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Owain Thomas QC

Call:  1995 
QC: 2016


Owain Thomas QC has a broad practice with an emphasis on the areas of professional negligence, professional discipline, public law (in particular relating to healthcare), and taxation.

He has wide experience acting for both Claimants and Defendants (NHS and MoD) in clinical negligence, particularly high value claims resulting from birth injury or other catastrophic injuries. He has experience of a wide variety public law challenges against Mental Health Trusts in the Administrative Court and emergency injunctions and best interests cases in the Family Division.  He regularly appears for public authorities (hospitals, mental health Trusts and prisons) in complex inquests.

Owain has considerable experience in all areas of professional regulation and regularly appears on behalf of doctors, dentists and other professionals before the GMC, GDC etc.

He has represented the Commissioners of Customs and Excise in hundreds of cases in the domestic courts (in the Tribunal, the High Court and the Court of Appeal) and the European Court of Justice. His experience includes advisory work as well as advocacy in all areas of indirect taxation. 

He also has particular experience in the field of customs duties, goods classification, anti-dumping duty and landfill tax.

He undertakes a wide range of public law challenges particularly in the field of healthcare and tax litigation.

He is a member of the Professional Negligence Association, the Personal Injury Bar Association and the Administrative Law Bar Association.


In Clinical Negligence, Owain Thomas

"He is super-bright and his attention to detail is incredible." "His ability to distil the key issues in a claim from a variety of complicated sources at lightning speed never fails to impress." (Chambers and Partners 2017)
“takes a very detailed approach to cases.  He is also very client-friendly and very good in conferences.  He has the skills and experience to juggle between different medical injuries” (Chambers and Partners 2016)
“was brilliant and completely on top of the medicine” (Chambers and Partners 2015)
has a sharp legal mind, and is extremely approachable and knowledgeable. He is always courteous and helpful, particularly with clients." (Chambers and Partners 2014)
acted "brilliantly" and "fantastically well." "Bright and conscientious," he is a man with "a real eye for detail on the most intricate cases" (Chambers and Partners 2013)
has ‘excellent cross-examination skills (Legal 500 2012)
is a favourite of many of the solicitors that researchers spoke to. He "can quickly see whether a case is worth fighting, reassures clients" and is always "calm, considered and hard-working (Chambers and Partners 2012)
is described by sources as a "rising star who is competent on all fronts." (Chambers and Partners 2010)
is an “imaginative, dependable and very bright” junior known for “going the extra mile” (Chambers and Partners 2009).
"stood out as being amongst the market's leading juniors" (Legal 500, 2007).

In Professional Discipline, Owain

"is very good on his feet, he has excellent instincts when it comes to hearings. He's decisive and a wonderful strategist, even when under pressure." "He is reliably calm and considered during complex and lengthy cases." (Chambers and Partners 2017)
“is a delightful and able guy.”  (Chambers and Partners 2016)
“is intelligent and applies his mind to the facts and law in equal measure.” (Chambers and Partners 2015)
"is bright and conscientious, meets deadlines and is an all-round good advocate." (Chambers and Partners 2014)
is increasingly seen as a go-to junior for defending members of the medical profession, and is frequently instructed by the MDU and north of the border by the MDDUS. Those who encounter this "extremely intelligent" advocate are impressed by his diligence and his "eye for detail on the most intricate cases." (Chambers and Partners 2013)
is rapidly making a name for himself on the medical side of professional discipline, and has appeared in a number of important matters in recent years (Chambers and Partners 2012)

In Indirect Tax, Owain –

is “Very bright and knowledgeable on VAT.”  “A delight to work with.” (Chambers and Partners 2016)
“is a big hitter.  He is tenacious and really stands up for his client.  Technically excellent and very diligent.  He always gives you a good fight.” (Chambers and Partners 2015)
is "A very able barrister, who is very practical and very hard-working." (Chambers and Partners 2014)
notched up some impressive wins in indirect tax cases. "Clear in his advice and highly persuasive in court," he has frequently been seen in the European Court of Appeal.  (Chambers and Partners 2013)
is very good indeed and has done an excellent job on some big cases (Chambers and Partners 2012)
has developed a flourishing practice in the specialist area of customs classifications. "Diligent, knowledgeable and resourceful," he is one of the few experts in this area and is considered a fine advocate.  (Chambers and Partners 2010)
is recognised as a leading junior for his “thriving VAT practice” and “often prevailing over silks” (Chambers and Partners 2009).

