Gary Oliver
Senior Clerk
+44 (0) 207 822 7325
Tristan is widely recognised as a leading junior barrister across his core practice areas of public, regulatory and competition law. The legal directories recommend him for his clear and practical approach. He is regarded as the ‘go-to’ junior of choice for several regulatory clients, and is one of the Standing Counsel to the Competition and Markets Authority.
Tristan tends to act in large and complex cases, frequently leading a team of barristers and usually appearing against KCs. He recently (2023) led a team of six barristers in a six-week trial for the CMA, against five teams of opposing counsel.
Tristan also has a successful employment law practice, and he brings that additional expertise to cases raising issues which cut across different practice areas. He also has a longstanding interest in alternative dispute resolution, teaching and consulting on problem-solving negotiation skills.
Key recent quotes include:
Tristan’s practice covers the full range of public and regulatory law, from administrative law through to technical regulatory matters. The current edition of Chambers & Partners notes that he is sought after in “difficult administrative and public law disputes”.
Tristan has a particular reputation in cases raising complex technical or economic issues. Other recent work has included prison law, immigration, oil and gas licensing, pharmaceuticals, professional regulation, broadcasting, investigations, special educational needs and higher education law.
A selection of recent cases appears below.
“All of Tristan's work is really impressive. He's the barrister I would always wish to instruct for pretty much any regulatory issue, contentious or non-contentious.”
Chambers and Partners, 2023
“He is able to pick up any brief and master it in no time.”
Chambers and Partners, 2023
“He's a very good advocate; very good on his feet.”
Chambers and Partners, 2023
“He can absorb incredible amounts of detail and is excellent at witness handling.”
Chambers and Partners, 2022
“An understated, cool, calm and collected advocate. Sharp legal mind with persuasive drafting abilities. A go-to public law junior.”
Legal 500, 2022
“Really practical and an excellent advocate; he turns his hand to new things very easily.”
Chambers and Partners, 2021
“A great advocate - clear, knowledgeable and persuasive.”
Chambers and Partners, 2021
“A polite but deadly cross-examiner.”
Legal 500, 2021
“Makes very complex cases easy to understand, and helps the Tribunal get directly to the key issues in the case.”
Legal 500, 2021
“Bright, engaging and thorough. One of those we would always look to instruct.”
Chambers and Partners, 2020
“Responsive and quick-thinking. He gave a very focused submission.”
Chambers and Partners, 2020
“He is very practical and easy to work with and turns matters around quickly.”
Chambers and Partners, 2020
“Very bright and persuasive, he gets the context.”
Chambers and Partners, 2019
“Excellent legal analysis and written work.”
Chambers and Partners, 2018
“He is able to understand and present very complex data to the court in an accessible way.”
Chambers and Partners, 2018
“Brilliant competition and human rights junior.”
Legal 500, 2018
“Very impressive. Sharp, clever and a clear advocacy style.”
Chambers and Partners, 2017
“He is intelligent, hard-working and his advice is thorough, reflecting that he has diligently perused all of the papers down to the minute details.”
Chambers and Partners, 2016
“He works very effectively under great pressure, he is a good analyst and draftsman.”
Chambers and Partners, 2016
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 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.
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 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.
Tristan was Advocate to the Court of Appeal in this wide-ranging decision regarding the courts' power to make injunctions against Persons Unknown.
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.
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.
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?.
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.
Tristan represented the Claimant in an Upper Tribunal appeal regarding the law concerning the deportation of a foreign criminal.
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)).
Representing Vodafone in proceedings regarding the “5G” spectrum auction.
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.
Junior counsel to Ofcom in challenges to its Business Connectivity Market Review.
Counsel for Hutchison 3G in a challenge to Ofcom's decision on spectrum licence fees.
Junior counsel to the Claimants in a judicial review establishing that the Secretary of State must reconsider whether products which contain glucosamine are medicinal products.
