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Aidan O'Neill QC


Aidan O’Neill QC is dual-qualified as a barrister in England and Wales and as a practising advocate in Scotland. He has appeared as senior counsel before, among other tribunals, the UK Supreme Court, the Judicial Committee of the Privy Council, the House of Lords, the Court of Justice of the European Union and the European Court of Human Rights. 

He is “a leading EU lawyer” (Chambers Guide, 2013 edition). His EU for UK Lawyers (Hart Publishing Second edition, 2011) has been described as a “compelling text”, “readable and user-friendly”, “lively and insightful”, and “a comprehensive and substantial work giving an overall view of the application of European Union law at the national level” constituting “an essential reference book for every legal practitioner in the UK”. The Legal 500 (2012 edition) ranks him as a leading silk at the London Bar in EU and competition law observing that “the ‘fantastic’ Aidan O’Neill QC (Scot) is ‘perceptive and thorough, with a good understanding of clients’ needs’ and that ‘the Supreme Court is his natural environment’”.

Aidan O’Neill also has a very strong practice in public law and judicial review. The Chambers Guide ranks him as a leading counsel in administrative and public law both at the London Bar and at the Scottish Bar stating that (2012 edition): “Instructing solicitors single out Aidan O'Neill QC as an ‘incredibly hard worker’” and that “he has a strong interest in the inter-relationship between EU, domestic and human rights laws and enjoys an enviable reputation” and (2013 edition) that he “is recognised for displaying ‘a phenomenal knowledge and understanding’ when handling cases”. The Chambers Guide also rates him as a leading counsel at the London Bar and the Scottish Bar in civil liberties and human rights stating (2012 edition) that “a big name in both London and Edinburgh, he is a man who amazes solicitors both with his output and his in-depth knowledge of the ECHR” and (2013 edition) noting that “the ‘extremely talented’ Aidan O'Neill QC is dual-qualified to practise in Scotland and England, and is widely recognised as one of the leaders of the Scottish Bar”. The Legal 500 (2011 edition) says of him that that he has an “astonishing breadth of knowledge and a bravery to argue cutting edge points”.     And The Legal 500 (2012 edition), in ranking him as a leading silk at the London Bar in civil liberties and human rights, describes him as ‘unrivalled in his depth and breadth of knowledge in the civil liberties field’.”

Finally the Chambers Guide 2012 lists him as a leading counsel in Scotland for employment matters, noting that “although perhaps best known for his stellar human rights work Aidan O'Neill QC has a significant employment law practice. He is a ‘fantastic lawyer’ who is particularly strong when dealing with employment cases that have a human rights element.”

In addition to law degrees from Edinburgh and Sydney universities, Aidan O’Neill holds a Master’s degree in European and International and Comparative law from the European University Institute, Florence. In the academic year 2007-2008 he was the inaugural University Center for Human Values/Law and Public Affairs Fellow in Law and Normative Inquiry at Princeton University. In 2009 he was appointed to be Chairman of the Edinburgh Centre for Constitutional Law and, in the same year, was made an Honorary Fellow in the School of Law, University of Edinburgh.  

He has written three legal text books to date: EU for UK Lawyers (Second edition, 2011), an exposition of EU law from a fundamental rights perspective jurisprudence which analyses its impact on a wide variety of UK domestic fields of legal practice including competition law and public procurement, criminal law, immigration and asylum, intellectual property, freedom of information, equality law, employment protection, workplace health and safety, environmental law, consumer law, private international law, taxation, trade law, and agriculture and fisheries; Decisions of the European Court of Justice and their constitutional implications (1994), a survey of the manner in which the CJEU created the conditions for a European constitution and has transformed the UK constitution; and Judicial Review in Scotland: a practitioner’s guide (1999). He has also contributed chapters to a number of legal books, and is the author of many talks and articles in academic journals, particularly in the field of human rights, constitutional law and EU law.

In 2008 taught a semester-long seminar course at Princeton University on the inter-relationship between EU law, human rights law and public international law and issues. In 2009 and 2010 he taught a human rights elective seminar course in the Diploma in Legal Practice at Edinburgh Law School. In 2012 he was awarded the higher degree of Doctor of Laws (LL.D.) by the University of Edinburgh on the basis of his legal publications.

Court Experience

Aidan O'Neill QC has appeared as senior counsel before the European Court of Justice, the Judicial Committee of the Privy Council, the House of Lords and UK Supreme Court, the Court of Session (Inner and Outer House), and the High Court of England & Wales (Administrative Division), as well as before the sheriff courts in Scotland and the county court in England and Wales. He also has significant experience in high profile Fatal Accident Inquiries.

A full list of his significant cases is noted in his CV (opens as .pdf).

Professional appointments

  • Standing Junior Counsel to the Scottish Office Education and Industry Department: 1997 to 1999
  • Associate Member, Matrix Chambers, London: 2000 to 2010.
  • Full Member, Matrix Chambers, London: 2010 to date.

Aidan O'Neill QC

Contact Details

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