What was a Reserve Battalion of Infantry?

Other than the very smallest, most of the British infantry regiments had a number of Reserve Battalions during the Great War. They were responsible for training of recruits and of men returning to duty after being in medical care or away for any other reasons.

Army Council Instruction 45 of 1917 gave a new definition to their standard size of organisation. This replaced the definition of Army Council Instruction 1258 of 1915 and applied to regiments of the line (both regular and Territorial Force): that is, not to the Guards or any regiment that was not infantry. The new organisation was laid down as follows:

The reserve battalion would be organised as a headquarters and six companies.


Battalion headquarters

Headquarters would comprise of

  • 1 Lieutenant-Colonel, commanding
  • 1 Major, second in command
  • 1 Adjutant
  • 1 Quartermaster
  • 3 Warrant Officers Class I (one as Sergeant Major, one as Bandmaster, one (an Acting WO I) also as a Sergeant Major)
  • 2 Warrant Officers Class II (both as Quartermaster Sergeants, one of whom would be an Acting WOII)
  • 1 Colour Sergeant instructor in musketry
  • 1 Orderly Room Sergeant
  • 2 Orderly Room clerks
  • 1 Sergeant-Drummer
  • 1 Signalling Sergeant
  • 1 Pioneer Sergeant
  • 1 Sergeant-Shoemaker
  • 1 Sergeant-Cook (if the battalion strength reached more than 2000 men, a second Sergeant-Cook would be added)
  • 24 Drummers or Buglers (all of whom would be in meidical category A4 or C)
  • 4 Signalling Corporals
  • 60 Signallers (of whom 5 could be Lance Corporals)
  • 10 Pioneers (of whom two would be Cold-Shoers)
  • 16 Stretcher Bearers

This totals 132 officers and men. Highland regiments could also have one Sergeant-Piper.


The six companies would comprise in total of

  • 6 Majors or Captains, commanding
  • 30 Subalterns (Lieutenants or Second Lieutenants). Of these there would be four specialists: musketry; bombing; physical and bayonet training; signalling. One would also act as assistant Adjutant. Two additional officers (rated as fit for light duty) would be added for each 100 soldiers at medical rating A3 that were with the battalion.
  • 1 Adjutant
  • 1 Quartermaster
  • 6 Company Quartermaster Sergeants
  • 54 Sergeants
  • 72 Corporals
  • 1260 Privates

This totals 1332 officers and men. Men of A3 medical grade would be counted as supernumerary.

The establishment for Extra Reserve Battalions and Territorial Reserve Battalions differed somewhat and pages will be added on those in due course.

Which reserve battalions existed?

See each regiment’s page for full details.


The infantry regiments

Training to be a soldier

Definitions of other types of units