The
Criminal Investigation Department (
CID) is the branch of a police force to which most plainclothes detectives belong in the United Kingdom and many Commonwealth nations. A force's CID is distinct from its Special Branch. The name derives from the CID of the Metropolitan Police, formed on 8 April 1878 by C. E. Howard Vincent as a re-formation of its Detective Branch. British colonial police forces all over the world adopted the terminology developed in the UK in the 19th and early 20th centuries, and later the police forces of those countries often retained it after independence. English-language media often use "CID" as a translation to refer to comparable organisations in other countries.