Jason is widely regarded as a leading senior junior, with a diverse and busy practice. He has particular expertise in public and human rights law, public international law, competition law, EU law, sanctions, sports law, media and data protection law, and immigration law. Jason combines a strong commercial practice with an extensive publicly funded and pro bono human rights practice, drawing on his academic expertise in this area. His clients include individuals, companies, States, current and former Heads of State and Heads of Government, members of the Royal Family, UK Government Departments, international organisations and NGOs. Jason regularly appears in the highest appellate courts, including the Court of Appeal, the Supreme Court, the European Court of Human Rights, and the Court of Justice of the European Union. He has appeared in 22 cases in the Supreme Court, before the General Court and Court of Justice in over twenty-five cases, and before the European Court of Human Rights in more than a dozen cases. Jason has extensive advocacy experience, and regularly appears unled, including in the High Court and the General Court of the European Union.

Jason is ranked as a leading junior in eight practice areas in the leading independent legal directories, Legal 500, Chambers UK and Chambers Global, including Band 1 for Administrative and Public Law, Civil Liberties and Sanctions Law. Jason was shortlisted for Human Rights and Public Law Junior of the Year in the Chambers UK Bar Awards 2022 and for EU and Competition Junior of the year in the Legal 500 Awards 2020. In 2021, Jason was featured on The Lawyer's Hot 100 List, where he was described as "one of the most sought after juniors in the business". In 2018, Jason won the World's ECR's young practitioner of the year award.

Jason is a member of the Attorney General's A Panel of Counsel, the Attorney General's PIL Panel of Counsel, and the Equality & Human Rights Commission's Panel of Counsel. In 2018 he was appointed a trustee of the AIRE Centre.

In addition to this London practice, Jason is a member of the Bar of Ireland and the Law Library of Ireland.

Recent highlights of Jason's practice include:

  • acting for the lead claimants in challenge against the UK Government's Rwanda asylum plan in High Court, Court of Appeal and European Court of Human Rights ([2022] EWHC 3230)
  • acting for Rt Hon Boris Johnson MP in Privileges Committee investigation into whether the former Prime Minister misled Parliament over 'partygate' allegations.
  • acting for Ukraine in its European Court of Human Rights proceedings against Russia
  • acting for the Premier League in dispute with Newcastle Football Club regarding its sale to the Saudi Arabian Public Investment Fund
  • acting for the Duke of Sussex in judicial review challenging security-related decisions by the Government
  • acting for the BBC in various public law claims, investigations and inquiries, including the Dyson investigation into the Princess Diana interview
  • acting for Visa in its ongoing defence of multiple claims brought by retailers alleging that interchange fees charged on card transactions are anti-competitive, and breach Article 101 and Article 102 TFEU
  • acting for Volkswagen AG in the class action arising out of what is often described as "Dieselgate"
  • acting for Scania Trucks in its defence of multiple claims alleging a cartel in connection with the manufacture of medium and large trucks throughout Europe
  • acting for Annington in its judicial review challenge to decisions of the Ministry of Defence relating to enfranchisement of service family accommodation
  • acting for the Foreign Office in the first court review challenge to a UK sanctions designation
  • acting for the Law Society in its challenge to the UK Government's failure to implement the findings of the Bellamy Review into legal aid
  • acting for the Getty Museum in the European Court of Human Rights in a claim against the Government of Italy.
  • acting for former President of Kazakhstan in complaints to various UN bodies regarding arbitrary detention in Kazakhstan (including the UN Working Group on Arbitrary Detention).
  • acting for Sheikh Mohammed bin Rashid al-Maktoum, ruler of Dubai, in high-profile family court proceedings
  • acting for a mother in Supreme Court appeal considering relationship between the 1951 Refugee Convention and the Hague Convention (G(A child) [2021] 2 WLR 705)
  • acting for Foreign Secretary in defence of a claim brought by the parents of Harry Dunn, raising issues relating to diplomatic immunity and Article 2 ECHR
  • acting for Foreign Secretary in intervention in Supreme Court in the Venezuelan gold dispute
  • acting for UN Special Rapporteur on the promotion and protection of human rights and fundamental freedoms while countering terrorism in Shamima Begum citizenship appeal in Court of Appeal ([2020] 1 WLR 4267) and Supreme Court ([2021] 2 WLR 556)
  • acting for Anti-Slavery International in intervention in Court of Appeal case involving standard of proof and treatment of expert evidence
  • acting for the former Prime Minister in defending claim brought by the FDA challenging the Prime Minister's decision that the conduct of the Home Secretary did not breach the Ministerial Code.
  • advising Save the Children in relation to violations of the Convention on the Rights of Child in Myanmar, including presenting at the UN Human Rights Council
  • acting for a large number of shareholders of Banco Popular, challenging the decision of the Single Resolution Board to sell Banco Popular to Banco Santander for 1 euro in 2017

