Head constable
Head constable was a rank used in some British and British colonial police forces, and is still used in the Indian police.
England
In the Liverpool City Police and a few very small borough police forces in the United Kingdom, the head constable was the chief officer, equivalent to the chief constable in other forces. The head constable of Liverpool was renamed the chief constable in the early 1920s. Winchester City Police kept the term 'Head Constable' until 1943, when they were amalgamated with Hampshire Constabulary.
India
Head constable in the Indian police is equivalent to sergeant in police forces in other countries. Head constables wear three point-down chevrons on their sleeve or three bars on their epaulettes.[1]
Ireland and colonial police forces
In the Royal Irish Constabulary, Royal Ulster Constabulary (until its reorganization in 1970), and some colonial forces such as the Palestine Police, head constable was a rank between the sergeant and inspector grades, roughly equivalent to a warrant officer in the Army. In colonial forces, it was usually a rank held by Europeans only. Some colonial forces also had a higher rank of head constable major.