Aidan O'Neill KC (born 1961) is a Scottish

advocate An advocate is a professional in the field of law. Different countries' legal systems use the term with somewhat differing meanings. The broad equivalent in many English law–based jurisdictions could be a barrister or a solicitor. However, ...

barrister A barrister is a type of lawyer in common law jurisdictions. Barristers mostly specialise in courtroom advocacy and litigation. Their tasks include taking cases in superior courts and tribunals, drafting legal pleadings, researching law and ...

, and King's Counsel. He has pleaded almost thirty times before the

Supreme Court of the United Kingdom The Supreme Court of the United Kingdom (initialism: UKSC or the acronym: SCOTUK) is the final court of appeal in the United Kingdom for all civil cases, and for criminal cases originating in England, Wales and Northern Ireland. As the Unite ...

and

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, as well before the Court of Justice of the European Union and the

European Court of Human Rights The European Court of Human Rights (ECHR or ECtHR), also known as the Strasbourg Court, is an international court of the Council of Europe which interprets the European Convention on Human Rights. The court hears applications alleging that a ...

. He appeared for

Joanna Cherry Joanna Catherine Cherry (born 18 March 1966) is a Scottish politician and lawyer serving as the Member of Parliament (MP) for Edinburgh South West since 2015. A member of the Scottish National Party (SNP), she was the party's Shadow Home Se ...

MP before the

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 A diploma is a document awarded by an educational institution (such as a college or university) testifying the recipient has graduated by successfully completing their courses of studies. Historically, it has also referred to a charter or offici ...

also at Edinburgh from 1982 to 1983. He studied at the

University of Sydney The University of Sydney (USYD), also known as Sydney University, or informally Sydney Uni, is a public research university located in Sydney, Australia. Founded in 1850, it is the oldest university in Australia and is one of the country's si ...

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 The European University Institute (EUI) is an international postgraduate and post-doctoral teaching and research institute and an independent body of the European Union with juridical personality, established by the member states to contribu ...

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 Matrix Chambers is a barristers' chambers in Gray's Inn London, Brussels, and Geneva. Founded in April 2000 by 22 barristers from 7 different chambers, it now has over 90 independent and specialist lawyers who work throughout the UK and interna ...

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 The Court of Session is the supreme civil court of Scotland and constitutes part of the College of Justice; the supreme criminal court of Scotland is the High Court of Justiciary. The Court of Session sits in Parliament House in Edinburgh ...

. 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 His Majesty's Advocate General for Scotland ( gd, Àrd-neach-tagraidh an Rìgh airson Alba) is one of the Law Officers of the Crown, whose duty it is to advise the Crown and His Majesty's Government on Scots law. The Office of the Advocate Gener ...

, 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 A prime minister, premier or chief of cabinet is the head of the cabinet and the leader of the ministers in the executive branch of government, often in a parliamentary or semi-presidential system. Under those systems, a prime minister is not ...

Boris Johnson Alexander Boris de Pfeffel Johnson (; born 19 June 1964) is a British politician, writer and journalist who served as Prime Minister of the United Kingdom and Leader of the Conservative Party from 2019 to 2022. He previously served as F ...

. 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

018 018 may refer to *Air Canada Flight 018, an airline flight from Hong Kong to Vancouver, Canada, illegally boarded by a Chinese man wearing a disguise in 2010 *Area code 018, a telephone area code in Uppsala, Sweden *BMW 018, an experimental turboje ...

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

017 Seventeen or 17 may refer to: *17 (number), the natural number following 16 and preceding 18 * one of the years 17 BC, AD 17, 1917, 2017 Literature Magazines * ''Seventeen'' (American magazine), an American magazine * ''Seventeen'' (Japanese ...

UKSC 76;

016 HV-016 is a former military unit of Norway, that was a part of the Home Guard. It was established after 1985 to "stop terror- or sabotage actions that could weaken or paralyze Norway's ability to mobilize its military and its ability to resist". ...

CSIH 77; EU:C:2015:845;

014 014 may refer to: * Argus As 014 * BIND-014 * 014 Construction Unit * Divi Divi Air Flight 014 * Pirna 014 * Tyrrell 014 The Tyrrell 014 was a Formula One car, designed for Tyrrell Racing by Maurice Philippe for use in the season. The cars wer ...

CSIH 38;

013 013 is a music venue in Tilburg, the Netherlands. The venue opened in 1998 and replaced the ''Noorderligt'', the ''Bat Cave'' and the ''MuziekKantenWinkel''. 013 is the largest popular music venue in the southern Netherlands. There are two concer ...

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

Awards

References

External links

Page at Matrix Chambers
{{DEFAULTSORT:ONeill, Aidan 1960 births Living people Lawyers from Edinburgh Alumni of the University of Edinburgh Members of Gray's Inn British King's Counsel