The British cavalry were the first British Army units to see action during the First World War. Captain Hornby of the 4th (Royal Irish) Dragoon Guards is reputed to have been the first British soldier to kill a German soldier, using his sword, and Corporal Edward Thomas of the same regiment is reputed to have fired the first British shot shortly after 06:30 on 22 August 1914, near the Belgian village of Casteau. The following Battle of Mons was the first engagement fought by British soldiers in Western Europe since the Battle of Waterloo, ninety-nine years earlier. In the first year of the war in France, nine cavalry brigades were formed for three British cavalry divisions. Other regiments served in six brigades of the two British Indian Army cavalry divisions that were formed for service on the Western Front. Three regiments also fought in the campaign in Mesopotamia, the only other theatre of the First World War where British cavalry served.

The doctrine of the British cavalry had been highly influenced by their experiences in the Second Boer War fifteen years earlier, during which one commander had preferred using irregular units to the professional cavalry regiments. By necessity, cavalry doctrine had changed since then, with emphasis being placed on dismounted firepower and covering fire from the flanks, using machine guns and attached artillery, to support cavalry charges. The only officers to command the British Expeditionary Force on the Western Front were both cavalrymen, while the original commander of the British Cavalry Division went on to command the Egyptian Expeditionary Force during the Palestine Campaign, and another cavalryman became the Chief of the Imperial General Staff. Altogether on the Western Front, five of the ten officers who commanded the five British armies were provided by the cavalry, while another ten commanded corps, and twenty-seven served as divisional commanders.

Among other decorations for their valour, eight cavalrymen were awarded the Victoria Cross, Britain's highest award for bravery in the face of the enemy. Three of the awards came in the first month of the war. All but one of the thirty-two British regular army cavalry regiments fought in a recognised theatre of war, either on the Western Front or in the Mesopotamia Campaign, during which over 5,600 cavalrymen were killed, including several senior officers.

Background

The traditional role of cavalry in war is scouting—gathering information about the enemy's location, strength, and movements—while denying the enemy the same information about one's own forces.Badsey 2008, p.4 Other tasks include raiding into enemy territory and damaging their infrastructure and economy while avoiding conflict with enemy forces. On the field of battle, cavalry were expected to charge into and break up enemy infantry and cavalry formations.Badsey 2008, p.5 The prestige gained by participating in a cavalry charge was such that additional officers would attempt to join one whenever possible. Notable examples of this include Louis Nolan of the 15th Hussars joining the Charge of the Light Brigade in the Crimean War and Winston Churchill of the 4th Hussars joining the 21st Lancers for their charge during the Battle of Omdurman.Badsey 2008, p.18

Since 1880 British cavalrymen had been armed with carbines and swords and some carried a lance;Badsey 2008, p.6 it was not until 1903 that the cavalry were issued rifles, the same ones used by the rest of the army,Badsey 2008, p.162 although a version of the standard infantry rifle, the shorter-barreled LEC or "Lee-Enfield Cavalry Carbine Mark I" had been introduced in 1896.

The normal peacetime British Army cavalry formation was the brigade, but twice a cavalry division had been formed. The first time was during the Anglo-Egyptian War in 1882.

The second time was during the Second Boer War (1899–1901) in South Africa,Badsey 2008, p.7 the last major conflict fought by the British Army before the First World War. During the fighting in South Africa, it was the 7,000-strong mounted contingents, not the 5,000-strong regular cavalry, that led the way in tactical development. They were better armed and more efficient, if only because they had been correctly trained to use the right weapons and tactics for the conflict.Childers 1911, pp.28–30 The regular cavalry regiments were considered so unsuitable for the current conflict that General Sir Redvers Henry Buller, commanding the advance into Northern Natal, left his six cavalry regiments behind at Ladysmith, trusting in the irregular mounted forces to carry out patrols in their stead.Childers 1911, p.31

Their Boer opponents taught not only the cavalry but the whole army some lessons. In one engagement at Dronfield, 150 Boers held off the British cavalry division, which was then supported by several artillery batteries, and at Bergendal 74 men held up the entire British Army.Childers 1911, p.42 So effective were their tactics that they forced the British cavalry, if only for a short time, to leave their swords and lances behind and concentrate on their firepower. This proved to the British Army the value of a full size rifle over a carbine.Childers 1911, pp.44–49 Soon the cavalry were practising working dismounted and advancing in open order.Badsey 2008, p.89 Their change in tactics was evidenced during the charge at Klip Drift. On their way to relieve the siege of Kimberley, the cavalry used their horses and rifles instead of swords and lances to get behind the defending Boers. The charge was later described as "an ideal cavalry operation, but not a cavalry charge as the term is generally understood." Nevertheless, it would prove to be the last time that a full British cavalry division conducted a mounted charge.Badsey 2008 p.16

