Firearms unit

A firearms unit is an 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 terrorists and 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 for some forces. 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, Trojan or SC&O19. Within the media it is sometimes compared to the SWAT units of the United States.

The number of firearms legally available to criminals is low due to the United Kingdom's gun laws requiring licensing and background checks to legally acquire and possess most types of firearms. In the majority of cases the presence of an armed officer can often be enough to negotiate the surrender of an armed criminal and the number of times a police firearm is deliberately discharged at suspects in the UK rarely exceeds around ten occasions per year. For example, Thames Valley Police has only used a firearm against a suspect once in its entire history.

Only three forces in the United Kingdom routinely arm officers due to the nature of their work; the Ministry of Defence Police who are responsible law enforcement on MOD property, the Civil Nuclear Constabulary who guard civil nuclear facilities, and the Police Service of Northern Ireland.

On 13 January 2016, following the November 2015 Paris attacks it was decided to significantly increase the numbers of armed officers in London. The then Commissioner of the London Metropolitan Police, Sir Bernard Hogan-Howe has decided that he will double the number of armed officers and promised a 'significant' further announcement.