On the 23rd Hunter's force was held by the Boers at the strong pass of Retief's Nek, but on the 24th they were compelled to abandon it, as the capture of Slabbert's Nek by Clements threatened their rear. This latter pass was fortified most elaborately. It was attacked upon the 23rd by Brabant's Horse and the Royal Irish without success. Later in the day two companies of the Wiltshire Regiment were also brought to a standstill, but retained a position until nightfall within stone-throw of the Boer lines, though a single company had lost 17 killed and wounded. Part of the Royal Irish remained also close to the enemy's trenches. Under cover of darkness, Clements sent four companies of the Royal Irish and two of the Wiltshires under Colonel Guinness to make a flanking movement along the crest of the heights. These six companies completely surprised the enemy, and caused them to hurriedly evacuate the position. Their night march was performed under great difficulties, the men crawling on hands and knees along a rocky path with a drop of 400 feet upon one side. But their exertions were greatly rewarded. Upon the success of their turning movement depended the fall of Slabbert's Nek. Retief's Nek was untenable if we held Slabbert's Nek, and if both were in our hands the retreat of Prinsloo was cut off.
At every opening of the hills the British guns were thundering, and the heads of British columns were appearing on every height. The Highland Brigade had fairly established themselves over the Boer position, though not without hard fighting, in which a hundred men of the Highland Light Infantry had been killed and wounded. The Seaforths and the Sussex had also gripped the positions in front of them, and taken some punishment in doing so. The outworks of the great mountain fortress were all taken, and on July 26th the British columns were converging on Fouriesburg, while Naauwpoort on the line of retreat was held by Macdonald. It was only a matter of time now with the Boers.
On the 28th Clements was still advancing, and contracting still further the space which was occupied by our stubborn foe. He found himself faced by the stiff position of Slaapkrantz, and a hot little action was needed before the Boers could be dislodged. The fighting fell upon Brabant's Horse, the Royal Irish, and the Wiltshires. Three companies of the latter seized a farm upon the enemy's left, but lost ten men in doing so, while their gallant colonel, Carter, was severely wounded in two places. The Wiltshires, who were excellently handled by Captain Bolton, held on to the farm and were reinforced there by a handful of the Scots Guards. In the night the position was abandoned by the Boers, and the advance swept onwards. On all sides the pressure was becoming unendurable. The burghers in the valley below could see all day the twinkle of British heliographs from every hill, while at night the constant flash of signals told of the sleepless vigilance which hemmed them in. Upon July 29th, Prinsloo sent in a request for an armistice, which was refused. Later in the day he despatched a messenger with the white flag to Hunter, with an announcement of his unconditional surrender.
On July 30th the motley army which had held the British off so long emerged from among the mountains. But it soon became evident that in speaking for all Prinsloo had gone beyond his powers. Discipline was low and individualism high in the Boer army. Every man might repudiate the decision of his commandant, as every man might repudiate the white flag of his comrade. On the first day no more than eleven hundred men of the Ficksburg and Ladybrand commandos, with fifteen hundred horses and two guns, were surrendered. next day seven hundred and fifty more men came in with eight hundred horses, and by August 6th the total of the prisoners had mounted to four thousand one hundred and fifty with three guns, two of which were our own. But Olivier, with fifteen hundred men and several guns, broke away from the captured force and escaped through the hills.