Collar number

A collar number, also known as a shoulder number, force identification number (FIN) or occasionally as force number (although this can also refer to the ID number of a force itself), identifies police officers, police community support officers (PCSO), special constables (SC or SPC) and some police staff in UK police forces – other law enforcement agencies, such as HM Prison Service, have also adopted identification numbers. Although now displayed on epaulettes (i.e. on the shoulder), it is still commonly referred to as a collar number. Although most forces issue a collar number to all warranted officers regardless of role, only uniformed officers of the ranks constable and sergeant actually display the numbers. In most forces it is simply a one- to five-digit number, but in larger forces a letter code (also known as a division call sign) may be added to indicate the officer's base area or unit. In some forces different types of staff (paid ('regular') police officers, special constables, PCSOs and other police staff) are assigned different ranges of numbers, so a person's role can be deduced from the number, but these systems are force specific and there is no national standard.