Police authority in the context of "Metropolitan Police Authority"

A police and crime commissioner (PCC; Welsh: comisiynydd yr heddlu a throseddu) is an elected official in England and Wales responsible for generally overseeing police services. A police, fire and crime commissioner (PFCC) is an elected official in England responsible for generally overseeing both police and fire services. Commissioners replaced the abolished police authorities. The first commissioners were elected on 15 November 2012.

The UK government intends to abolish commissioners at the end of the incumbents' terms in 2028, with oversight of police services to be transferred to devolved mayors, or to policing committees run by council leaders.

The Northern Ireland Policing Board (Irish: Bord Póilíneachta Thuaisceart Éireann, Ulster-Scots: Norlin Airlan Polisin Boord) is the police authority for Northern Ireland, charged with supervising the activities of the Police Service of Northern Ireland (PSNI). It is a non-departmental public body composed of members of the Northern Ireland Assembly and independent citizens who are appointed by the Minister of Justice using the Nolan principles for public appointments.

There are a number of agencies that participate in law enforcement in the United Kingdom which can be grouped into three general types:

• Territorial police forces, who carry out the majority of policing. These are police forces that cover a police area (a particular region) and have an independent police authority. Current police forces have their grounding in the Police Act 1996 (in England and Wales), a combination of Police (Scotland) Act 1967 and Police and Fire Reform (Scotland) Act 2012 (in Scotland) and the Police (Northern Ireland) Act 2000 (in Northern Ireland), which prescribe a number of issues such as appointment of a chief constable, jurisdiction and responsibilities.
• National law enforcement bodies, including the National Crime Agency and national police forces that have a specific, non-regional jurisdiction, such as the British Transport Police. The Serious Organised Crime and Police Act 2005 refers to these as 'special police forces', not including the NCA which is not a police force. In addition, there are non-police law enforcement agencies, whose officers are not police officers, but still enforce laws, and other bodies with solely investigatory powers.
• Miscellaneous police bodies, mostly having their foundations in older legislation or common law. These are responsible for policing specific local areas or activities, such as ports and parks. Before the passing of recent legislation such as the Serious Organised Crime and Police Act 2005, they were often referred to as 'special police forces'; care must therefore be taken in interpreting historical use of that phrase. These constabularies are not within the scope of the legislation applicable to the previously mentioned organisations but can still be the subject of statutes applicable to, for example, docks, harbours or railways. Until the passing of the Railways and Transport Safety Act 2003, the British Transport Police was such a force.

Most law enforcement in the United Kingdom is carried out by territorial police forces that police the general public and their activities. The other types of agencies are concerned with policing of more specific matters.

Law enforcement in the United Kingdom is organised separately in each of the legal systems of the United Kingdom: England and Wales, Scotland, and Northern Ireland. Most law enforcement duties are carried out by police constables of a territorial police force.

As of 2021, there were 39 territorial police forces in England, 4 in Wales, one in Scotland, and one in Northern Ireland. Each is responsible for most law enforcement and crime reduction in its police area. The territorial police forces of England and Wales are overseen by the Home Office and by a police and crime commissioner or other police authority, although they are operationally independent from government. The British Transport Police (BTP), the Ministry of Defence Police (MDP), and the Civil Nuclear Constabulary (CNC) provide specialist policing services in England, Scotland and Wales. The National Crime Agency (NCA) is primarily tasked with tackling organised crime and has been compared to the Federal Bureau of Investigation (FBI) in the United States.