William George (Bill) Crampton, PhD, MEd (5 May 1936 – 4 June 1997) was a British vexillologist. His chief legacy, the Flag Institute, has hundreds of members in the UK and overseas. He was recognised as Britain's foremost authority on flags by government agencies, the flag trade, the media, publishers, librarians and vexillologists of all ages and backgrounds. He was also renowned internationally, and his status was recognised by his election as President of Fédération internationale des associations vexillologiques, the International Federation of Vexillological Associations.
He was educated at Wallasey Grammar School and then – after National Service in Egypt in 1954-56 – at the London School of Economics where he studied sociology. He became a teacher at Gravesend Technical College, and in Ghana, and in 1963 was appointed as an adult education organiser for the West Lancashire and Cheshire Workers Educational Association.
When asked when he first became interested in flags, Crampton responded that it was like being asked when he started breathing. He was fascinated by flags from an early age, and began research as a 14-year-old schoolboy, when he realised that some flags in his atlas were obsolete. Thereafter he devoured all the flag knowledge he could find, scouring libraries and bookstores for every available book. At university, in the army, and while working overseas, chances for flag research were limited but he nevertheless took every opportunity to gain more knowledge.
In 1963, while working in adult education, he was able to resume vexillology and contacted Whitney Smith, the foremost American flag expert and "father" of the international vexillological movement. In 1967 Smith held a meeting in London at which Crampton met others devoted to flags, including Ted Barraclough, then editor of the standard British reference book Flags of the World. The meeting was Crampton's launching pad. Active in the Flag Section of the Heraldry Society, he edited its newsletter from its introduction in 1969. In 1971 he formed the Flag Institute and became its director, with Barraclough as chairman. The newsletter became the Institute's journal Flagmaster. In the same year, at the Fourth International Congress of Vexillology in Turin, Italy, the Flag Institute joined the FIAV and successfully proposed that the 1973 Congress be held in London.