From Longman Dictionary of Contemporary Englishbadge of officebadge of officeBritish EnglishPGO an object which shows that you have an official position Mayors wear chains around their necks as badges of office. → badge
Examples from the Corpus
badge of office• His badge of office, a large gold key, hung round his neck on a silk ribbon.• And there were more badges of office.• Police are quizzing staff and contractors in Middlesbrough municipal buildings after the theft of the nine-carat chains and two badges of office. 