Search
photo of Marios Costa

Marios Costa

Senior Lecturer

The City Law School Academic law programmes

Contact details

About

Overview

Dr Marios Costa is a Senior Lecturer at the Institute for the Study of European Law (ISEL), The City Law School, City St George's, University of London. He was previously a Visiting Scholar at the Centre for European Legal Studies (CELS), University of Cambridge. He is also co-author of Steiner & Woods EU Law (Oxford University Press), one of the leading and most widely used books on European Union law, with a new edition forthcoming in 2027.

He is currently working on a book examining the legal dimensions of Brexit and the evolving relationship between the United Kingdom and the European Union. This research project explores the constitutional and regulatory challenges arising from the UK's withdrawal from the EU, as well as the legal frameworks that continue to govern cooperation between the EU and the UK. This book analyses how Brexit has reshaped concepts of sovereignty, market access, governance, and dispute settlement, while assessing its broader implications for European integration and the future development of EU law.

Marios's principal research interests lie also in the areas of accountability, transparency, and governance within the European Union. In his monograph, The Accountability Gap in EU Law (Routledge, 2017), he examines the constitutional challenges posed by the growing role of EU agencies, committees, and expert groups in the Union's decision-making processes. His work explores how accountability mechanisms can be strengthened within the EU's evolving system of governance, with particular emphasis on institutional oversight, democratic legitimacy, and constitutional reform. His broader research examines EU constitutional law, institutional governance, the regulation of digital markets and services, and the legal framework governing relations between the European Union and third countries.

He received an LLM in European Union Law and a PhD from the University of Essex. 

Qualifications

  • Bachelor of Laws (LL.B), Aristotle University of Thessaloniki, Greece
  • Master of Law (LL.M) (European), University of Essex, United Kingdom
  • Ph.D. in Law, University of Essex, United Kingdom

Memberships of professional organisations

  • Member, Cyprus Bar Association (non-practising)

Publications

Publications by category

Books (5)

  • Costa, M. and Peers, S. (2027). Steiner and Woods EU Law. Oxford: Oxford University Press.
  • Costa, M. and Peers, S. (2023). Steiner and Woods EU Law. Oxford University Press. ISBN 9780192884534.
  • Costa, M. (2020). Steiner and Woods EU Law (with S, Peers). Oxford University Press. ISBN 9780198853848.
  • Costa, M. (2017). The Accountability Gap in EU law. Routledge. ISBN 9781138939318.
  • Costa, M. (2017). Steiner and Woods EU Law (with L, Woods and P, Watson). Oxford University Press.

Chapters (12)

  • Costa, M. (2027). Judicial Review of EU acts. In Biondi, A. and Stefan, O. (Eds.), Elgar Encyclopedia of European Law Cheltenham, UK: Edward Elgar Publishing. ISBN 9781800885233.
  • Costa, M. and Peers, S. (2027). Delegated measures under the Digital Services Act. In Woods, L. and Twigg-Flesner, C. (Eds.), The Digital Services Act: A Commentary Cheltenham, UK: Edward Elgar Publishing Ltd. ISBN 9781035315703.
  • Costa, M. and Peers, S. (2027). Implementing Measures under the Digital Services Act. In Woods, L. and Twigg-Flesner, C. (Eds.), The Digital Services Act: A Commentary Cheltenham, UK: Edward Elgar Publishing. ISBN 9781035315703.
  • Costa, M. (2020). Accountability through Transparency and the role of the Court of Justice. In Hirsch Ballin, E., van der Schyff, G. and Stremler LLM, M. (Eds.), European Yearbook of Constitutional Law 2019: Judicial Power: Safeguards and Limits in a Democratic Society T.M.C. Asser Press. ISBN 9789462653580.
  • Costa, M. (2017). What is the future for accountability in the EU? Concluding remarks. ACCOUNTABILITY GAP IN EU LAW (pp. 112-115). ISBN 9781138939318.
  • Costa, M. (2017). The invisible hand of the EU committee-based system The case of delegated and implementing acts. ACCOUNTABILITY GAP IN EU LAW (pp. 76-96). ISBN 9781138939318.
  • Costa, M. (2017). The Accountability Gap in EU Law Introduction. ACCOUNTABILITY GAP IN EU LAW (pp. 1-+). ISBN 9781138939318.
  • Costa, M. (2017). The access to documents regime in the EU. ACCOUNTABILITY GAP IN EU LAW (pp. 23-60). ISBN 9781138939318.
  • Costa, M. (2017). Introduction and preliminary remarks European Union accountability. ACCOUNTABILITY GAP IN EU LAW (pp. 5-12). ISBN 9781138939318.
  • Costa, M. (2017). Accountability within the Commission. ACCOUNTABILITY GAP IN EU LAW (pp. 13-22). ISBN 9781138939318.
  • Costa, M. (2017). Accountability through locus standi and the role of the Court of Justice. ACCOUNTABILITY GAP IN EU LAW (pp. 97-111). ISBN 9781138939318.
  • Costa, M. (2017). Accountability of the EU decentralised agencies. ACCOUNTABILITY GAP IN EU LAW (pp. 61-75). ISBN 9781138939318.

Internet publications (4)

  • Costa, M.(2019).Accountability and Independence of the Governors of National Banks: Any role for the Court of Justice of the European Union? EU Law Analysis Blog.
  • Costa, M. and Fahey, E.(2016).Accountability and Transparency of the Executive & Brexit under UK and EU Law. News from City, University of London.
  • Costa, M.(2015).Accountability and Defenestration: The Dalli Saga. EU Law Analysis Blog.
  • Costa, M.(2014).The EU’s Financial Supervisory Authorities: Mind the Accountability Gap. EU Law Analysis Blog.

Journal articles (8)

Working paper

Professional activities

Events/conferences (6)

  • 'Accountability through transparency and the role of the Court of Justice'. Centre for European Legal Studies, Faculty of law, University of Cambridge (2015).
  • European Agencies' Accountability Revisited. Socio-legal Studies Association Annual Conference, University of Sussex, Sussex, UK (2011).
  • Do Articles 230 and 234 of the European Community Treaty provide a complete system of remedies? De Montfort University, Leicester, UK (2009).
  • Accountability Deficits within the Union: The Cresson Case. Society of Legal Scholars Annual Conference, London School of Economics and Political Science, London, UK (2008).
  • European Accountability: The Conceptual Framework. Socio-legal Studies Association Annual Conference, University of Manchester, Manchester, UK (2008).
  • Governance and Transparency in the European Union. School of Law Seminars, University of Essex, Essex, UK (2008).

Keynote lecture/speech

  • 'Beware of the Courts Bearing Gifts'. The Dutch House of Representatives (2016).

Online articles (4)