In British law and similar legal systems, a Constable has the legal powers of arrest given to him directly by a sworn oath and warrant, rather than being delegated powers that he has simply because he is employed as a Police officer. Technically this means that each sworn Constable is an independent legal official rather than simply an employee of the Police.
In many police forces, the rank of Constable is the lowest rank of a trained police officer. Though the rank of Senior Constable can sometimes mean the head of the police force in an area, the rank of Chief Constable or Commissioner is used more often to describe the head of the police force.
Other Police ranks include:
Also the additional identification of Detective is normally added for those constables who are involved in investigating crimes, rather than just policing.