Sir Arthur Watts studied law at Cambridge before becoming an assistant legal adviser at the Foreign Office (now the Foreign & Commonwealth Office) in 1956. He became Deputy Legal Adviser in 1982 and The Legal Adviser in 1987 after a lengthy career with the FCO. In 1991, he retired and began practicing law at the Bar. He has testified before the International Court of Justice in a number of instances and has participated in a number of international arbitrations. He has also served as the international mediator for succession concerns arising from the disintegration of Yugoslavia since 1996.