Recent comments in the directories include:

  • "Jason a fantastic barrister. He is our go-to barrister. I couldn't rate him highly enough."- Chambers & Partners, 2025
  • "Jason has a brilliant mind, allied to very strong emotional intelligence, and provides a wonderful service to instructing solicitors." - Legal 500, 2025
  • "A real star: super bright, creative, incisive and so strategic."- Legal 500, 2024
  • "The dream junior. He has real class when it comes to his advocacy."- Chambers & Partners, 2024
  • "He is just superb, he is a future star of the Bar. He's got an eye-watering work ethic and is always calm and collected."- Chambers UK, 2023
  • "Jason is absolutely first rate. He's responsive, fantastic tactically, and really sees the woods for the trees. I can't rate him highly enough." - Chambers UK, 2023
  • "Jason is incredibly intelligent, phenomenally thorough, and an accomplished all-rounded. I am in awe of the diversity of his practice."- Chambers UK, 2023
  • "His standout attributes are his unbelievable work ethic and his attention to detail. He's genuinely exceptional."- Chambers Global, 2023

Prior to joining Chambers, Jason was an associate in the commercial litigation team at Mallesons Stephen Jaques (now King & Wood Mallesons) in Australia, where he had a broad commercial litigation practice. In addition to this experience as a commercial litigation solicitor, Jason has taught and published widely in the areas of public international law, public law and human rights, and international refugee law. He is a Research Associate at the Refugee Studies Centre at the University of Oxford. His monograph, The Child in International Refugee Law was published by Cambridge University Press in 2017, and was shortlisted for the triennial Inner Temple Book Prize.

Experience

Shortlist

Public & Regulatory

Jason is recognised as a leading public law junior. He was shortlisted for Human Rights and Public Law Junior of the Year in the Chambers UK Bar Awards 2022. His clients include individuals, companies, States, current and former Heads of State and Heads of Government, members of the Royal Family, UK Government Departments, international organisations and NGOs. He regularly acts in high-profile litigation both for and against the UK Government. He has also acted in public law cases in Hong Kong, Singapore, the BVI and the Cayman Islands. Jason has particular expertise and experience in public law cases with a cross-over with commercial law, competition law and EU law. He appears regularly in the Administrative and Appellate Courts, and has been instructed in 22 cases before the Supreme Court (the majority of which have raised public law issues).

Jason is a member of the Attorney General’s A Panel of Counsel, and the Attorney General's PIL Panel of Counsel.

Cases

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Civil Liberties & Human Rights

Jason is recognised as a leading civil liberties and human rights junior. He was shortlisted for Human Rights and Public Law Junior of the Year in the Chambers UK Bar Awards 2022. His clients include individuals, companies, States, current and former Heads of State and Heads of Government, members of the Royal Family, UK Government Departments, international organisations and NGOs. He regularly acts in high-profile litigation both for and against the UK Government. Jason has particular expertise and experience in the cross-over between commercial and competition law and human rights law.

