Tom is a highly versatile lawyer whose practice straddles public/EU law, competition/regulatory law and commercial law, and who has achieved recognition as a leading practitioner in eleven different practice areas. Tom is noted for his innovative legal problem solving - drawing upon the many aspects of his practice - and his excellent advocacy. He is regularly instructed in highly complex cases spanning different areas of law, to lead large teams of counsel and solicitors.

In the public law field, Tom’s work has a strong emphasis on: commercial JR, particularly economic sectoral regulation (gas, electricity, water, telecoms) where Tom has acted for and against most of the sectoral regulators; pharmaceutical and life sciences regulation; sanctions work; civil liberties and national security issues; data protection and privacy; social security; medical regulation and discipline; and environmental cases. Tom is a noted expert on proportionality, the control of secondary legislation and on challenges to primary legislation, having obtained the first ever declaration of incompatibility by consent (Blood No.2) and the last EOC declaration to disapply primary legislation for incompatibility with EU law (Hughes).

In the competition field, Tom has appeared in many of the leading competition law damages cases (Provimi, Devenish), acting regularly for both Claimants and Defendants in follow and hybrid claims, as well as in standalone cases. Tom did the first CPO case and has been involved in numerous CPOs since for both Claimants and Defendants. Tom has particular expertise in the application of the competition rules in the context of sport, acting for both the regulated (clubs, players etc) and the regulators/leagues (RFU, Premier League, ECB) and in standalone disputes about sports data, promotion/relegation, financial fair play etc.

Tom’s commercial work has an emphasis on group litigation (most recently leading the various Dieselgate disputes, including the ground-breaking PanNox litigation), conflicts issues (most recently MV Prestige), economic torts (particularly market-facing disputes), privacy (e.g. ENRC v Gerrard) and restitution litigation (e.g. the ALFs litigation).

A unifying feature of all of Tom’s work is his noted expertise in EU law work in all hues, public, regulatory or commercial. Before Brexit, Tom appeared in many CJEU/GC cases, in areas ranging from sanctions, to competition and sport, trademarks, consumer law, pharmaceutical work , social security co-ordination to conflicts, data protection/privacy and to Brexit itself (Tom acted for HMG in the Wightman case). Tom appeared in the last two Article 267 TFEU references from the UK (DfCNI and MV Prestige).

Tom is recognised as a leading silk by latest editions of both the independent legal directories, Chambers & Partners (11 categories and a “Star of the Bar”), Legal 500 (5 categories). Key recent quotes include:

  • "Thomas de la Mare KC is an absolute star of the Bar and an exceptional advocate." - Chambers UK, 2025
  • “Tom is a top of the range advocate. Unrivalled depth of knowledge in his specialist areas, especially EU law, combined with an attractive, clear and persuasive advocacy style. He has the knack of making you think you would be crazy not to agree with him, even when he is wrong. Respected by the senior judiciary” – Legal 500, 2025

Previous comments include:

  • "He is legendary for his creative and lateral thinking. He comes up with winning ideas that others just don’t think of."- Legal 500, 2024
  • "Thomas is a powerhouse; he is incredibly impressive on his feet, and has an extraordinary capability to manage a complex case load effortlessly."- Chambers UK, 2024
  • "He is an excellent and engaging advocate."- Chambers UK, 2023
  • "He is very quick to see the key points and very practical. He is extremely articulate and forceful when putting across his points for the client."- Chambers UK, 2023
  • "Thomas de la Mare is a Premier League KC who always adds value."- Chambers UK, 2023
  • "Incredibly bright; he thinks of different perspectives and can pick up totally new areas of law in no time at all. He is otherworldly."- Chambers UK, 2023

Experience

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Public & Regulatory

There is a very considerable overlap between Tom’s public law, human rights and EU and environmental expertise. Clients seek Tom out, in particular, for his ability to provide comprehensive expert advice straddling these fields. Current comments (Chambers 2025):

  • "Thomas is brilliant, great in court and fights really hard. He is a very strategic thinker and gets through an insane amount of work."
  • "Thomas is incredible at getting to the heart of key issues and getting to persuasive arguments."
  • "He is an excellent advocate who has a very good manner both with clients and the court."
  • "Thomas de la Mare KC is very impressive in court."

Tom has expertise in a wide range of fields of commercial, technical and professional regulation and discipline, particularly where harmonized by EU law such as: pharmaceuticals, medicinal devices, foods and food supplements, pesticides and GMOs; financial services, legal services; medical services and qualifications; transport/aviation, broadcasting and advertising (see Media section below for further detail).

