Adamson was a member of the judging committee of the Museum of the Year Awards from 1979 to 1983, and has donated to the National Library of Wales. He served the Order of St John of Jerusalem from 1981 to 2008, becoming Deputy Director of Ceremonies of the Priory of England and the Islands (the Isle of Wight, the Isles of Scilly, the Channel Islands and the Isle of Man). From 19 October 2012 until 11 October 2013 Adamson served as Master (and from 2015, Senior Court Assistant) of the Worshipful Company of Curriers of the City of London and during his term of office he launched "The Curriers' Company London History Essay Prize", which is competed for annually by young graduates of British universities. As Master of the Curriers' Company, he established sixteen annual prizes in mathematics and history for pupils aged 14 to 15 at four London academies. In 1976 he became a liveryman of the Haberdashers' Company. His personal interests include the history of religion and genealogy. He is also an enthusiastic art collector, mainly of English, French and Italian paintings, including a work of Eugène Isabey, and drawings of the 18th and 19th centuries. Adamson and his wife divide their time between homes in Kent and Polperro, Cornwall and continues to contribute much on the history of Cornwall. "The Genesis of Le Cousin Pons", substantially the text of Adamson's (BLitt) thesis, is a detailed study of the manuscript and proof-sheets of this very late work. Tracing the progress of the novel through its various editions, it reveals the full extent of Balzac's improvisation from novella to full-length masterpiece. "Illusions Perdues", a critical study of what is Balzac's most mature work, outlines its strong autobiographical element, analysing contrasts of Paris and the provinces, the purity of the artist's life and the corruptions of journalism, and the ambiguity of Balzac's narrative outlook. Major themes of the book are that in "fiction" is truth and in "truth" fiction, and that "Illusions Perdues" is the first novel by any writer to highlight the shaping of public opinion by the media, usually done in the pursuit of power or money. "Blaise Pascal" considers its subject from biographical, theological, religious and mathematical points of view, including the standpoint of physics. There is a chapter on the argument of the Wager. The analysis is slightly inclined in a secular direction, giving greater emphasis to Pascal's concern with the contradictions of human nature, and rather less to his deep and traditional preoccupation with Original Sin.