A Basic Command Unit is the largest unit into which territorial British Police forces are divided. This may actually be called a BCU or may have another designation, such as Division

Police division

A division was the usual term for the largest territorial subdivision of most British police forces. In major reforms of police organisation in the 1990s divisions of many forces were restructured and retitled Basic Command Units , although some forces continue to refer to them as divisions.The...

 or Area. There are 228 BCUs (including those with different titles such as division etc.) in England and Wales.

Most forces are divided into at least three BCUs and some have many more. Most BCUs are further subdivided into smaller units. The BCU is usually commanded by an Inspector

Inspector

Inspector is both a police rank and an administrative position, both used in a number of contexts. However, it is not an equivalent rank in each police force.- Australia :...

.

The Metropolitan Police

Metropolitan Police Service

The Metropolitan Police Service is the territorial police force responsible for Greater London, excluding the "square mile" of the City of London which is the responsibility of the City of London Police...

 use the term Borough Operational Command Unit (BOCU) for regional units (which are based on the 32 London boroughs) and Operational Command Unit (OCU) for other units, for example the Aviation Security OCU

Aviation Security Operational Command Unit

The Aviation Security Operational Command Unit is a Specialist Operations unit of London's Metropolitan Police Service. The unit is responsible for providing law enforcement and security for both Heathrow and London City airports...

.

Warwickshire Police

Warwickshire Police

Warwickshire Police is the territorial police force responsible for policing Warwickshire in England. It was known as Warwickshire Constabulary until 2001. It is the second smallest territorial police force in England and Wales after the City of London Police, with only 998.6 regular officers as...

 has abolished BCUs, the first British territorial police force to do so. The force is now divided directly into five Districts, each headed by a Chief Inspector

Chief inspector

Chief inspector is a rank used in police forces which follow the British model. In countries outside Britain, it is sometimes referred to as chief inspector of police .-Australia:...

. These were formerly grouped into two Areas (BCUs), North and South, each headed by a Chief Superintendent.