A Field Force in British and Indian Army military parlance is a combined arms land force operating under actual or assumed combat circumstances[1] usually for the length of a specific military campaign.
A Field Force would be created from the various units in an area of military operations and be named for the geographical area. Examples are-
In Australia a Field Force comprises the units required to meet operational commitments.[2]
In the United States, during the Vietnam War the term "Corps" was used for various parts of South Vietnam i.e. "I Corps". To avoid confusion the Corps sized military command that controlled U.S. Army Divisions and other units was called a "Field Force" such as I Field Force and II Field Force. Unlike an Army Corps, the Field Force had other functions such as liaision with South Vietnamese and Civil Affairs functions and was flexible enough to have other subordinate units assigned to it.[3]
The US Army refers to task forces as temporary organisations of military units for a specific mission though they usually may be of battalion size. Task Forces were formerly named after the unit commander, such as Task Force Smith at the beginning of the Korean War. Similar temporary military formations in British, Imperial, or Commonwealth units were formerly known by the name of the Commander i.e. Layforce for Colonel Robert Laycock's command.
In counter insurgency type campaigns, select and specially trained units of police armed and equipped as light infantry have been designated as police field forces who perform paramilitary type patrols and ambushes whilst retaining their police powers in areas that were highly dangerous.[4]
Examples of these are: