High Quality Content by WIKIPEDIA articles! A firearms unit is a specialised, armed unit within each territorial police force in the United Kingdom. For the most part, the police forces of the United Kingdom are unarmed; however, all have firearms units to provide the police force with the capability to deal with armed criminals. A police officer cannot apply to join the firearms unit without first finishing their two year probationary period, with a further two years in a core policing role. Firearms unit is the most common name outside of the capital, while that of London`s Metropolitan Police Service is called the Specialist Firearms Command, or SCO19. Within the media it is sometimes compared to the SWAT units of the United States.