Crime Branch

The Criminal Investigation Department (CID) is the branch of all territorial police forces within the British Police, and many other Commonwealth police forces, to which plain clothes detectives belong. It is thus distinct from the Uniformed Branch and the police intelligence Special Branch.

The Metropolitan Police Service created a Detective Branch in 1842 with eight plainclothes detectives thirteen years after it was established in 1829. Detective units were set up in other forces from the mid-nineteenth century onwards in the large provincial cities and towns and in the City of London. In 1854, the Nottingham Borough Police established the Criminal Investigation Department (CID).

On 8 April 1878, the Metropolitan Police Service Detective Branch was reformed into the Criminal Investigations Department 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.

CID officers are required to have had at least two years as a uniformed officer 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 a fully fledged Detective Constable (DC). CID officers are involved in investigation of major crimes such as rape, murder, serious assault, fraud, and any other offences that require complex detection They are responsible for acting upon intelligence received and then building a case.

In the United Kingdom, smaller police stations usually have more uniformed officers than CID officers, typically five Detective Constables (DC) with a Detective Sergeant (DS) in overall command. In larger stations many DCs, DSs and Detective Inspectors will be present under the overall responsibility of the Detective Chief Inspector.

Contrary to 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.

...
Wikipedia