Philip was Keeper of Coins and Medals at the British Museum from 2010 to 2020, having worked in that department from 1979, principally as curator of medals. On his retirement in 2020 he was made an Honorary Research Fellow. His many books and articles include the British Museum exhibition catalogue Artistic circles: the medal in Britain 1880-1918 (1992), the major collection catalogue Italian medals, c.1530-1600, in British public collections (2003), and more recently Hard at work: the diary of Leonard Wyon 1853-1867 (2014). For many years he has been editor of The Medal, the journal of the British Art Medal Society, and was president of that society from 2008 to 2018. Since 2012 he has been president of the Fédération Internationale de la Médaille d'Art (FIDEM). He is currently working on books on coin- and medal-designers Mary Gillick (1881-1965) and Frank Bowcher (1864-1938).