Tom’s EU public law practice is extremely broad (see further below for the commercial aspects of Tom’s EU practice). He regularly appeared for and against the UK in the CJEU/GC and in cases raising EU law points in domestic tribunals. The public law dimension to Tom’s EU practice embraces subjects as diverse as customs and duties control, social security co-ordination, immigration and asylum, discrimination, citizenship, free movement (goods, persons, services), the EU Charter.

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Civil Liberties & Human Rights

Tom’s civil liberties practice has a wide scope: terrorism, torture, unlawful detention, free speech, data protection and privacy, discrimination, property and fair hearings have featured particularly prominently in Tom’s recent work for a diverse range of individual, corporate and public clients. Tom was for many years a Special Advocate and involved as such in some of the highest profile cases (Belmarsh, Binyam Mohammed, Abu Doha); and recently has been involved in long-running and ground-breaking privacy litigation in the IPT against the security services (for Privacy International and Liberty). He has done a substantial number of national security control order, TPIM and JSA cases for Claimants, notably the Kamoka/LIFG litigation.

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Competition

Tom is a highly experienced and sought-after competition lawyer. Tom acted in the very earliest follow on damages claims and the first CPO and has acted for Claimants, Defendants, regulators and the regulated alike. He has an extensive practice ranging from pure commercial/competition work, through to regulatory competition work in fields like gas, electricity, water and telecoms regulation (areas that draw on his strengths in EU and public law work too). Recently Tom has been instructed on CPOs for both Claimants and Defendants (Riefa, Musical Instruments, Motor Finance), as well as in high profile standalone or hybrid litigation (FX, Trucks, Interchange, Sports Radar, Diesel)

He is a long-standing member of the CAT Users Group.

Tom was the Legal 500’s EU and Competition Silk of the Year in 2019 and is ranked Band 1 and 2 for Competition law in Legal 500 and Chambers & Partners respectively (“He is a leader in this area and really knows his stuff. He was one of the first barristers to really see the potential of group and class actions”).

“Pure” competition damages: Tom has acted in a large number of the most prominent competition damages claims since the Vitamins litigation in the mid-00s (in which Tom acted for the Defendants, Aventis, in Provimi, Devenish and other reported cases).

Since then, Tom has acted for Claimants in Air Cargo (Emerald), RoRo, Interchange (multiple parties and firms), Peugeot Bearings, Trucks, Diesel, among others. He has also worked for Defendants in the various vitamin cases (Aventis), LCDs (Toshiba in Nokia) on Power Cables (Nexans), the FX litigation (Goldman Sachs), sports data litigation (for Genius), football shirts litigation (for Newcastle).

Blended competition claims and competition consumer law: Tom is at the forefront of modern cases involving competition law issues blended with other private law claims. This was a particular characteristic of the two strands of the recent Genius litigation (which also involved database, confidentiality and unlawful means claims) and is a particular feature of the Diesel GLO claims against Mercedes, BMW and VW (given their participation in a technology suppression cartel). Tom’s particular interest in broadcasting, media, consumer law and data protection means he is well placed to advise and act on such issues where they interface (as they increasingly do, particularly in the digital space) with competition law, especially in abuse of dominance claims.

CPOs and “book built” claims: Tom has written extensively, advised, and acted in relation to CPOs, including in the Pride Mobility Scooters application (the first under the Act), including both follow on and standalone claims. Recently Tom has been instructed in the Riefa proceedings against Apple and Amazon; and by Defendants in the applications for CPOs in Musical Instruments and Motor Vehicle Finance. Tom was a member of the CAT Working Party on collective proceedings.

Competition & Sport: Tom is an acknowledged expert on the interface between competition law, common law, restraint of trade, and sport, in relation to issues such as salary caps (RFU, Scarlets, F1), financial fair play (RFU, competition law arbitrator in the QPR arbitration), player nationality requirements (ECB, RFU, F1), fixture and league sanctioning/breakaway competitions (Premier League) and regulation by dominant sports bodies (ECB, RFU). Tom is also well versed in the competition (and other) events relating to “Listed Events” (having acted in the GC/CJEU in the FIFA/UEFA cases) as well as the competition law issues in relating to sports broadcasting (e.g. Virgin complaint, Genius litigation).

Regulatory EU/competition work: Tom has undertaken work in all the main fields of sectoral regulation based on EU frameworks on both pure competition points and sectoral regulatory issues (such as systems access, price control etc), notably telecoms (both for and against Ofcom, including currently acting against Ofcom in the first exercise of its competition investigation powers), gas and electricity (for and against Ofgem and the NIAUR) and water (against Ofwat).