Jason’s practice is complemented by his academic experience, having taught and published widely in the areas of public law and human rights, public international law and immigration and refugee law.

In addition to publicly funded work, Jason undertakes substantial pro bono work. He has acted pro bono for UNHCR, the Office of the Children’s Commissioner, Bail for Immigration Detainees, Medical Justice, the AIRE Centre, ILGA-Europe, the Human Dignity Trust, the Equality Network and the International Commission of Jurists. He has previously been nominated for the Bar Pro Bono Unit Pro Bono Barrister of the Year.

Jason is a member of the Attorney General’s A Panel of Counsel, the Attorney General's PIL Panel of Counsel and the Equality and Human Rights Commission Panel of Counsel.

Cases

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Competition

Jason is a highly sought after senior junior in the competition law space. He is ranked as a leading competition junior in Chambers UK, Chambers Global and Legal 500. In 2019, Jason was shortlisted for EU and Competition Junior of the year in the Legal 500 awards. He is currently acting in several of the largest domestic competition cases being litigated in the United Kingdom: the Visa interchange litigation; the trucks cartel; and the “dieselgate” litigation. He has expertise in collective proceedings before the Competition Appeal Tribunal, having acted for both claimants and defendants in this area. Jason also has expertise in advising on CMA mergers and market investigations, having acted both for and against the CMA. He has also advised the Hong Kong Competition Commission in relation to its own investigations. Jason also has a particular interest and expertise in sport-related competition issues.

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EU Law

Jason has appeared in many of the leading EU law cases in both the EU and UK courts. Jason has appeared in more than 25 cases in the General Court and Court of Justice of the European Union, on issues concerning sanctions, freedom of information, financial regulation and freedom of movement. He has particular expertise in EU sanctions law (see separate entry below). Jason continues to practice in the General Court and Court of Justice via the Law Library in Ireland.

At the domestic level, Jason continues to act in many of the leading cases concerning the role of EU law in the UK post-Brexit. He has particular experience and expertise on the Withdrawal Act 2018.

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Sport

Jason is fast becoming a leading senior junior in the sports law field, particularly in cases with a cross-over with public law, competition law and public international law. Since 2020, Jason has been instructed in some of the biggest pieces of sports litigation in the UK, including by the Premier League and English Football Association. A number of Jason’s cases are confidential and cannot be listed below.

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Public International Law

Jason is a leading junior in the public international law field. He is regularly instructed in domestic and international cases that raised public international law matters, particularly issues concerning State and diplomatic immunity, foreign act of State, the interpretation of international treaties, and international sanctions. He has undertaken extensive work before the UN bodies, including the UN Human Rights Council, the UN Human Rights Committee, and the various UN working groups and Special Rapporteurs. He is regularly instructed by the Foreign Office on public international law issues, and is a member of their Panel of Public International Law Counsel. He also regularly provides pro bono advice to a number of NGOs on public international law issues, including UINHCR, Save the Children, Reprieve, and Freedom from Torture and UNHCR.

Jason is acting for the Foreign Secretary in a challenge brought by a child, alleging that the Vienna Convention on Diplomatic Relations is incompatible with Article 3 ECHR on the basis it precludes intervention in the case of domestic child abuse. Jason succeeded in the Divisional Court, and permission has been granted to the Court of Appeal.

Cases

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State and Diplomatic Immunity

Jason has particular expertise and interest in issues concerning State and diplomatic immunity. He has been instructed in many of the leading cases on these issues, and regularly advises the Foreign Office, and individuals (including current and former Heads of State and Heads of Government) on issues concerning State and diplomatic immunity. Many of the instructions are confidential. Reported cases are listed below.

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Sanctions

Jason is recognised as a leading EU and UK lawyer in sanctions-related work. He is highly sought after for his expertise in challenging and advising on EU and UK domestic sanctions. In 2018 he was awarded the World ECR Young Sanctions Practitioner of the Year Award. He has represented more than twenty-five individuals and entities in more than twenty challenges to asset-freezing regimes before both the General Court of the EU and the Court of Justice. Jason’s sanctions-related work is complemented by his academic background in public international law.

