Aidan O'Neill (born 1961) is a Scottish advocate, barrister, and King's Counsel.
He has pleaded almost thirty times before the Supreme Court of the United Kingdom and House of Lords, as well before the Court of Justice of the European Union and the European Court of Human Rights.
He appeared for Joanna Cherry MP before the Supreme Court of the United Kingdom in the September 2019 case relating to the prorogation of Parliament.
Career O'Neill read Law from 1978 to 1982, obtaining a First Class LL.B. (Hons.) degree from the University of Edinburgh. He then studied a Diploma in Legal Practice also at Edinburgh from 1982 to 1983.
He studied at the University of Sydney from 1983 to 1985, obtaining a First Class LL.M. (Hons.) degree where he wrote his thesis on “The Foundations and Structures of Legal Reasoning: an investigation into the role and scope of practical reasoning in our understanding of the law”.
O'Neill was called to the Faculty of Advocates in July 1987. In July 1999 he was appointed Queen's Counsel (QC) in Scotland.
He obtained a further LL.M. degree from the European University Institute after studying there between 1991 and 1992. His degree was in Comparative, International and European law and he produced a thesis titled “The Government of Judges: a study in judicial politics and the rule of law”.
O'Neill holds rare “double silk” status, having become a Scottish QC in 1999, and more recently taking silk in England and Wales in 2017.
From 1997 to 1999 O'Neill was Standing Junior Counsel to the Scottish Office Education and Industry Department.
He is a member of Ampersand Advocates in Scotland. He joined his present London chambers, Matrix Chambers of Gray's Inn, London in 2000, and became a member in 2010.
He was awarded a doctoral degree (LL.D) from the University of Edinburgh in 2012 on the basis of his work's academic merits, independent scholarship and legal substance of published books.
O'Neill was appointed Queen's Counsel in England and Wales in February 2017.
He called to the Bar of Ireland in December 2020.
He was appointed by a cross-party group of 75 MPs and peers to contest a case for judicial review against the Government in the Scottish Court of Session. He went on to receive widespread media coverage in September 2019 upon representing the group including Joanna Cherry MP against the government (represented by Advocate General for Scotland, Lord Keen QC) in the case of R (Miller) v Prime Minister; Cherry & Ors v Advocate General for Scotland.
In the case he contested the use of prorogation powers by Prime Minister Boris Johnson. He was cited in media reports as passionately arguing to the justices that the "Mother of parliaments been shut down by the father of lies".
Specialisms Ampersand Advocates describe O'Neill as having particular experience and expertise in commercial judicial review, environmental/Aarhus law and in employment/equality law. He is also specialist in EU law, in human rights law and in UK constitutional law.
Noted cases
2018 - Case C-621/18 Wightman v. Secretary of State CSOH 8 & CSIH 62 - a case regarding Article 50 TEU notification which ended up in the CJEU, who ruled the notification is unilaterally revocable by the UK 2017 - Case C-333/14 Scotch Whisky Association and others v. Scottish Ministers re minimum alcohol pricing UKSC 76; CSIH 77; EU:C:2015:845; CSIH 38; CSOH 70 – a case regarding the compatibility of the Scottish Alcohol Act 2012 with Article 34 TFEU on free movement of goods 2017 - R (Miller) v Secretary of State for Exiting the European Union UKSC 5 - a case querying if the UK Government could rely upon prerogative powers to trigger Article 50 TEU to leave the EU 2013 - Bulls v. Preddy and Hall UKSC 73 – a case about whether Christian guesthouse owners could refuse a double bed room to a civil partnership couple on grounds of religious conviction
Personal life O'Neill speaks and writes in French and Italian, and has knowledge of German.
Publications +BooksTitlePublisherYearBrexit, law and trade: a guide for the perplexedHart PublishingDue to be publishedEU law for UK LawyersHart Publishing2011Judicial Review in Scotland: a practitioner's guideHart Publishing1999Decisions of the European Court of Justice and their constitutional implicationsHart Publishing1994 +ArticlesTitlePublicationYearEU law in the Supreme Court8 UK Supreme Court Yearbook2018 Brexit, Bilateral Investment Treaties and their Enforcement17 ERA Forum (online)2018EU fundamental rights in a devolved United KingdomChapter 8, Douglas-Scott (ed.)
Research handbook on EU law and human rights (Edward Elgar Publishing, 2017) 186-2082017 Miller, Brexit and breUK-upCounsel 27-29March 2017(Dis)Enfranchisement and Free MovementChapter 4 in Koutrakos, Nic Suibhne & Syrpis (eds.) Exceptions from Free Movement Law (Hart Publishing, 2016) 53-792017 Strategic Litigation before the European courts16 ERA Forum 495-5092015 The courts, the church and the constitution revisitedChapter 46 in Burrows, Johnston & Zimmermann (eds.) Judge and Jurist: essays in memory of Lord Rodger of Earlsferry (OUP, 2013) 637-6532013 The sovereignty of the (Scottish) people: 1689 and all that18 Judicial Review 446-4632013 Back to the future? Judges, politicians and the constitution in the new Scotland18 Judicial Review 45-712013 EU law and Fundamental RightsJudicial Review 216-2472011The curtailment of criminal appeals to London15 Edinburgh Law Review 88-922011 Prosecuting Crimes Against Peace Before the Scottish CourtsJohnson & Zelter (eds.) Trident and international law: Scotland's obligations (Edinburgh: Luath Press, 2011) 177-2012011Human rights and people and societyChapter 2 in Sutherland, Goodall, Little & Davidson (eds.) The Scottish Parliament: The Early Years (Edinburgh University Press: 2010) 35-572009Limited Government, Fundamental Rights and the Scottish Constitutional TraditionJuridical Review 85-1282009Constitutional Judicial Review in Scotland – some recent developments14 Judicial Review 267-2902011 Roman Catholicism and the temptation of shari’a15 Common Knowledge (Duke University Press) 269-3152009
Awards +AwardOrganisationYearResultEU law silk of the yearLegal 5002015Silk of the yearScottish Legal Awards2017Silk of the yearScottish Legal Awards2018
References
External links Page at Matrix Chambers