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EU Law

Tom is a highly experienced and much sought-after EU lawyer. He has an extensive practice ranging from EU regulatory (with its blend of public and competition law), commercial EU (such as financial services and conflicts) to diverse “pure public” EU work in areas such as pharmaceutical regulation, data protection and privacy, free movement cases, EU social security and EU fundamental rights and discrimination.

Tom is an acknowledged expert on both Brexit (in particular the operation of EUWA 2018, the Withdrawal Agreement, EUFRA 2020, the TCA and REULA) and (formerly) state liability claims.

Tom was the Legal 500’s EU and Competition Silk of the Year in 2019 and is ranked in Band 1 for EU Law (“Tom is pre-eminent in the field, entrusted by clients and plainly highly respected by the tribunals before whom he appears”) by both Legal 500 and Chambers & Partners.

State liability: Tom has acted on both sides of many EU state liability claims, including recently for a claimant class of persons affected by mistransposition of an EU Directive, and for the MIB in the Colley litigation (heard by the CA in January 2022). Such cases require a mix of public law expertise (is a breach ‘manifest and grave’?) and commercial litigation know-how (causation, quantum, market modelling) and have strong similarities with competition law “follow on” claims.

Brexit: Tom is one of the acknowledged experts on the UK’s Brexit arrangements, including all aspects of EUWA 2018 and EUFRA 2020 and the Withdrawal Agreement and TCA. Tom acted for the Public Law Project in the Miller2 litigation and for the UK in CJEU Grand Chamber hearing in Wightman. He frequently gives presentations on these topics, has advised extensively on them, and has been brought into litigation to advise specifically on these issues.

EU Fundamental Rights and Treaty rights cases: Tom has been involved in some of the most prominent recent cases involving EU Fundamental Rights and EU Treaty rights issues of recent years, including Lumsdon in the Supreme Court (the leading authority on EU proportionality), FACT (proportionality and free movement of goods in relation to the Ivory Act), Hughes (Pensions Act disapplied as incompatible with EU fundamental age discrimination rights), TfL (EU free movement and proportionality) the Privacy International Litigation (s.94 Telecommunications Act inconsistent with EU privacy law) and AT v. SSWP (CFREU and the Withdrawal Agreement).

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Environment

Tom practises extensively in environmental law. Through leading cases like Fish Legal (CJEU), Barr v Biffa (CA) and the Manchester Ship Canal case (SCt) Tom has built a leading practice in water and waste litigation and its interaction with private and public nuisance. Through the Dieselgate litigation Tom has added a deep understanding of air pollution regulation. And through regulatory work Tom has added expertise on renewables and their regulation, both in mainland GB and in the SEM/NI. Tom has also provided a wide range of regulators (e.g. OEP) and the regulated with advice on the operation and application of environmental legislation.

Client comments (Chambers & Partners, 2025) include:

"Thomas is my go-to silk for complex and high-stakes environmental matters. He is a hugely impressive and persuasive advocate, who quickly distils complex cases into cogent and compelling arguments."

Examples of Tom’s current and recent work in this area can be found below.

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Commercial

Given Tom’s strength in EU, conflicts of law and competition law, he is regularly in demand in commercial disputes intersecting with those areas, particularly in the burgeoning field of group litigation. Tom has regularly acted in commercial issues in the CJEU, THE Court of Appeal as well as the Commercial Court and Chancery Division. Beyond these areas Tom’s general commercial litigation practice spans a wide range of areas including: conspiracy and economic torts (especially using civilian unfair competition torts with English disclosure); civil fraud, particularly in a commercial employment context; confidential information and soft IP (trademarks, copyright); restraint of trade and restrictive covenants.

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Pharmaceuticals

Tom’s EU and public law expertise combine in regulatory pharma and life sciences work (PPPs, medical devices, food law, borderline products), which Tom has been doing since he first came to the Bar. He has extensive experience of pharmaceuticals litigation in the domestic Court, the CJEU and GC; and has acted in and advised extensively upon the post-Brexit landscape. Tom even acted for the EMA in its dispute with its landlord following its departure from the UK after Brexit. Examples of his current and recent work in this area can be found below.