Represented the Secretary of State in a judicial review of a decision that deception had been used in an immigration application.
Counsel for Ms Jeffrey in a test case appeal on the retrospective nature of the Jobseekers (Back to Work Schemes) Act 2013.
Part of the interveners team in a case concerning constitutional protection of the rights of homosexuals.
Junior counsel to the claimants in a judicial review of changes to the provision of criminal legal aid.
Represented the respondent in an appeal to the Upper Tribunal concerning the entitlement to Employment and Support Allowance of women in domestic violence refuges.
Junior counsel to the respondent in claim for compensation under POCA (now settled).
Acted for the respondent in challenge to prisoner voting legislation.
Acted for the respondent in a judicial review of a decision relating to a prisoner’s sentence.
Junior counsel for the claimant in a challenge to the defendant’s decision not to grant Renewables Obligation Certificates in respect of certain electricity generating stations.
Junior counsel for the Claimant in a habeas corpus application on behalf of a man detained in Bagram prison.
Junior counsel to the Press Standards Board of Finance Ltd in relation to the Leveson Inquiry’s consideration of the appropriate framework for media regulation, including competition issues relating to self-regulation.
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 as part of a team for the Office for Students in this first judicial review brought against the new regulator. The case raised questions regarding the new statutory framework for the regulation of higher education, and issues relating to the education provider's A1P1 property rights.
Tristan is a leading EU and competition junior. He is one of the Standing Counsel to the Competition and Markets Authority.
Tristan has appeared in many of the leading competition damages cases, including those concerning infringements in interchange fees, air cargo, bearings, rubber, and copper tubes. In addition to the cases listed below, he is currently acting for a large multinational group of claimants in the trucks litigation, and for one of the defendant banks in the forex claims.
In collective proceedings, Tristan acted for the claimant in the first application for a Collective Proceedings Order. He represented Which? in its intervention in the Supreme Court in Merricks concerning the new collective proceedings regime. He recently acted for the class representative obtaining a CPO against Google, and is currently instructed in several other collective claims.
Tristan has also appeared in some of the main challenges to regulatory competition decisions, including in antitrust and merger cases. In the merger space, his experience includes acting for Ryanair in its challenges to the CMA, as well as more recently for the CMA in the two high-profile technology sector merger challenges in 2020 (the CMA's Sabre/Farelogix decision) and 2022 (Facebook/Giphy). In addition to the cases listed below, he has recently acted in two other Chapter I and Chapter II cases (liothyronine and prochlorperazine).
Tristan also has state aid and subsidy experience. He acted as lead counsel for the claimants in the 2019 state aid challenge to the capacity market. In 2022 he was been part of the team acting for British Sugar in a challenge to import tariff rules.
A selection of Tristan's recent cases appears below.
“Tristan is one of the standouts and a star of the future. He's got particular expertise in class action and large-scale multiparty cases. He's very easy to deal with and responsive and hard-working.”
Chambers and Partners, 2023
“He is pragmatic. He just does not miss anything in a case: everything is dealt with very thoroughly.”
Chambers and Partners, 2022
“Tristan is a star junior – he is tremendously clear thinking and excellent both in court on paper.”
Legal 500, 2022
“Tristan is extremely highly sought after and very experienced.”
Chambers and Partners, 2021
“Very approachable, great to work with and humble.”
Legal 500, 2021
“An extremely competent advocate and more than a match for many silks in the competition litigation world.”
Legal 500, 2021
“A polite but deadly cross-examiner able to be very thorough without tripping into pedantry.”
Legal 500, 2021
“Really eloquent and persuasive, he is a clever, articulate and calm advocate.”
Chambers and Partners, 2020
“He gets stuck in and is very thorough and diplomatic. It is always fine to put him in front of clients because he has always thought about all of the issues and is well prepared.”
Chambers and Partners, 2020
“A very good team player, who is very bright but practical.”
