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Mourant, an international professional services firm with law at its core, has strengthened its Dispute Resolution practice with the hire of distinguished Guernsey litigator, John Greenfield.
After five years’ practising in England (undertaking both criminal defence and civil litigation), at the beginning of his career, John moved to Guernsey in 1980 to work for an international merchant bank. Following this, he joined a leading Guernsey law firm and, the same year, qualified as a notary public and was called to the Guernsey Bar. He was subsequently elected as head of the Guernsey Bar in 2008 and re-elected to the role in 2010.
John’s specialisms span the full range of major litigation and advocacy work, including asset tracing, multi-jurisdictional disputes, and commercial and trust litigation. He has been involved in some of the most significant litigation cases before the Royal Court of Guernsey and the Guernsey Court of Appeal, and is one of the few Guernsey advocates to have appeared as counsel before the Privy Council. Notably, John was a member of the committee which completely overhauled Guernsey’s civil procedure in 2008.
John is also the founding member of FraudNet, a body of the world’s leading fraud lawyers established by the International Chamber of Commerce.
John has been ranked in Chambers and Partners for over 20 years, and currently holds the ranking of ‘Senior Statesperson’ in Offshore: Dispute Resolution. In Legal 500 UK 2025, John is named in the Hall of Fame, a prestigious ranking which recognises lawyers who are at the top of their field for their long-standing involvement in market-leading work.
Commenting on his appointment, John said:
“Mourant is going through a pivotal moment in its growth, and it’s a very exciting time to be joining the firm. Mourant’s Guernsey Dispute Resolution practice has an indomitable reputation in the region and I look forward to working closely with my new colleagues and drawing on my expertise to add value to our clients.”
Head of the Guernsey Dispute Resolution team, Abel Lyall, added:
“John is a highly experienced and impressive litigator and it’s a huge honour to welcome him to our firm. He has an impeccable reputation and will greatly enhance the breadth and scope of our litigation offering.”
John’s appointment is the latest high-profile hire for Mourant. Former Kirkland & Ellis Partner, Brad Hillson, was appointed Global Head of Private Capital in May, with Tom Grogan (previously Head of Emerging Technology at Mishcon de Reya) joining as Chief Transformation Officer the following month (June 2025).