Police constale

There are two main definitions of a constable in the United Kingdom:
 * The lowest rank of a police force.
 * A legal term for an officer with the powers of a police officer.

The latter usage is mainly used in formal contexts, including legislation such as the Police and Criminal Evidence Act 1984. By this definition, all police officers are constables, even those that do not hold the actual rank of constable. Thus the head of most police forces is a chief constable, volunteer officers of any rank are known as special constables and some police forces have the word "Constabulary" in their name. There are also some constables who are not police officers, such as cathedral constables and Cambridge University constables.

Within the police itself, there are three eponymous offices bearing the legal power of constable: Police Constable, Detective Constable and Special Constable. The former two of these are paid, mostly full-time positions, while those holding the role of Special Constable volunteer their time unpaid and do so around their normal working commitments. The ranks of Police Constable and Detective Constable are often abbreviated in everyday use to PC and DC respectively. From 1919 when they were first recruited in the UK, female police officers were distinguished from their male counterparts by the prefix 'woman' before their rank (WPC or WDC). although is still sometimes used informally by members of the public.