Mark Deem


Personal Profile

Mark is a Disputes Partner in the Innovation Department and a specialist in technology, media and telecoms (TMT) litigation, contentious privacy and cyber security issues and financial services disputes.

He has considerable experience of complex domestic and cross-border litigation, international arbitration and regulatory matters. He has conducted litigation in all commercial divisions of the English High Court, Court of Appeal, Supreme Court and Court of Justice of the EU; represented clients in international arbitration proceedings under the rules of the ICC, LCIA, RIDR and IFTA; and has a broad experience of mediation and other dispute resolution mechanisms.

Mark is a solicitor-advocate, with rights to appear in all courts in England & Wales and is well known for his proficiency in managing clients' exposure to the risk and cost of commercial disputes through the innovative use of ATE insurance, third party and other litigation funding arrangements.

He is also co-author of the forthcoming book, AI on trial, examining the legal, regulatory and ethical framework needed to deploy AI in safe and acceptable manner and is Editor of the soon-to-be-published Global Data Review Guide to Data.

Key Experience

  • Advising mobile network operator on a £100 million contractual dispute concerning a telecommunications joint venture; leading case on the meaning and operation of joint venture agreements and dormancy rules in the telecommunications sector;
  • Advising in relation to a multi-million pound dispute concerning the delayed implementation of an IT platform and associated services to the insurance sector and the availability of certain rights of fault-based termination;
  • Acting for one of UK's leading outsourcing companies in relation to dispute concerning functionality issues in a platform for HR and payroll systems. Issues raised concerned scope creep, contractual variation and rights of fault and no fault termination;
  • Acting for a founder of a "hologram" projection technology business concerning shareholder rights and licensing arrangements;
  • Acting for several financial institutions and FTSE 100 companies in relation to data breach issues, leading to notifications to regulatory bodies (including the FSA and the ICO) and Parliament;
  • Conducting an internal investigation concerning a major cyber event on the technology platforms of each of a leading, global retailer and a leading UK service provider in the leisure industry;
  • Advising a corporate client concerning its strategic response to a significant cyber event, including issues relating to disclosure to affected parties, stakeholders and the forensic treatment of evidence;
  • Advising a client in the artificial intelligence space concerning the issues following the Cambridge Analytica allegations.
  • Advising on a $220 million contractual dispute concerning credit derivative swap and cross- border leasing transactions entered into with global financial services provider (including jurisdictional challenge under EC Regulation 44/2001 to Court of Justice of EU). Substantive proceedings raise issues of mis-selling of financial products and the doctrine of ultra vires;
  • Acting for a leading provider of a cryptocurrency wallet in the context of a ‘suicide blocking’ of its accounts;
  • Advising a start-up life sciences company in relation to a dispute concerning its corporate officers and shareholders;
  • Privacy counselling concerning deployment of wearables and sharing of health data with mobile devices.

Career History

Partner, Mishcon de Reya LLP
Partner, Cooley LLP
Partner, Edwards Wildman Palmer LLP
Partner, Addleshaw Goddard LLP
College of Law, Guildford, LPC, 1998
Downing College, Cambridge, MA, 1997

Articles and Publications

  • Author, "Liability following a data breach", chapter in book on "Cyber Security: Law and Guidance", published by Bloomsbury Professional, 2018 edition
  • Author, "At a turning point - AI is poised to have a transformational impact on people, business, governments and societies - particularly in healthcare - but we must get the regulatory framework right," CIR/Continuity Insurance & Risk, July 2018
  • Author, ”Law vital to the future of artificial intelligence," Economia, 18 October 2017
  • Author, "The tough road to finding justice after a security incident," Computer Fraud & Security, December 2016
  • Co-Author, “Insurers and brokers should start marking Brexit contingency plans,” Insurance Day, Feb.18, 2016
  • Co-author, "The UK's EU Referendum: Contingency Planning Against #BREXIT," Global Banking & Finance Review, February 2016
  • Author, "Combatting cyber-attacks in the health insurance sector," Life Insurance Magazine, August 2015
How can we help you?

How can we help you?

Subscribe: I'd like to keep in touch

If your enquiry is urgent please call +44 20 3321 7000

Crisis Hotline

COVID-19 Enquiry

I'm a client

I'm looking for advice

Something else