From: Order of Battles of Divisions: Appendix 1
On the 6th August 1914 Parliament sanctioned an increase of 500,000 men for the Regular Army, and on the 11th August a proclamation called on 100,000 men to enlist immediately for 3 years or for the duration of the War.
Army Order 311, issued on the 16th August, dealt with this augmentation of the Army; but this Army Order was cancelled, and on the 21st August Army Order 324 was substituted for it. The latter Order stated that H.M. the king approved the addition to the Army of six divisions (8th to 13th) and Army Troops.
Army Order 324 was itself amended on the 11th September by Army Order 382, which directed that the 8th (Light) Division was to become the 14th (Light) Division;* the first augmentation of the Army would then consist of the 9th to 14th Divisions and Army Troops. Army Order 382 also authorized an addition to the Army of another six divisions (15th to 20th) and Army Troops. But recruits were pouring in** and on the 13th September Army Order 388 gave formal approval for the addition to the Regular Army of yet another six divisions (21st to 26th) and Army Troops.
The composition of each of the new divisions the nomenclature of the new formations and units alloted to each of the divisions, as well as the particular battalions which were to be raised as Army Troops, were given in Appendices to Army Orders 324, 382, and 388.
Army Order 324 directed that the new battalions were to become additional battalions of the Regiments of Infantry of the Line, and the battalions would be given numbers following consecutively on the existing battalions of their regiments, distinguished by the word “Service” in brackets after the number. Analogous arrangements (without the addition of the word “Service”) were made of the numbering of the Field Artillery Brigades, Field Companies R.E., and Field Ambulances R.A.M.C.
Army Order 324 also gave instructions that, under the administration of the Home Commands, all recruits were to be clothed and equipped at depots – if sufficient clothing and equipment existed. Subsequently recruits would be collected at the training centres at which the new brigades and divisions were to be formed under the divisional generals.
Finally, Army Order 389 (issued on the 14th September) stated that the several additions to the Army would be organised and known as follows:-
9th to 14th Divisions and Army Troops – First New Army
15th to 20th Divisions and Army Troops – Second New Army
21st to 26th Divisions and Army Troops – Third New Army
The eighteen divisions, formed from the men who enlisted in August and September 1914, served and fought in six different theatres of war.
* The formation, from troops of overseas garisons, of the 8th (Regular) Division – 23rd, 24th, and 25th Infantry Brigades – between 19th September and 2nd October, 1914, was the reason for the renumbering of the 8th (Light) Division and its infantry brigades. The 8th Division disembarked in France early in November, 1914, and served in France for the remainder of the Great War.
** 500,000 men were raised by the 15th September, 1914.