Chambers and Partners, 2019
“He focuses on the issues that matter and does very high-quality work.”
Chambers and Partners, 2018
“Brilliant competition and human rights junior.”
Legal 500, 2018
“Cool, calm and collected.”
Legal 500, 2018
“Very approachable and easy to work with.”
Legal 500, 2018
“He is brilliant to work with. He has an excellent grasp of the detail but, critically, also adopts a very sound and commercial approach”
Chambers and Partners, 2017
“He is very mature and confident for his years and will undoubtedly develop into one of the leaders of the Competition Bar in future years.”
Chambers and Partners, 2016
“A very convincing advocate with an excellent grasp of the detail”
Legal 500, 2016
“Very knowledgeable and assured for his level of call.”
Legal 500, 2015
Acted for Which?, the Consumers' Association, intervening in this Supreme Court case regarding authorised push payment fraud.
Acted for the CMA defending decision regarding abusive pricing on the pharmaceutical product Liothyronine.
Tristan acted for Betgenius in defending a standalone competition claim regarding sports betting data. The case settled early in the trial.
Case concerning without prejudice privilege where communications relate partly to privileged issues and partly to wider commercial issues.
Tristan acted for the proposed class representative in her application for a collective proceedings order against Google.
Tristan acted for the CMA in this challenge by Meta against 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 cartel penalty appeal raising important questions about the scope and proper application of the Authority's powers.
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.
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?.
High Court damages claim, concerning the question of whether the Medicinal Products Directive, which imposes regulatory and supervisory obligations on Member States, entails the grant of rights to individuals so as to provide the necessary foundation for Francovich damages.
Competition Appeal Tribunal decision regarding whether an additional party in a cartel damages claim is entitled to sue the claimants for a negative declaration.
Tristan is currently junior counsel to several groups of claimants in a damages claim arising out of the EU-wide cartel in trucks.
Decision on applicable law in multi-national damages litigation.
Junior counsel to the claimants in cartel damages action arising out of the European Commission's Bearings decision (CAT). [settled]
Junior counsel to the claimants in damages claims relating to the setting of interchange fees (Chancery division and CAT). Reported decisions in the case relate to jurisdiction and relation back.
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.
Junior counsel for the proposed class representative in the first proposed opt-out class action in the UK concerning infringements of competition law in the sale of mobility scooters.
Junior counsel to one of the defendants, Polar Air Cargo LLC, in cartel damages action (Chancery division).
Junior counsel for the claimants in the first cartel follow-on damages to reach trial (prior to settlement).
Junior counsel to the applicant in a challenge to the CC’s decision to order divestiture of Ryanair’s holding in Aer Lingus.
Represented the claimants in follow-on damages claims in the High Court relating to copper tubes cartel (prior to settlement).
Junior counsel to Ryanair in proceedings relating to its acquisition of a minority stake in Aer Lingus.
Junior counsel to the Press Standards Board of Finance Ltd in relation to the Leveson Inquiry’s consideration of the appropriate framework for media regulation, including competition issues relating to self-regulation.
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 is recognised as a leading junior in telecoms law, which brings together his EU, regulatory and competition expertise. He has appeared in many of the main cases over the last decade, and is frequently instructed by Ofcom as well as by industry. A selection of recent cases appears below.
“He is very easy to work with and provides intelligent, practical advice.”
Chambers and Partners, 2023
“He is very effective.”
Chambers and Partners, 2023
“He is a very clever person, a good advocate, and someone who is very pleasant to work with.”
Chambers and Partners, 2021
“He pays meticulous attention to detail and is extremely clever.”
Legal 500, 2021
“A smooth character, who is responsive and quick-thinking.”
Chambers and Partners, 2020
“He is a hard-working, bright and very able junior.”
Chambers and Partners, 2020
“He pays meticulous attention to detail and is extremely clever.”
Legal 500, 2019
“He knows the telecoms industry really well, is very sharp-witted and his drafting is excellent.”
