobbes, Biblical criticism, urban disease, the history of reading and scholarship, and the use of information technology in the study of history. He is currently working on the thought and influence of Thomas Hobbes' radical criticism of public religion and its relationship with the early Enlightenment.
Champion stepped down as the head of the history department at Royal Holloway in 2010, but has continued to teach at the college.
- Republican Learning. John Toland and the crisis of Christian culture, 1696-1722 (Manchester University Press, 2003)
- John Toland Nazarenus 1718 (edited) (Oxford: Voltaire Foundation, 1999)
- "Bibliography and Irreligion: Richard Smith’s ‘Observations’", The Seventeenth Century X (1995)
- "John Toland: The Politics of Pantheism", Revue de Synthèse 4 ser (1995).
- "Relational Databases and the Great Plague" in History and Computing (1993)
- "Legislators, Impostors and the Politic Origins of Religion: English Theories of Imposture from Stubbe to Toland" in RH Popkin, S Berti (eds.) Heterodoxy, Spinozism and Freethought (Klewer, 1996)
- Europe’s Enlightenment and National Historiographies Europa (1993)
- London’s Dreaded Visitation: The Social Geography of the Great Plague 1665 (London: Historical Geography Research Monograph No. 31, 1995)
- Epidemic Diseases in London (edited) (London, 1993)
- The Pillars of Priestcraft Shaken: The Church of England and its Enemies 1660–1730 (Cambridge, 1992)