Jason also regularly appears in sanctions-related challenges in domestic Courts, both in the UK and abroad. Jason has particular experience with the sanctions regimes for Russia, Belarus, Iran, Egypt, Syria, Ukraine and Libya, and regularly advises banks, corporates and individuals on compliance issues, including the implications of sanctions to commercial transactions.

Jason regularly advises the Foreign Office and the Department of Transport on sanctions-related issues, and appeared successfully on behalf of the Foreign Office in the first court challenge to a sanctions designation under the Sanctions and Anti-Money Laundering Act 2018.

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Media & Entertainment

Jason practices in all aspects of media and entertainment law, with particular expertise in issues relating to broadcasting regulation, privacy, free speech and data protection. He regularly advises the BBC on a range of media and public law issues. He has also acted for a number of foreign broadcasters and foreign regulators. He has particular expertise on issues relating to due impartiality and freedom of expression, having acted in a number of leading cases in this area.

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Data Protection, Freedom of Information & Privacy

Jason has considerable experience advising on issues relating of data protection, freedom of information and privacy. He is regularly instructed to advise on data protection and freedom of information issues under domestic law and EU law. He has experience in challenging and defending decisions to refuse disclosure under the Freedom of Information Act 2000 and, at the EU level, Regulation No. 1049/2001. 

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Immigration

Jason has an extensive immigration practice. He appears regularly in the Court of Appeal and Supreme Court in many of the leading refugee and migration cases. He is also widely regarded as one of the world’s leading academic experts on child refugees. His the author of the monograph published by Cambridge University Press, The Child in International Refugee Law; he is regularly invited to provide guest lectures on refugee issues, including annual lectures at Harvard University; he has designed and taught a course on child refugees at the University of Oxford; and he is currently co-authoring the next edition of the Law of Refugee Status with Professor James Hathaway and Michelle Foster.

He has appeared in many of the leading immigration and citizenship cases in recent years

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Environment

Jason has a particular interest and expertise in environment cases, particularly in the context of judicial review. He has particular expertise in cases with an EU law dimension.

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Achievements

Education

BA (University of Melbourne); LLM (University of Melbourne); BCL (Dist.) (Oxon) (Commonwealth Scholar); PhD (Cantab) (W.M. Tapp Scholar and Poynton Cambridge Australia Scholar)

Prizes & Scholarships

  • WorldECR's young practitioner of the year award (2018).
  • Cambridge Yorke Prize for a PhD thesis of exceptional quality that makes a substantial contribution to its relevant field of legal knowledge.
  • Hauser Global Fellowship (to attend New York University as a Hauser Visiting Doctoral Researcher).
  • W.M. Tapp Studentship in Law (full funding to undertake PhD at Gonville and Caius College, University of Cambridge).
  • Poynton Cambridge Australia Scholarship (full funding to undertake PhD at Gonville and Caius College, University of Cambridge).
  • Commonwealth Scholarship (full funding to undertake BCL, University of Oxford).

Publications

Books

The Child in International Refugee Law (Cambridge University Press, 2017), shortlisted for the triennial Inner Temple Book Prize (2018).

Book chapters

  • “Article 10” in Philip Alston and John Tobin (eds.), The UN Convention on the Rights of the Child: A Commentary (Oxford University Press, 2018) (forthcoming).
  • “Article 22” in Philip Alston and John Tobin (eds.), The UN Convention on the Rights of the Child: A Commentary (Oxford University Press, 2018) (forthcoming).
  • “Treating like alike: The principle of non-discrimination as a tool to mandate the equal protection of refugees and beneficiaries of complementary protection” in James C. Hathaway (ed.), Human Rights and Refugee Law (Edward Elgar, 2014) (reprint).
  • “A child rights framework for assessing the status of refugee children” in Satvinder Juss and Colin Harvey (eds.), Contemporary Issues in Refugee Law (Edward Elgar, 2013) 91 – 138.
  • Co-author (with Guglielmo Verdirame), “The end of refugee camps” in Satvinder Juss (ed.), Research Companion to Migration Laws Theory and Policy (Ashgate, 2013) 471 – 488.

