The first British army to be sent to the Western Front was the British Expeditionary Force (BEF), which was mobilised in August 1914. It consisted of the regular army of professional soldiers and non-professional part-time volunteer regiments, known as the Territorial Force (TF), whose intended primary role was home defence. At the outbreak of the war these territorial units were given the option to serve in France; within the first three weeks, more than 70 regiments had volunteered to do so.
Under the command of Field Marshal Sir John French, the BEF initially consisted of three army corps of two infantry divisions each, a large cavalry division of four brigades, and a fifth independent cavalry brigade. By October 1914, a further army corps of two infantry divisions and three additional cavalry divisions had been formed and sent to join the BEF. The German Emperor, Wilhelm II, is said to have referred to the BEF as ‘General French’s contemptible little army’. Although this may have been a British propaganda invention, veterans of the BEF came in later years to dub themselves as ‘the Old Contemptibles’.
Pat Armstrong was in the second cavalry brigade of the first cavalry division. This brigade, under the command of Brigadier General Henry de Beauvoir de Lisle, was made up of men from the cavalry regiments of 4th (Royal Irish) Dragoon Guards, 9th (Queen’s Royal) Lancers and 18th (Queen Mary’s Own) Hussars. General de Lisle’s staff consisted of Colonel ‘Sally’ Home as General Staff Office (GSO) 1; Major Percy Hambro as GSO 2, Captain Cecil Howard as GSO 3, Captain Henry Archdale ‘Mouse’ Tomkinson as assistant provost marshal of the first cavalry division, Captain Hardress Lloyd as aide-de-camp, Lieutenant ‘Pat’ Armstrong as aide-de-camp, and Frederic Coleman, an American volunteer motor driver.
The British Expeditionary Force suffered catastrophic losses in the first few months of the war and had been practically wiped out by the end of 1914, necessitating the creation of a second, all-volunteer army known as the New or Kitchener’s Army.
Battalion – A military formation of about 1000 men under the command of a Lieutenant Colonel made up of two or more companies
Brigade – A military formation composed of 3 to 6 battalions under the command of a Brigade General and his staff
Division – A large military unit made up of three or four brigades and additional specialists units (engineers, medical personnel etc.) under the command of a Major General
Corps – A large military formation composed of two or more divisions under the command of a Lieutenant General operating from a stationary location
Army – A military formation consisting of several corps and support units under the command of a General