Mark grew up close to the Lake District in Cumbria and studied Law at Queens' College, Cambridge, in the mid-1990s, first as an undergraduate, and then as a PhD student. His doctoral research concerned the constitutional justification for judicial review in English law, and was awarded a University of Cambridge Yorke Prize for a PhD thesis of exceptional quality that makes a substantial contribution to its relevant field of legal knowledge. During his time as a research student (and after) Mark worked as a lecture-writer for the then Lord Chancellor, Lord Irvine of Lairg, drafting several high-profile, published lectures.
Mark has taught at the University of Cambridge since 2000, becoming Professor of Public Law in the Faculty of Law in 2015. He is also a Fellow of St Catharine's College, Cambridge and a member of the Faculty of Law's Centre for Public Law. He was the Legal Research Foundation Visiting Scholar at the University of Auckland, New Zealand, in 2011. Together with John Bell and Jason Varuhas, Mark co-founded the biennial series of international Public Law Conferences, the first two of which took place in Cambridge in 2014 and 2016, bringing together leading scholars, judges and practitioners from across the common law world. In 2015, Mark was appointed Legal Adviser to the House of Lords Constitution Committee. He serves on the editorial board of the Cambridge Law Journal and on the advisory board of Public Law Review.
Mark has published across a broad range of topics within the general field of public law, addressing areas including judicial review, devolution, local government, parliamentary sovereignty, judicial control of prerogative power, public sector ombudsmen, tribunals, public inquiries, the constitutional implications of the "war on terror" and the nature and implications of bills of rights. His work is animated by an underlying concern to draw together constitutional theory and public law doctrine in ways that allow each to gain from and feed into the other. The seeds of this approach to the discipline are contained in Mark's first book, The Constitutional Foundations of Judicial Review. Based on his doctoral thesis, the book is concerned with the interface between constitutional theory and the courts’ powers of judicial review. He is also the co-author of Administrative Law (with Jason Varuhas) and Public Law (with Robert Thomas) and the co-editor of Effective Judicial Review: A Cornerstone of Good Governance (with Christopher Forsyth, Swati Jhaveri, Michael Ramsden, and Anne Scully-Hill), The Scope and Intensity of Substantive Review: Traversing Taggart’s Rainbow (with Hanna Wilberg), The Cambridge Companion to Public Law (with David Feldman), Public Law Adjudication in Common Law Systems: Process and Substance (with John Bell, Jason Varuhas and Philip Murray) and The Unity of Public Law? Doctrinal, Theoretical and Comparative Perspectives (with Jason Varuhas and Shona Wilson Stark).
As well as research and writing, Mark very much enjoys teaching; in 2010, he was awarded a University of Cambridge Pilkington Prize for excellence in teaching. He is the author of Public Law for Everyone, a blog for public lawyers, Law students and others interested in the subject. Mark has also been in involved in training members of the judiciary, giving lectures to Judges of the Immigration and Asylum Chamber of the Upper Tribunal and the Administrative Appeals Chamber of the Upper Tribunal.