Articles

  • “The best interests of the child principle as an independent source of protection” (2015) 64(2) International Comparative Law Quarterly 327
  • Co-author (with Justice Anthony North and James C. Hathaway), “Roundtable on the Future of the Refugee Convention Supervision” Journal of Refugee Studies (2013) (forthcoming).
  • Co-author (with Sarah Spencer CBE), "Equality for All? The Relationship between Immigration Status and the Allocation of Rights in the United Kingdom" (2012) 2 European Human Rights Law Review 160 – 175.
  • Co-author (with James C. Hathaway), “Queer cases make bad law” (2012) 44(2) New York University Journal of International Law and Politics 315-389 [published as lead article in symposium, with responses from Sir Richard Buxton, Ryan Goodman, John Tobin, David Frank, Jenni Millbank, Deborah Anker, Sabi Ardalan and Guglielmo Verdirame].
  • Co-author (with Michelle Foster), “A failed case of legal exceptionalism? Refugee status determination in Australia's 'excised' territories” (2011) 23(4) International Journal of Refugee Law 583 – 631.
  • “Treating like alike: The principle of non-discrimination as a tool to mandate the equal protection of refugees and beneficiaries of complementary protection” (2010) 34(1) Melbourne University Law Review 181 – 229. 
  • Co-author (with Kate Purcell), “Refugee processing freeze: Unlawful and practically unsound” (2010) 35(2) Alternative Law Journal 60 – 61.
  • “Keeping the cat out of the bag: The interaction between litigation privilege and the service of witness statements” (2010) 29 Civil Justice Quarterly 48 – 72.
  • “The service of witness statements and litigation privilege: ACCC v Cadbury” (2009) 13 The International Journal of Evidence and Proof 335 – 341.
  • "Medically mediated reproduction: Posthumous conception and the best interests of the child" (2007) 15 Journal of Law and Medicine 450 – 468. 

Research & Teaching

Jason has undertaken postgraduate study at the University of Melbourne, University of Oxford, University of Cambridge and New York University. He received his doctorate from the University of Cambridge for his thesis, “The Child In International Refugee Law”. His research has focused principally on public international law, public law and human rights, and international refugee law, and he has taught in these areas at the University of Cambridge, the University of Oxford, the University of London and New York University. 

In 2010 Jason founded the Cambridge Pro Bono Project, which has, since its establishment, facilitated the involvement of hundreds of postgraduate students in various pro bono projects.

In 2011 Jason was a Visiting Fellow at New York University working under the supervision of Professor Philip Alston, where he was also involved in supervising students undertaking the International Human Rights Fellowship. In 2010 Jason was a Research Associate at Makerere University in Kampala, where he undertook research on unaccompanied refugee children, predominately from the Democratic Republic of the Congo.

Jason is presently a Research Associate at the Refugee Studies Centre at the University of Oxford.

Jason is regularly invited to speak and present at conferences and workshops both domestically and overseas, particularly on issues relating to human rights and international refugee law. He has recently delivered lectures in London, Oxford, Cambridge, Lund, Stockholm, Geneva and Boston. He has acted as a consultant to the Centre of Migration, Policy and Society at the University of Oxford, and the Diana, Princess of Wales Memorial Fund. 

Jason is a trustee of the AIRE Centre.

Memberships

  • Administrative Law Bar Association
  • Human Rights Lawyers Association
  • Bar European Group
  • Immigration Law Practitioners Association
  • Commercial Bar Association 
  • Employment Lawyers Association
  • Employment Law Bar Association
  • British Institute of International and Comparative Law
  • International Law Association
  • European Society of International Law
  • American Society of International Law

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