<P> On 8 April 1878, the Metropolitan Police Service Detective Branch was reformed into the CID by C.E. Howard Vincent . Originally, it was under the direct command of the Home Secretary, but since 1888 has been under the authority of the commissioner . </P> <P> Criminal investigation department officers are required to have had at least two years as uniformed officers before applying to transfer to the branch, and receive further training when they do so . While training they are referred to as a trainee detective constable (TDC) and after completing the national Initial Crime Investigators' Development Programme, typically taking around two years, they become fully fledged detective constables (DCs). CID officers are involved in the investigation of major crimes such as rape, murder, serious assault, and fraud . They are responsible for acting upon intelligence received and then building a case . </P> <P> In the United Kingdom, smaller police stations usually have more uniformed officers than CID officers, typically five DCs with a detective sergeant (DS) in overall command . In larger stations many DCs, DSs and detective inspectors are present under the overall responsibility of a detective chief inspector . </P> <P> Contrary to the practice of police forces of many other nations, detectives are not automatically senior to uniformed officers and hold the same ranks . The head of the CID in most police forces is a detective chief superintendent . </P>

What does ds stand for in uk police