Horse artillery was highly mobile, light artillery, used as a mobile reserve and to support cavalry. It differed from field artillery in that all its gunners were mounted. The concept was introduced by Frederick ‘the Great’, who saw it as a mobile reserve to rapidly occupy those gun positions from which effective fire could be delivered. As virtually all fire was direct—that is, the guns had to see the target—it might be necessary to move artillery continuously to exploit opportunities to hit the enemy. The guns were usually 4- or 6-pounders. The support of cavalry started as a subsidiary role, because it was found that horse artillery had similar mobility and cross-country performance to cavalry. By the time of the Napoleonic wars support of cavalry had become its principal role. At Waterloo (18 June 1815), however, Sir Augustus Frazer, commanding the eight troops, each of six guns, of horse artillery used it far more intelligently. Two troops were detached to support the cavalry brigades, because they were some way away, leaving six, four of which had been up-gunned with 9-pounders and one, most unusually, with 5½ inch howitzers. Lord Uxbridge, commanding the cavalry, agreed and ‘offered him all the horse artillery to use as he wished’.
This unit, heavier than most horse artillery, was first of all moved to strengthen the centre of Wellington's position, which had been weakened out of concern for his right flank, at about 10.30. They were then moved to the right to strengthen that flank, at noon, then forward to help repel French cavalry charges at 15.30. Two troops ‘advanced with an alacrity and rapidity most admirable’; Wellington exclaimed, ‘that is how I like to see horse artillery move’. Finally, at 19.30, the troop on the left flank, which was unemployed, was moved into the centre to help retake La Haye Sainte as the victorious Allies counter-attacked.
Horse artillery played an important part in the fighting in India, but as ordnance generally became heavier its importance declined and the advent of indirect fire removed one of the reasons for its existence: to get to places where it could see the enemy. Because of its fast movement and association with the cavalry, the ‘horse artillery’ acquired a certain social status and glamour. It had different, cavalry-style uniforms and, in the Royal Artillery, ‘ball buttons’ as opposed to the common, flat kind. After its battlefield function had been subsumed by increasingly mobile field artillery, the title was retained for certain units within the Royal Artillery as a kind of élite. It was historically appropriate for self-propelled (SP) guns, designed to keep up with and support armour, and in the 1970s 1st Regiment RHA (Royal Horse Artillery) operated SP guns while 3 RHA was given anti-armour guided missiles. The 7 RHA was the parachute artillery regiment, which supported the airborne brigade, armed with light pack howitzers, which could be dropped by parachute, along with the parachute-trained gunners. The Royal Artillery also maintained a mounted troop—the King's Troop—to gallop into position and fire ceremonial salutes using immaculately maintained 13-pounders of WW I vintage. With its guns on parade the Royal Horse Artillery takes precedence over all other units in the British army, including the Household Cavalry.
— Christopher Bellamy