Chambers and Partners, 2019
“He has a deft touch when it comes to setting expectations and making the client feel comfortable with how a case is progressing.”
Chambers and Partners, 2019
“A dedicated and conscientious junior with great writing skills and a wealth of experience of acting for telecoms regulatory bodies.”
Chambers and Partners, 2018
“He is an excellent junior for telecoms regulatory disputes.”
Chambers and Partners, 2018
“‘Clearly a star in the making.’”
Legal 500, 2018
“A very practical, hard-working junior who handles clients extremely well”
Chambers and Partners, 2017
“A highly competent and insightful advocate for regulators”
Legal 500, 2016
“I can't speak highly enough of him as a junior - he's extremely hard-working, very bright and very, very good with clients.”
Chambers and Partners, 2016
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 acts in a wide range of cases raising civil liberties and human rights issues. His recent advocacy work has included acting for the claimant in a five-day human trafficking damages claim in the High Court, and acting for a claimant in the Court of Appeal on a test case regarding Jobseekers’ Back to Work Schemes.
A selection of recent cases appears below.
“Brilliant competition and human rights junior.”
Legal 500, 2018
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.
Tristan was Advocate to the Court of Appeal in this wide-ranging decision regarding the courts' power to make injunctions against Persons Unknown.
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.
Counsel for Ms Jeffrey in a test case appeal on the retrospective nature of the Jobseekers (Back to Work Schemes) Act 2013.
Part of the interveners team in a case concerning constitutional protection of the rights of homosexuals.
Represented the respondent in an appeal to the Upper Tribunal concerning the entitlement to Employment and Support Allowance of women in domestic violence refuges.
Acted for the respondent in challenge to prisoner voting legislation.
Acted for the respondent in a judicial review of a decision relating to a prisoner’s sentence.
Junior counsel for the claimant in a challenge to the defendant’s decision not to grant Renewables Obligation Certificates in respect of certain electricity generating stations.
Junior counsel for the Claimant in a habeas corpus application on behalf of a man detained in Bagram prison.
Tristan acted as part of a team for the Office for Students in this first judicial review brought against the new regulator. The case raised questions regarding the new statutory framework for the regulation of higher education, and issues relating to the education provider's A1P1 property rights.
Tristan has experience of a wide range of employment disputes, covering Employment Tribunal and High Court cases.
Tristan has particular expertise in equal pay and the Equality Act. He regularly appears in the Employment Appeal Tribunal, and he acted as sole counsel for the successful claimant in the leading Court of Appeal case on discrimination causing stress at work. He has also acted in several high profile disability discrimination claims.
Tristan is currently acting for the claimants in two large sets of group equal pay claims in the retail sector, one against Morrisons and one against Boots.
A selection of recent cases appears below.
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 Claimant in EAT case raising issues of disability discrimination and victimisation.
Represented the claimant in landmark Court of Appeal case concerning damages for stress at work in a discrimination context.
Junior counsel for the claimant (with Dinah Rose QC) in a test case on the lawfulness of the arrangements regarding part-time police inspectors’ pay.
MA Hons (Cantab) Starred First Class; Masters in Public Administration (Harvard) (Kennedy Scholar); Diploma in Law (City) Distinction
As a student and young barrister, Tristan won several scholarships and prizes. Those included the James Hunt Advocacy Trophy, a prize for the best advocacy among Gray’s Inn students.
Tristan teaches legal negotiation skills. For several years, he was an Adjunct Professor of Law at Georgetown University, where he taught an intensive Legal Negotiation Seminar. He has taught and consulted on negotiations for organisations including the Norwegian Bar Association, CocaCola, Wyeth Pharmaceuticals, and Merrill Lynch. In 2006, he was named Young ADR Professional of the Year by the ADR Group.
Before training as a barrister Tristan worked as a journalist for an international news agency. Prior to that, he was President of Cambridge University Students’ Union.
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