Barrister David O'Mahony

David O'Mahony

Year of call: 2000  


“A dream to work with, he combines his first-rate legal intellect with real common sense and is always methodical, organized and responsive with his advice.”



What the directories say:

 “A very bright man who has great depth of knowledge of the way civil litigation interplays with criminal law.”

“He is very intelligent, has a good grasp of the detail in a case and is very hard working.”

“Offers first-rate advice and can be trusted with the most difficult cases.”

Chambers & Partners Guide to the UK Bar and Chambers Global editions 2013 – 2018

David O’Mahony specialises in cases in which international issues arise. He has particular experience in offshore issues. His practice has ranged across this field of the law being instructed in cases involving money laundering and criminal fraud, civil and commercial law (particularly fraud), arbitration (both commercial and investment arbitration), domestic and international financial regulation and international crime. He advises on public and private international law and international criminal law.

He has deep knowledge of the law of bribery and corruption. He has acted for and against companies as well as individuals in corruption cases. He has also acted in parallel civil and criminal proceedings He has acted for a number of developing world governments in corruption investigations and negotiated a settlement agreement with one of the world’s largest multi nationals.

David also advises on sanctions related issues (including in an offshore context). He has advised on a number of the sanctions regimes including in relation to Russia/Ukraine and Iran. He has advised on both the government and corporate side of these issues.

David has been instructed in cases in the UK, Africa, the Caribbean, Central Asia, the Channel Islands (particularly Jersey), the Gulf, the Indian sub – continent and South East Asia. He has been called to the bar in Australia, the DIFC courts and the TCI. He is on the list of counsel at the International Criminal Court and the Special Tribunal for Lebanon in the Hague, and has acted successfully for the UK government in the European Court of Human Rights. He has appeared as junior counsel in commission hearings in the Indian courts and in the Privy Council. He is on the Serious Fraud Office ‘A’ Panel for Proceeds of Crime Act cases.

He has worked with Swiss investigating magistrates and the USDOJ as well as public authorities in the developing world.

David has degrees from Cambridge University and the University of Queensland, and tutored Public Law at the London School of Economics and Political Science (‘LSE’). He attended the Hague Academy of International Law Advanced Course in International Criminal Law and the European University Institute Human Rights Law summer school.


David’s professional memberships include the International Bar Association and Chatham House.

David is also co-author of a chapter on civil fraud and the cross over issues between civil and criminal fraud proceedings in Butterworths Fraud Practice.

He has given talks for the United Nations Office on Drugs and Crime (UNODC) in Turkmenistan and Kazakhstan and was instructed by the UNDP to assist in its review of the draft Criminal Procedure Act for Sierra Leone.


  • First Trust Management AG v. Attorney General [2018] JRC 64 the Royal Court of Jersey upheld a US$ 23 million freezing order on behalf of the USDOJ and gave important guidance on the interaction between offshore trust and company structures and criminal orders.
  • United States v. Doraville [2017] JCA 029, [2017] JRC 19 and [2016] JRC 128 Acting for the United States of America and the Attorney General for Jersey in parallel proceedings to enforce a US$ 300 million corruption forfeiture order and other relief
  • Viscount v. Arthur and Others [2017] JCA 52, acting for Viscount of Jersey in the Jersey Court of Appeal concerning whether she has duties akin to those of a trustee;
  • WTHK and Anor v. UBS Trustees (Jersey) Limited [2016] JRC 99 and 113, Jersey trust proceedings concerning a € 990 million fund;
  • Bhojwani v. United Kingdom application number 49964/11 21st June 2016. Acted successfully for the UK government in the ECtHR in US$ 43 million corruption money laundering case;
  • Dransfield v. Information Commissioner [2015] 1 WLR 5316. Case in which the Court of Appeal gave guidance on the meaning of a ‘vexatious request’ in the FOI Act;
  • Minister of Treasury and Resources v. Harcourt and Anor 2014 (2) JLR 353. Acted for the Finance Minister of Jersey in a £ 100 million claim for inducing breach of contract.
  • R v Batchelor [2013] EWCA Crim 2638.
  • R v. Venclovas (instructed to deal with international issues) first case to be prosecuted under section 4 Suppression of Terrorism Act 1978;
  • A series of multi – million dollar claims under the DIFC – LCIA rules and in associated injunction proceedings in the DIFC Court.
  • Attorney General for the Turks and Caicos Islands v Oceanpoint Developments & Ors: Acting for the defendants in a US$ 14 million claim in the Turks and Caicos Islands courts to recover the proceeds of corruption.
  • Advising a listed mining company in relation to its Mongolian subsidiaries.
  • Junior counsel for Eric Illsley MP in one of the MPs expenses cases.
    Acting for the Attorney General for Jersey in a series of international corruption money
  • Laundering cases including: Attorney General v Bhojwani [2009] JCA 115A (in the Jersey Royal Court, Court of Appeal and Privy Council).
  • Acting for the National Accountability Bureau of Pakistan (‘NAB’) in a series of civil and criminal corruption cases including ‘Bhutto’.
  • Acting for the Kenyan Anti-Corruption Commission (‘KACC’) in a series of corruption cases.
    Acting for a hedge fund manager in a dispute over the US$ 97 million proceeds of a hedge fund: UCC v Bender [2006] JLR 269.

How to get in touch

For more information please contact our clerks by calling +44 (0) 20 7242 3555 or by email.


Privacy Notice

David is committed to protecting and respecting the privacy of individuals. In order to provide legal services, including advice and representation services, David needs to process personal data. This will include client’s personal data and the personal data of others who feature in the course of any matter upon which he is instructed.

David will process personal data in accordance with her Privacy Policy.

Please click here to see how David will, absent any other arrangement with those instructing him, fulfil any Joint Controller responsibilities he may have under relevant data protection legislation.

Judicial Appointments

  • Recorder (2018)
Show footer