Tristan Jones KC

Tristan led the team for Spreadex bringing a judicial review of a CMA merger decision. The decision was quashed and remitted and is currently under re-consideration.

Tristan acted for the CMA defending a judicial review concerning the CMA's power to require companies outside the UK to provide it with documents.

Acted for Which?, the Consumers' Association, intervening in this Supreme Court case regarding authorised push payment fraud.

Led the counsel team successfully defending the Secretary of State for the Environment, Food and Rural Affairs in a case concerning trade in endangered species.

Tristan led the counsel team for Ofcom in successfully defending a wide-ranging challenge regarding Radio One Dance, a new BBC online radio stream.

Tristan acted for the CMA defending Meta's judicial review of the CMA's decision to prohibit Meta's acquisition of Giphy. The case raises important questions regarding the assessment of potential competition.

Tristan acted as part of the team for British Sugar in this important case about EU state aid law as applied under the Northern Ireland Protocol; and about subsidies under the EU/UK Trade and Cooperation Agreement. 

Tristan was Advocate to the Court of Appeal in this wide-ranging decision regarding the courts' power to make injunctions against Persons Unknown.

Tristan acted for Dr Bell, a senior doctor, intervening in this high profile Court of Appeal decision concerning the circumstances in which children may consent to receive puberty-blocking drugs. 

Junior counsel for the Secretary of State in a challenge to the lawfulness, under retained EU law, of the so-called "immigration exemption" to the Data Protection Act.

Junior counsel in judicial review proceedings brought by a higher education provider in relation to the OfS's refusal to register it under the new regulatory regime under the Higher Education and Research Act 2017. The case was the first challenge to the OfS and raised issues of lawful delegation, the duty to consult, the public sector equality duty, A1P1, discrimination under Article 14 ECHR and proportionality.

High Court claim for Francovich damages arising out of the Secretary of State's failure to regulate medicines in accordance with the Medicinal Products Directive. 

Tristan acted for the PSA Executive in what the PSA has called a “landmark case” against a provider offering a platform for premium rate services such as games and adult content. The PSA Tribunal found that Veoo knowingly failed in its due diligence obligations, failing to take adequate steps to ensure that consumers had opted in to the services provided by those companies using its platform. The Tribunal imposed an unprecedented £600,000 fine and prohibited Veoo from providing premium rate services for two years.

Judicial review regarding the test to be applied by the ASA when deciding whether an advertisement is misleading.  The advertisements in question concern fibre broadband.

Represented Westminster City Council obtaining an interim injunction which prevented Transport for London from commencing works on a cycle superhighway.  Tristan was also junior counsel in the subsequent judicial review ([2018] EWHC 2402 (Admin)).

Tristan represented the Claimant in a five-day human rights damages action for alleged breaches in failing to recognise that the Claimant was a potential victim of human trafficking, and for failing to take steps to protect him.

Acted for the Claimant in obtaining interim injunction in respect of alleged abuse of dominance in cutting off supply of data.

Tristan led the team for Spreadex bringing a judicial review of a CMA merger decision. The decision was quashed and remitted and is currently under re-consideration.

Tristan led the JD Sports team defending claim for damages and injunction. (Settled 2025)

Tristan acted as part of the CMA's team in the 'Hydrocortisone' proceedings (concerning an unlawful agreement in the pharmaceutical sector) before the Competition Appeal Tribunal and the Court of Appeal.

Tristan led Primark's team in the interchange proceedings (competition damages claims against Mastercard and Visa) over several years prior to settlement in 2024.

Tristan led a team of six barristers in a six-week trial for the CMA, against five teams of opposing counsel, in a case concerning an alleged agreement regarding prochlorperazine.

Tristan acted for the CMA defending a judicial review concerning the CMA's power to require companies outside the UK to provide it with documents.

Tristan acted for Betgenius in defending a standalone competition claim regarding sports betting data. The case settled early in the trial. 

Tristan led the proposed class representative's application for a collective proceedings order against Google. The collective proceedings are currently ongoing.

Tristan acted for the CMA defending Meta's judicial review of the CMA's decision to prohibit Meta's acquisition of Giphy. The case raises important questions regarding the assessment of potential competition.

