Crimean War
In April 1854 Colonel Scarlett was appointed Brigadier-General of the Heavy Brigade of Cavalry, under Lord Lucan, Commander of the Cavalry Division. The 5th Dragoon Guards formed part of Scarlett's Heavy Brigade which was sent to the Black Sea in 1854. There it suffered heavily from cholera in the camps of Varna.
During the Battle of Balaclava on the morning of 25 October 1854, the Russians had stormed a series of hills known as the Causeway Heights beyond which lay the "Valley of Death" where the Earl of Cardigan would lead the Light Brigade in one of the great military blunders of the nineteenth century.
Lord Raglan ordered Scarlett to move eight squadrons of his brigade back to Kadikoi, to support the 93rd Highlanders defence of the British base at Balaklava. As Scarlett led his column of the Heavy Brigade across the sprawling tented camp of the Light Brigade, a Russian cavalry force of approximately 2000 was spotted just 800 yards from their left flank, at the top of the heights.
The 55-year-old Scarlett quickly assembled just 300 of his Inniskillings and Scots Greys at the foot of the heights, organising them into parade-perfect formation, and sounded the charge. As onlookers watched from the rear, Scarlett led his red-clad "Heavies" into the centre of the grey mass of Russians. His attack was soon followed by rest of the column (the remainder of the Inniskillings and the 4th, and 5th Dragoon Guards). Even the two squadrons of 1st Royal Dragoons who had remained behind to hold the Brigade's original position attacked on their own initiative. This action became known as the Charge of the Heavy Brigade and caused the enemy formation to collapse completely. The Russians were routed and retreated across the heights into the valley that would soon be the scene of the Light Brigade charge. Although successful, it defied military doctrine of the time, as the Russians were more numerous and, more importantly, the charge was made uphill against an oncoming force.
Cardigan had observed the action with his "Lights" from a short distance away, and had he used his initiative and chosen this moment to finish what Scarlett had started, the Charge of the Light Brigade might well have been remembered as a success. Later when Cardigan finally led his men into the valley, the Earl of Lucan, Scarlett and the Heavies waited in reserve. Scarlett had started to advance in the hope of salvaging something from the disaster when Lucan, fearing the complete loss of the Light Brigade, sounded the retreat.