International Tax Practice

Counsel and expert evidence in tax disputes involving international issues.

Independent specialist advice to other professionals on solving cross-border tax problems.

International aspects of United Kingdom taxation.


Advice and advocacy at all stages of investigations and disputes between tax authorities and taxpayer's as well as tax-related commercial, contractual and professional liability disputes, whether they are settled by negotiation, alternative dispute resolution or end up in court.


Advice on taxation of international transactions, investment and work including double tax relief tax treaties and EU law affecting taxation, transfer pricing, residence, withholding taxes, permanent establishments, cross-border compliance and cooperation

Professional Experience


Jonathan Schwarz’s professional career has been devoted to international taxation. Before practising as a Barrister, he spent 10 years in two major London Law firms as a tax partner.

Prior to that, he practised in Canada including seven years running the London office of a large Canadian law firm. Over the period, he has gained hands-on, practical experience of cross-border tax problems and an international perspective on most areas of taxation. 



  • Barrister England and Wales
  • Barrister Ireland
  • Barrister and Solicitor, Alberta, Canada
  • Advocate South Africa
  • Fellow of the Chartered Institute of Taxation
  • BA, LLB: University of the Witwatersrand, South Africa
  • LLM: University of California, Berkeley


  • A ‘real expert’ and ‘a go-to person for international tax disputes.’ Legal 500 2013  

  • Commended for ‘encyclopaedic knowledge of double tax treaties’ Chambers Guide to the Legal Profession 2011

  • "He's client-friendly and works hard, and is clearly amongst the best international tax barristers at the moment." Chambers Guide to the Legal Profession 2015

  • “Lauded for brilliant handling of cross-border tax problems.”   Who's Who Legal UK Bar 2016

  • “The leading advisor on international tax treaty issues.” Legal 500, UK Bar 2019

  • “an expert in tax litigation, known for his adept handling of complex cross-border and international tax disputes.” Who’s Who Legal UK Bar 2019

  • "A guru on matters of international tax law." Chambers & Partners 2022

  • "He is excellent and always goes the extra mile for clients." Legal 500 2023

  • One of the world’s leading practitioners in Who's Who Legal: UK Bar 2022 2023

  • Highly Regarded in Tax controversy and World TP ITR World Tax, 2023