Colley climbed Majuba in the dark with around 400 men, worried the Boers were edging trenches toward the hill and meaning to seize the high ground first. He may also have hoped the mere sight of British troops looking down on the Boer camp at Laing's Nek would break their nerve. So sure was he of his position that his men dug no proper defences. The decision would prove fatal. The summit's slopes curved outward rather than inward, and a soldier kneeling at the rim could often see no more than fifty yards down. Whole stretches of the climb — up to 400 yards in places — lay in what the army grimly called "dead ground," invisible to the men at the top.

The Boers did not consider the hill scalable for war. Then they tried. Storming parties of volunteers, at least 450 strong, gathered under commanders including Nicolaas Smit, Stephanus Roos and Joachim Ferreira. Their method was patient and lethal. Older, experienced marksmen stayed low on the ridges and laid down accurate fire at 800 to 1,200 yards, where the British stood silhouetted against the morning sky, easy targets who could not safely lift their heads to look down. Under that cover, younger men climbed the dead ground, sheltering behind rock and scrub, ascending almost unseen. At 12:45 Ferreira's men poured fire onto an exposed knoll on the British right and took it, and the high ground began to change hands.

The collapse came fast. The British general Piet Joubert later noted a cruel detail: British rifles had been sighted for 400 to 600 yards, but the fighting was happening at fifty to a hundred, so the soldiers fired downhill straight over the heads of the Boers climbing toward them. As the rim fell, the saucer-shaped hollow where reserves had sheltered from long-range fire turned into a death trap — now the Boers above could fire down into it while the men below had nowhere fortified to fall back into. Retreating soldiers spilled into the basin and collided with reserves already under attack. Colley, slow to grasp the danger, finally tried a fighting retreat and was killed by Boer marksmen. The rest fled down the rear slopes under fire from the summit.

The arithmetic of the day was staggering. The British counted 285 killed, wounded or taken — among the dead, Captain Cornwallis Maude, son of a government minister — while the Boers lost barely a handful, a single man killed and a few wounded. These were not statistics to the families who waited for them; on both sides they were husbands and sons, farmers and soldiers, who climbed or held a hill in the African dawn. The defeat helped end the war within months. Under the Pretoria Convention of 1881 the Transvaal won self-government under a thin veneer of British oversight, and Britain quietly looked away from the humiliation. But it was not forgotten. "Remember Majuba" became a British rallying cry, and when the Second Boer War came in 1899, soldiers went into battle with the hill of doves still on their lips.