Following the Boer War there were calls for the disbandment of the cavalry by such notable persons as the Commander-in-Chief of the Forces Lord Roberts and Sir Arthur Conan Doyle.Badsey 2008, p.148 Between 1900 and 1903 the cavalry's share of the army budget was cut from six to under 4.5%, and recruiting for the cavalry was suspended for a year.Badsey 2008, p.153 Added to this, the Commonwealth Defence Act 1903 proposed a force of nine brigades formed by a militia, with six of the brigades planned to be mounted infantry known as light horse.Badsey 2008, p.165 In the same year, Lord Roberts appointed Robert Baden-Powell of the 5th Dragoon Guards to the position of Inspector General of Cavalry, a surprising choice as Roberts had earlier described him as being "certainly not a General".Badsey 2008, p.166 Within the year, Baden-Powell was endorsing a change in policy, recommending that instead of countering an enemy charge with a countercharge of their own, the cavalry should dismount and engage them with rifle fire.Badsey 2008, p.167 For cavalry to survive, by necessity British cavalry doctrine had to change, as the emphasis was now on dismounted firepower and cavalry charges that were supported by covering fire from the flanks, by their own machine guns, and the guns of the Royal Horse Artillery (RHA).Roy 2011, p.195 To support this change in policy, cavalrymen were now required to do two hours rifle or sword practice a day.Holmes 2005, p.111 This made them just as proficient as the infantry with their rifles. In 1908 one regiment, the 14th Hussars, recorded having 354 marksmen, 212 first class shots, 35 second class, and only four third class shots.Holmes 2005, p.379

The resulting reforms helped shape the cavalry's contribution to the British Expeditionary Force (BEF), which was established with one cavalry division supported by two brigades of horse artillery. All would be trained for the mounted charge but would also be armed with rifles, the only major power to do so. The cavalry regiments were armed with Maxim Machine Guns, which were replaced by Vickers Machine Guns from 1912. More than anything else, the issue of entrenching tools that were carried on the troop packhorses demonstrated how much the cavalry's doctrine had changed since the Boer Wars.

Organisation

In 1914, prior to the start of the First World War, there were just over 15,000 cavalrymenBadsey 2008, p.198 serving in 31 British Army cavalry regiments.Gudmundsson 2005, p.46 There were three Household Cavalry regiments and 28 line cavalry regiments consisting of seven dragoon guards, three dragoon, 12 hussar, and six lancer regiments. In the British Army the term "cavalry" was only used for regular army units. The other mounted regiments in the army, which were part of the Territorial Force reserve, were the 55 yeomanry regiments and three special reserve regiments of horse.Gudmundsson 2005, p.48 Several of the cavalry regiments, amounting to 6,000 men, were serving overseas in British India, South Africa, and Egypt.Rinaldi 2008, p.328 The 12 regiments based in Great Britain were assigned to four cavalry brigades, three regiments per brigade, identified as being part of the cavalry division for the BEF.Rinaldi 2008, p.14 After the declaration of war in August 1914, the cavalry joined the rest of the BEF in France, together with a fifth independent cavalry brigade, formed from three un-brigaded regiments then based in England.Gudmundsson 2005, p.12 British cavalry brigades were a third larger than French and German brigades, which only had two regiments.Gudmundsson 2005, p.50 To provide a reconnaissance force for the six infantry divisions, two regiments the 15th Hussars and the 19th Hussars were split up with one squadron being assigned to each infantry division. Also in August 1914, a 32nd regiment, the Household Cavalry Composite Regiment, was formed from three squadrons that were drawn from each of the Household Cavalry regiments; its existence proved short-lived as it was disbanded on 11 November 1914, with its manpower returning to their parent regiments.

Early in the war 24 reserve cavalry regiments were formed to provide training to recruits for the cavalry and yeomanry regiments. Only four of them saw any combat—the 6th, 8th, 9th, and 10th Reserve Cavalry Regiments—all during the 1916 Easter Rising in Dublin.McNally 2007, pp.26 87 The 6th Reserve Cavalry Regiment, with 35 officers and 851 other ranks, was the largest unit then available to Dublin commander Brigadier General William Lowe of the 7th Dragoon Guards.Byrne 2007, p.104

Commanders

The cavalry were well represented among the British Army's higher ranks, with five of the ten officers who would command the five armies on the Western Front being cavalrymen.Griffith 1998, p.142 The two commanders of the BEF during the First World War, Field Marshals John French and Douglas Haig, came from the 19th Hussars and 7th Hussars respectively.Pearce and Stewart 2002, pp.289–290Griffiths and Greiss 2003, p.69 William Robertson, 3rd Dragoon Guards, who rose in rank from private to field marshal,Holmes 2005, p.121 was the Quartermaster General, then Chief of Staff of the BEF before becoming the Chief of the Imperial General Staff in December 1915.