Jack Williams

Call 2015
MA(Cantab) BCL (Oxon)

+44 (0)20 7405 7211

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Jack practises across all Chambers’ specialisms, with a particular focus on competition law, procurement law, public law and commercial law (including sports). Recent notable reported cases include R (Miller and Dos Santos) v Secretary of State for Exiting the European Union [2017] UKSC 5 (acting for one of the interested parties in the Article 50 litigation at both Divisional Court and Supreme Court levels) and Dorothy Gibson v Pride Mobility Products Ltd [2017] CAT 9 (acting for the respondent in the first opt-out class action in UK competition proceedings).

Before qualifying as a Barrister, Jack was a College Lecturer at Brasenose College (University of Oxford) where he taught Administrative Law and Constitutional Law. Jack has also undertaken a traineeship at the Court of Justice of the European Union with Judge Vajda (British Judge), and a six-month secondment in the Bank of England’s Legal Directorate’s EU Withdrawal Unit. He is a co-editor (with Professors Mark Elliott and Alison Young) of a collection entitled: “The UK Constitution after Miller: Brexit and Beyond.

Jack graduated from the University of Oxford (Hertford College) in 2014 with a Distinction in the BCL masters in Law (ranked 2nd in the year). Before that he graduated from the University of Cambridge (St Catharine’s College) in 2012 with a First Class Degree in Law. Jack was awarded University prizes for coming top of the year in Administrative Law (Cambridge, 2011), Labour (Employment) Law (Cambridge, 2012), and Comparative Public Law (Oxford, 2014).

  • Competition Law

    Jack was junior counsel for the respondent in the first “opt-out” class action competition proceedings brought under the new UK private damages regime introduced by the Consumer Rights Act 2015 (Dorothy Gibson v Pride Mobility Products Ltd [2017] CAT 9). More information is available here and here.

    His current instructions include:

    • T-286/09 RENV – Intel Corporation v Commission: instructed by Intel in relation to the remittal of its application to the General Court following Intel’s successful appeal to the CJEU concerning alleged infringements of Article 102 (abuse of dominance)
    • Google: instructed by Google in relation to the European Commission’s ongoing investigation into certain of its business practices in the search and advertising.

    Jack’s clients have included both authorities and private multi-national companies. He has advised on a range of competition law matters, including:

    • Abuse of dominance (both UK and EU)
    • Agency issues
    • Anti-competitive agreements (both UK and EU)
    • Class actions
    • Consumer protection legislation
    • European Commission investigations
    • Fines and penalty calculations
    • Jurisdictional disputes
    • Single economic entity doctrine
    • Warrants
  • Public Law (UK and EU)

    Due to his academic and teaching background, Jack has experience and expertise beyond his date of Call in a range of public law matters (in both UK and EU law). He has already been instructed in high profile public law litigation:

    • R (Miller and Dos Santos) v Secretary of State for Exiting the European Union [2017] UKSC 5 – junior counsel for one of the Interested Parties (Pigney and others: “The People’s Challenge”) in the Article 50 Brexit litigation at both Divisional Court and Supreme Court levels. The case concerned whether Parliamentary involvement was necessary to trigger any UK withdrawal from the EU or if mere use of executive power (under any subsisting prerogative power) was sufficient. More information is available here.
    • AI and XH v Secretary of State for the Home Department [2016] EWHC 1898 (Admin) – junior counsel for one of the Claimants (AI) at the Divisional Court level in his judicial review concerning whether the royal prerogative to withdraw a British Citizen’s passport had been abrogated by the Terrorism Prevention and Investigation Measures Act 2011 or was lawfully exercised in any event. More information is available here.
    • BAT Industries Plc (and others) v HMRC (TC/2015/06960) – Jack was a junior counsel for HMRC, successfully defending a challenge under EU, ECHR and domestic common law to the provisions of Part 8C (“the restitution interest provisions”) of the Corporation Tax Act 2010 before the First-tier Tribunal. More information is available here. Jack is instructed by HMRC in the BAT’s appeal to the Upper Tribunal.

    Jack has advised both public and private clients on a range of constitutional matters arising out of Brexit, including in relation to: the Article 50 process, the EU Withdrawal Bill, nationalising (or on-shoring) the acquis, the use of the royal prerogative, acquired EU rights, and the Withdrawal Agreement. Jack has spoken about these, and related, topics at various events. He is the co-editor of a book on the constitutional implications of the Miller judgment (with Professor Mark Elliott and Professor Alison Young): available here.

    Whilst a stagiaire at the Court of Justice of European Union, Jack worked on cases including: Kadi II (the effect of European procedural rights), Pringle (the validity of the European Stability Mechanism), Abdulrahim (continuing interest to bring an action for annulment), and Inuit I (the definition of regulatory acts in Article 263 TFEU for the purposes of standing).