Tristan acted as part of the team for British Sugar in this important case about EU state aid law as applied under the Northern Ireland Protocol; and about subsidies under the EU/UK Trade and Cooperation Agreement. 

Junior counsel for the CMA in this challenge brought by Sabre Corporation for review under section 120 of the Enterprise Act 2002 of the CMA's decision preventing a merger between two companies active in the provision of IT solutions to airlines.  The case raises issues relating to the jurisdiction of the CMA in respect of foreign companies.

Junior counsel for the CMA in cartel penalty appeal raising important questions about the scope and proper application of the Authority's powers.

The case is brought on behalf of 46.2 million consumers, for losses running to several billion pounds. It is the first application for certification under the new collective action regime to have reached the Supreme Court. The Supreme Court rejected Mastercard’s appeal. Tristan acted for the intervener, Which?.  

Competition Appeal Tribunal decision regarding whether an additional party in a cartel damages claim is entitled to sue the claimants for a negative declaration.

Decision on applicable law in multi-national damages litigation.

Represented the Claimant in applications for an injunction and in preliminary issue trial on the question of whether the Defendant is an undertaking for the purpose of section 18 of the Competition Act 1998.

Tristan led the counsel team for Ofcom in successfully defending a wide-ranging challenge regarding Radio One Dance, a new BBC online radio stream.

Tristan acted for the PSA Executive in what the PSA has called a “landmark case” against a provider offering a platform for premium rate services such as games and adult content. The PSA Tribunal found that Veoo knowingly failed in its due diligence obligations, failing to take adequate steps to ensure that consumers had opted in to the services provided by those companies using its platform. The Tribunal imposed an unprecedented £600,000 fine and prohibited Veoo from providing premium rate services for two years.

Judicial review regarding the test to be applied by the ASA when deciding whether an advertisement is misleading.  The advertisements in question concern fibre broadband.

Representing Vodafone in proceedings regarding the “5G” spectrum auction.

Junior counsel to Ofcom in challenges to its Business Connectivity Market Review.

Junior counsel to the Altnets in appeals to the CAT relating to BT’s charges for Ethernet services.

Counsel for Hutchison 3G in a challenge to Ofcom's decision on spectrum licence fees.

Junior counsel to Ofcom in the ‘number porting’ appeal.

Junior counsel to Ofcom in the ‘VULA margin’ appeals.

Junior counsel for the interveners in appeals to the CAT and the Court of Appeal relating to BT’s charges for partial private circuits.

Tristan is acting for the Claimant in this case concerning the Part-Time Workers Regulations: the meaning of "less favourable treatment" and the correct approach to causation in establishing discrimination on grounds of part-time status. (Currently under appeal to the Supreme Court).

Tristan acted for the claimant in this important case concerning the obligations on an employer to consult fairly in a redundancy situation. The case considers the nature of the required consultation when there is individual consultation but no formal collective consultation.

Decision regarding the doctrine of state immunity in an employment context, and in particular its application to United States military bases in the United Kingdom.

Tristan represented the Appellant in this EAT appeal regarding the correct approach to an application to add an individual respondent to an employment claim after expiry of limitation.

Tristan represented the Claimant in the EAT appeal concerning the steps which a Tribunal is obliged to make to adjust the pre-trial process to enable a disabled litigant fully and fairly to participate in the proceedings. 

Tristan represented the Claimant in this EAT appeal concerning out of time amendments to pleadings. 

Tristan represented the Appellant in the Court of Appeal in an important decision regarding the meaning of a "provision, criterion or practice" in discrimination law, and the extent to which a one-off act may qualify.

Tristan represented the Appellant in the Employment Appeal Tribunal in a case concerning the treatment of medical evidence in an application to extend time for bringing a claim.

Tristan represented the Appellant in a case before the Employment Appeal Tribunal concerning the scope of the 'reasonable adjustments' duty.  The EAT held that being less efficient than non-disabled persons may constitute a relevant disadvantage within the Equality Act 2010, and that reasonable adjustments may include adjustments to make the disabled person more efficient.

EAT decision regarding the threshold for striking out a claim.

Tristan acted in two appeals before the Employment Appeal Tribunal concerning victimisation discrimination and the Police Conduct Regulations.

Represented the claimant in landmark Court of Appeal case concerning damages for stress at work in a discrimination context.