Premise: The Royal Corps of Halberdiers is a fictional British regiment from Evelyn Waugh's "Sword of Honour" trilogy. In the novel, the regiment is described as being composed of four battalions: The 1st (Regular Infantry) 2nd (Territorial Army), 3rd (Commandos), and 4th (Militia). The Corps is derived from Waugh's own experiences in the Royal Marines throughout World War II.
Hypothesis: The Royal Marines may have had four battalions in it.