In Inquests and Public Inquiries, Owain -

“He's great, incredibly clever and gets amazing results. He gets right to the heart of problems, is very insightful and offers good legal analysis.” “He is super bright and his attention to detail is incredible.” “He gives very well thought out, honest views of cases and grasps the medical facts with ease.” (Chambers and Partners 2017)
“is very impressive on his feet." (Chambers and Partners 2016)
“has a very sharp mind, is terrier-like on the detail and has always achieved a very good outcome for clients”  (Chambers and Partners 2015)


BA (Hons); BCL (Class 1)


Chapter on Taxable Transactions in “Value Added Tax, Commentary and Analysis” (Looseleaf) with Philippa Whipple (Sweet & Maxwell 2009)

Chapter on Waste in “Burnett Hall on Environmental Law”, Second Edition, with David Hart QC and Rachel Marcus (Sweet & Maxwell 2008)

Clinical Practitioners in “Professional Negligence and Liability” (Looseleaf) with Stephen Miller QC and Paul Rees QC (LLP 2000-2007)

Chapter on Sources of Human Rights Law in "Human Rights and the Common Law" Havers & English Ed. (Hart Publishing 2000)


Junior Counsel to the Crown 2008 (Attorney General's A Panel)
Junior Counsel to the Crown 2003 (Attorney General's B Panel)
Junior Counsel to the Crown 2001 (Attorney General's C Panel)
Lay Member of St Thomas' Hospital Local Research Ethics Committee 2004
School Governor Herbert Morrison Primary School 1999

Significant cases include the following

Significant recent cases

Please click on the printable version of the CV for a more detailed list

HMRC v Pendragon [2015] UKSC 37

Mercedes Benz v HMRC  [2015] EWCA Civ 1211

Volkswagen Financial Services Ltd v HMRC [2015] EWCA Civ 876

Cooneen Watts –v- HMRC [2015] EWCA Civ 1261 (end use relief and tariff classification)

Interfish Ltd v HMRC [2014] EWCA Civ 876

Subone Limited v HMRC [2014] EWCA Civ 773

Airtours c HMRC [2014] EWCA Civ 1033

CJEU Case C-183/13 Banco Mais, SA (2014)

CJEU Cases C 605/12 Welmory (2014)

R (Gibson) v GMC (2014)

R (Teue) v Health Education England (2014)

R (MS) v FTT (CICA) (2014)

Mercedes Benz Financial Services Ltd v HMRC [2014] UKUT 200 (TCC)

Cooneen Watts v Stone Ltd v HMRC [2014] UKUT 31 (TCC)

Subone Ltd v HMRC [2014] EWCA Civ 773

Interfish Ltd v HMRC [2014] EWCA Civ 876

Pendragon v HMRC [2013] EWCA Civ 868

Marco Trading v HMRC [2013] UKUT 0450 (TCC)

BAA Limited -v- HMRC [2013] EWCA Civ 112

Dr N v Warrington PCT [2012] UKUT 179 (AAC)

R(Hutton) –v- First Tier Tribunal and CICA [2012] EWCA Civ 806

Volkswagen Financial Services Ltd v HMRC [2012] UKUT 394 (TCC)

R (ota Modaresi) v Secretary of State for Health and others [2011] EWCA Civ 1359

GMC v Dr Wakefield and Others (2007 – 2010) -Junior Counsel for the GMC in the longest ever FTP hearing concerning research misconduct relating to the MMR vaccine. 

Case 653/11 Newey [2013] STC 2432

Joined Cases C-288/09 and 289/90 BSkyB -v- HMRC

Mid-Staffordshire NHS Foundation Trust Public Inquiry 2010-2012  Counsel for the NHSLA

Other information

VAT Registration No:  680 7971 93


Phone Clerk
020 7797 7500

Email Clerk


'One minute with...' Owain Thomas QC
Owain Thomas QC acted for the United Kingdom government in a recent preliminary ruling in the Court of Justice of the European Union regarding VAT
Owain Thomas QC wins VAT case for woodland charity
Supreme Court refers questions to the CJEU in Volkswagen Financial Services Ltd v Commissioners for HMRC