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.