  • Procurement Law

    Jack has been instructed on both claimant and defendant sides in major procurement litigation, for example:

    • Bombardier Transportation Ltd v Merseytravel – Jack was instructed by the defendant (led by Philip Moser QC and Valentina Sloane) to defend a damages claim in relation to contracts for the design, build and maintenance of rolling stock and the modernisation of maintenance depots.
    • CAF v High Speed 2 – Jack is instructed by the claimant to challenge the pre-qualification stage of the procurement for the provision of rolling stock and associated services for the new high-speed railway known as HS2.

    Jack has experience of mediation in procurement dispute contexts.

  • Commercial and Regulatory Law

    The great majority of Jack’s work includes a commercial and regulatory element. In particular, Jack’s competition law, procurement law and sports law practices involve a considerable amount of commercial and contractual analysis.

    Jack has also sat as an Arbitrator, appointed by Ofwat, in a dispute under the Water Industry Act 1991, and has advised on the Arbitration Act 1996.

  • Sports Law

    Jack has advised and assisted on a range of sports matters, particularly in a football context. He has advised both clubs and private individuals in relation to settlement agreements, stay applications, strike out applications, arbitration proceedings and FA disciplinary proceedings concerning matters such as: agent fees, player transfers, contractual disputes and allegations of fraud and unlawful means conspiracy.

    Jack is currently assisting Michael Armitage who is instructed by a former employee of a major football club in High Court proceedings raising issues of unlawful means conspiracy and fraud.

    During pupillage, Jack assisted Paul Harris QC and Fiona Banks representing a Premiership football manager in respect of contractual disputes. He has recently assisted Paul Harris QC in preparation for FA disciplinary proceedings, and regards a private settlement agreement.

  • Trade, Tax and Customs

    Since the EU Referendum outcome, Jack has experience of advising on international trade options and WTO law, with a particular focus on GATS and financial services post Brexit (including topics such as: FTAs under Article V GATS, dispute settlement mechanisms, GATS Schedules of Commitments, mutual recognition agreements under Article VII GATS, the prudential carve out in the Financial Services Annex to GATS, and the jurisdiction of the ECJ in relation to international agreements).

  • Publications


    • The UK Constitution after Miller: Brexit and Beyond (M Elliott, J Williams and A Young eds) (Hart, 2018)


    • “The Miller tale: an introduction” in The UK Constitution after Miller: Brexit and Beyond (M Elliott, J Williams and A Young eds) (Hart, 2018)
    • “Prerogative Powers After Miller: An Analysis in Four E’s” in The UK Constitution after Miller: Brexit and Beyond (M Elliott, J Williams and A Young eds) (Hart, 2018)
    • “Proportionality in English Administrative Law” in The Judge and the Proportionate Use of Discretion: A Comparative Administrative Law Study (Sofia Ranchordás and Boudewijn de Waard eds) (Routledge, 2015)


    • “Some things money cannot buy – lessons learned from the latest judgment under the UK’s new regime for collective competition law claims: Merricks v Mastercard Inc” (2018) 37(1) Civil Justice Quarterly 48-61
    • “Brexit and EU Sports Law” Global Sports and Taxation Reports (No 1, March 2017)
    • “The protean principle of proportionality: how different is proportionality in EU contexts?”, (2016) 75(2) Cambridge Law Journal 186
    • “‘Well, that’s a relief (from sanctions)!’ —Time to Pause and Take Stock of CPR r.3.9 Developments within a General Theory of Case Management”, (2014) 33(4) Civil Justice Quarterly 394

    Blog posts

    • “Miller and the Human Rights Act 1998: can the Government withdraw the UK from the ECHR by the royal prerogative?”, (2017) Practical Law’s Public Sector Blog
    • “The Supreme Court’s approach to prerogative powers in Miller: an analysis in four e’s”, (2017) UK Constitutional Law Blog
  • Academic background

    Dover Grammar School for Boys, 2002 – 2009

    First Class Degree in Law – University of Cambridge, 2012

    Distinction in the BCL (Masters in Law) – University of Oxford, 2014

    Outstanding in the BPTC – BPP University, 2015

    Awards and prizes:

    1) Bar Professional Training Course: BPP & Gray’s Inn

    Arden Scholarship (Gray’s Inn), 2015

    Bedingfield Scholarship (Gray’s Inn), 2014

    Residential Scholarship (Gray’s Inn), 2014

    Excellence Award (BPP), 2014

    2) Postgraduate: Oxford University, 2014

    Vinerian Proxime Accessit Scholarship, 2014 (for coming overall 2nd in the year)

    The University’s Prize for Comparative Public Law, 2014 (for coming top in the year)

    3) Undergraduate: Cambridge University

    The University’s ‘Littleton Chambers Prize for Labour Law’, 2012 (for coming top in the year)

    The University’s ‘E.C.S Wade Prize for Administrative Law’, 2011 (for coming top in the year)

    Ms Payne (1610) Scholarship, 2012

    The College’s ‘Adderley Prize for Law’, 2012

    The College’s ‘Lauterpacht Prize for International Law’, 2011

    The College’s ‘Simmons and Simmons Prize for Constitutional Law’, 2010

    Gooderson Memorial Scholarship, 2013

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