The British Armies of 1914-1918

The British Armies in France and Flanders

In France and Flanders, the size of the British army was eventually such that it was subdivided into five Armies. Armies were also formed at home and the force in Salonika also went by the title, although those in Gallipoli, Italy and Palestine did not.

Army History
First Formed in France on 26 December 1914, initially under the command of General Sir Douglas Haig. Remained on the Western Front throughout the rest of war.
Second Formed in France on 26 December 1914, initially under the command of Sir Horace Smith-Dorrien. Later under the command of Sir Herbert Plumer, the Army HQ moved to Italy between 13 November 1917 and 17 March 1918. Other than for this period, Second Army was always associated with the Ypres Salient.
Third Formed in France on 13 July 1915, initially under the command of General Sir Charles Monro.
Fourth Formed in France on 5 February 1916, under the command of Sir Henry Rawlinson. Was renamed Second Army when Plumer moved to Italy, and reverted to Fourth Army when he returned.
Fifth On 22 May 1916, the Reserve Corps HQ under Sir Hubert Gough became the Reserve Army, which was then renamed Fifth Army. Seriously damaged by the great German assault in March 1918, it was renamed Fourth Army on 2 April, and its HQ became HQ Reserve Army once again. It was restored as HQ Fifth Army on 23 May 1918 under the command of Sir William Birdwood.

The British Armies in other theatres of war

British Salonika Army Formed in Salonika from October 1915; the Army HQ became a GHQ in January 1917.
First (Home Forces) Formed in UK on outbreak of war and disbanded 12 March 1916.
Second (Home Forces) Formed in UK on outbreak of war and disbanded 12 March 1916.
Third (Home Forces) Formed in UK 6 September 1914 and disbanded 11 December 1915.
Northern (Home Forces) Formed in UK 11 April 1916 and disbanded 16 February 1918.
Southern (Home Forces) Formed in UK 11 April 1916 and disbanded 16 February 1918.

What was an Army?

In 1914 the British Expeditionary Force in France and Flanders consisted of a General Headquarters and a number of Corps. First and Second Armies were formed only very late in 1914 and an official establishment was not defined until March 1915.

Once defined, the Army was composed of an Army HQ which commanded at least two Corps, with various units attached as Army Troops. Army HQ reported up to GHQ. The Army HQ consisted of 31 officers and 106 other ranks. The Corps were not permanently attached to an Army, and neither were the Divisions below them. The attached Army Troops units varied greatly and day to day; the establishments shown below really only applied to the five Armies in France and Flanders.

The number of Corps under the command of the Army remained nominally at two, but could be increased if fighting conditions required – for example, when an Army was ordered to an offensive. The Army HQ generally remained geograohically fixed in place, as did the Corps HQ, while the Divisions were moved around and passed from control of one Army to another.

The Army HQ had under its command, in addition to the two or more Corps, various bodies of troops required to supply and maintain the tactical units and to provide extra strategic firepower. These troops included artillery, engineers, transport, medical, machine gun, veterinary, labour and mounted troops. The composition shown is typical of each Army as at November 1918:

Heavy Artillery

The artillery of an Army consisted of the following Heavy and Medium Artillery:

  • 2-4 Mobile Brigades of Heavy and Medium Artillery
  • 1-6 Mixed Brigades of Heavy and Medium Artillery
  • 3-5 Brigades of 8-inch Howitzers
  • 2-6 Brigades of 9.2-inch Howitzers
  • 1-3 Army Brigades of the Royal Garrison Artillery
  • 4-10 Batteries of 6-inch guns
  • 6-11 Batteries of heavier guns

Field Artillery

  • 4-16 Army Brigades of the Royal Field Artillery
  • 3-5 Anti-Aircraft Batteries of the Royal Garrison Artillery

Machine Guns

2-4 Machine Gun Battalions came under Army command, and there was one Motor Brigade MGC shared between them.This firepower was in addition to the guns at Divisional level.

Royal Engineers

The engineers of the Army were mainly employed on building and maintaining large-scale supply networks (roads, bridges, pipelines etc), or were specialist technical units. They were in addition to the Field and Signals Cmapnies at Corps and Divisional level.

  • 2 Field Companies
  • 2-3 Advanced RE Parks
  • 9-16 Army Troops Companies
  • 1-2 Siege Companies
  • 5-8 Tunnelling Companies
  • 1 Electrical and Mechanical Company
  • 1 Army Workshop Company
  • 1 Field Survey Battalion
  • 4-11 Anti-aircraft Searchlight Sections and a number of searchlight companies
  • 1 Pontoon Park
  • 1 Tranportation (Works) Company
  • Various drainage or barge companies
  • 2 Forestry Companies

The RE would also provide signals, printing and stationery units:

  • 1 Army Signal Company
  • 1 Motor Mobile Pigeon Loft
  • 14 horse-drawn Pigeon Lofts
  • 3 Fixed Pigeon Lofts
  • The Army ran on forms and instructions, printed by the hundreds of thousands. An Army would have its own photographic and printing sections RE.

Royal Army Medical Corps

In addition to the RAMC units at Divisional level, the Army would command

  • 4 Motor Ambulance Convoys
  • 12 Casualty Clearing Stations
  • 3 Medical Stores Depots
  • 4 Mobile Laboratories
  • 2 Mobile X-Ray units
  • 1 Mobile Dental unit
  • 1 Stationary Hospital
  • 10 Sanitary Sections and 5 Sanitary Squads

Army Veterinary Corps

3 horse evacuating stations.

Miscellaneous units for manual work and guard duties

  • 1 Garrison Battalion
  • 3 Garrison Companies
  • 1 Anti-aircraft Company, infantry
  • 7 Labour Group HQs, consisting of 39 Labour Companies, 10 Area Employment Companies, 2 Area Employment (Artisan) Companies, 1 Agricultural Company, and 17 Chinese Labour Companies.

What were “Army Troops”?

The British Army of 1914-1918 sometimes used very confusing terminology. “Army Troops” was a term given to any unit (which could be infantry, engineers, artillery etc) that was under the direct command of an Army HQ, as opposed to the command of one of its subsidiary levels such as a Corps. Thus a Field Artillery Brigade was called an Army Brigade if it reported to the Commander Royal Artillery of an Army. An Army Troops Company of the Royal Engineers reported to the Commander Royal Engineers of an Army.


More aspects of the British Order of Battle