Mark Dunster > Carey Olsen > St Peter Port, Guernsey > Lawyer Profile

Carey Olsen

Work Department

Dispute Resolution and Litigation; Employment, Pensions and Incentives; Restructuring and Insolvency; Regulatory; Corporate; Investment Funds; Private Client


Mark is a partner specialising in litigation, compliance and financial regulatory matters. He undertakes a wide variety of commercial and civil litigation including insolvency work. He also advises institutions on regulatory matters including anti-money laundering, data protection, employment law, eGaming and renewable energy. He is an author of books on anti-money laundering and data protection.

Mark holds the International Association of Privacy Professionals “Certified Information Privacy Professional/Europe” qualification as part of his data protection practice. He is the former Chairman of the Guernsey Association of Compliance Officers and of the Guernsey Bar Association, known as Bâtonnier.

Mark is a current member of the States of Guernsey legislative review committee advising on the implementation and drafting of new laws and ordinances. Mark is also a tribunal member (that is judge) on various appeal tribunals including those on planning and social security legislation. He was also appointed as Adjunct Professor of Civil Litigation by the Guernsey Bar.


Mark was called as a barrister in 1994 and practised in London before returning to his native Guernsey where he qualified with the firm as an advocate in 1997. He has been a partner since 2001 and became a Notary Public in 2006.

He acts as both an executive and non-executive director of a number of Guernsey (and non Guernsey) companies in sectors as wide as trust and fiduciary services, electronic gaming, credit card payment processing, commercial real estate and investment holding. Mark holds the Institute of Directors Chartered Director status. Mark was a member of Guernsey’s Health and Social Services Department between 2004 and 2008. He was formerly Connétable of St Pierre du Bois and is now a Douzenier for that parish.




Elizabeth College, Guernsey; Keele University (1992); College of Law (1993 CPE); Inns of Court School of Law (1994 English Bar Finals); University de Caen Basse-Normandie (1997 Certificat d’Etudes Juridiques Francaise et Normandes); 2001 Diploma in Civil and Commercial Litigation; 2003 Masters in Advance Civil and Commercial Litigation; Notary Public 2006.

Lawyer Rankings

Guernsey > Dispute resolution

(Leading individuals)

Mark DunsterCarey Olsen

Carey Olsen offers a full offshore litigation service to clients, covering commercial and trust litigation, as well as corporate and banking work, IP and data protection issues, and claimant-side professional negligence cases. It also has a separate contentious restructuring and insolvency group, led by David Jones . The team is often at the forefront of disputes, and has an increasingly active practice involving fintech and crypto assets and their regulation. Elaine Gray  is the department head, and is a veteran Guernsey litigator. Tim Corfield  focuses on commercial litigation, and the group is able to draw on the knowledge of John Greenfield, who is often instructed as senior counsel, particularly in cases involving allegations of fraud. Mark Dunster  is known for regulatory litigation and criminal cases, while senior associate Julia Schaefer is increasingly known for contentious trusts work.

Guernsey > Employment

At Carey Olsen, clients appreciate the ‘whole-team approach and support provided through the administration and management‘ of their employment matters. The group has a strength in advising on the employment aspects of corporate acquisitions, but it is most noted for representing claimants and defendants in employment-related disputes, where practice head Elaine Gray  ‘s experience comes to the fore; while Mark Dunster  handles employment issues that cross over with regulatory and criminal law. Other names to note are counsel Natasha Newell , who focuses on commercial employment law and regulatory issues, and associate Lois Madden, whose additional expertise includes data protection.