John specialises in commercial disputes. His specialisms include: public law and judicial review, law of contract, property law, planning law and general commercial litigation. He is a recognised leader in Jersey contract law, Jersey customary law and Jersey property law. The many high profile cases he has acted on include Les Pas Holdings Limited v. States of Jersey; J.P.M.O. and TOP Produce v. States of Jersey; Anchor Trust v. Jersey Financial Services Commission; Jersey Financial Services Commission v. Cater Allen Trust Co Ltd; Attorney General v. Bhojwani; Crociani v. Crociani and others. John was elected President of the Law Society of Jersey in 2017 and served in that office until 2021. He is also a Fellow of the Royal Historical Society.