Tom had acted on or advised in relation to cases raising issues under the centralized and decentralized procedure, the orphan drugs regulation, conditional marketing authorization, prescription incentive schemes, off-label prescribing, conditional MAs, the various post-Brexit MAs, reimbursement, drug pricing and cartels, parallel importing and associated IP issues. Tom has acted regularly for both generic and originator companies; and as part of a wider strategic team in parallel regulatory and IP/patent disputes. He is ranked Band 1 in Chambers & Partners, 2025, Life Sciences Regulatory, where client comments (Chambers & Partners, 2025) observe:

  • "He is an exceptionally clever lawyer."
  • "Tom is absolutely a first-class advocate with a rare combination of being an effective, brilliant advocate and also enormously clever."
  • "Thomas is a highly intelligent lawyer with a highly creative legal mind."
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Sport

Tom practises extensively in sports law and examples of his current and recent work in this area can be found below, and is particularly sought-after for advice on the application of competition law to sports regulation. He has acted for or advised most of the major SGBs (Premier League, EFL, ECB, RFU, LTA), for teams or athletes, for sponsors and in associated fields like sports data and broadcasting. Tom also has advised and acted regularly on issues connected with the policing of sports events.

Tom is ranked in Sport in both Chambers & Partners (Band 3) and Legal 500 (Band 2, “best in the business for competition law issues in sport”)

Tom has written (with Ravi Mehta) the Chapter in Lewis & Taylor on Sport on EU free movement rights.

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Media & Entertainment

Ever since pupillage with Ian Mill KC 30 years ago, Tom has pursued a practice in Media & Entertainment and Broadcasting litigation, embracing matters such as record company and recording agreement disputes, restraint of trade, film finance, collecting society disputes, broadcasting and advertising regulation and disputes. Tom also undertakes a wide range of related soft IP litigation, whether in copyright, trademarks, passing off and the like.

Tom’s human rights work, and its focus on data protection and privacy, surveillance and bulk data handling also proves invaluable from media and entertainment perspective, as Tom’s recent work in media list cases such as Gerrard v ENRC (on the interface between commercial surveillance and harassment) and Webster v HMRC attest.

With technological convergence such skills have also frequently proved invaluable in competition and sports disputes with broadcasting/entertainment dimensions, such as the live sports data litigation Tom conduced for Genius; or in advising on the Digital Markets, Competition and Consumers Act 2024.

Tom is regularly consulted for his expertise in advertising law, particularly EU law relating to consumer protection. He has regularly advised and acted for the OFT/CMA, the ASA, BCAP and other self-regulatory bodies, as well as private parties.

Tom is ranked as Band 2 (Chambers & Partners, 2025) with commentators stating:

  • "Thomas is incredibly accessible, incredibly engaged, hugely persuasive and incredibly resourceful too."
  • "He's a brilliant lawyer - very academic and very impressive."

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Telecommunications

Tom has been involved in a number of high profile telecommunications disputes (e.g. 3G and 4G Auctions, ALFs and associated restitution litigation), acting for, amongst others, O2, H3G, Vodafone, Virgin, 118 118, Lebara, Inmarsat, the MoD and Ofcom.

Tom has particular experience in relation to the national security issues that arise in a telecommunications context, including in relation to surveillance warrants, bulk data warrants and the operation of IPCO, having acted for Privacy International in its eight years of litigation with the security services (including in the CJEU); and latterly in the combined Liberty/Privacy case.

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Achievements

Education

BA (Oxon), 1st class; LLM (EUI)

Publications

  • Tom co-wrote three chapters in Lester & Pannick (ed), Human Rights Law & Practice (2nd ed).
  • Tom wrote the chapter, Remedies, in B. Lang (ed), Administrative Court: Practice & Procedure.
  • Tom wrote the chapter on Preliminary Rulings in Craig & de Burca, EU Law in Social and Political Context and rewrote the chapter in the 2nd edition with Catherine Donnelly.
  • Tom co-wrote (with Robert Howe QC) the original chapter on Confidential Information in Goulding (ed), Employee Competition: Covenants, Confidentiality and Garden Leave.
  • Tom co-wrote (with Ravi Mehta) the chapter on Sport and free movement under EU law in the third edition of Lewis and Taylor’s Sport: Law and Practice.
  • Tom is a regular contributor to publications such as Judicial Review, on a wide range of public law topics.
  • Tom is a regular speaker at seminars organised by bodies like PLP, Liberty, JUSTICE, ALBA and BEG, on topics of EU law, Brexit, competition law and reform, group litigation, conflicts, fraud and other commercial topics.

Appointments

  • Chairman of the Bar European Group (2011-2013)
  • Former Committee Member of BEG and ALBA
  • Former Member of Bar Pro Bono board
  • Bencher of Middle Temple

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