In the chaos, the commandos which De Wet had arranged should break out remained in the trap and simplified Hunter's task. In succession, Retief's Nek, Slabbert's Nek, and Commando Nek were taken, the latter by Rundle, who on July 28 joined Hunter at Fouriesburg. Witnek had been abandoned by the Boers, who now had only Naauwpoort Nek and the scarcely practicable Golden Gate open to them.
The Nek was closed by Hunter on July 27, and a position outside the Golden Gate, but not the Gate itself, was occupied. The greater part of the Boer force was now practically sealed up in the Basin.
A Council of War was held to elect a new chief commandant. Had the vote been taken ten days earlier the situation might possibly have been saved, but the belated proceedings which displayed the weakness of a democratically organized army, and which, in the absence of representatives of the commandos not on the spot, were of doubtful validity, only added to the existing confusion. Prinsloo, however, seems to have been informally chosen.
His first act was to endeavour to obtain an armistice from Hunter, who naturally refused it. A few hours later Prinsloo agreed to surrender, and on July 30 the main body of the Boers in the Basin laid down their arms at Slapkranz. Roux, the rival candidate for the Chief Command, protested against the surrender, not only to Prinsloo, but also in person to Hunter, to whom he pleaded, that as Prinsloo had not been duly elected, the act was unauthorized and therefore was not binding on him. Hunter refused to listen to such quibbles. On several occasions during the war the Boers had profited by the honourable reluctance of the British commanders to repudiate an unauthorized raising of the white flag, lest they should be accused of having laid a trap to lure on the enemy. Hunter rightly held that Roux's plea for local option was inadmissible, and that the surrender must apply to the whole force. Roux then yielded.
A large number of burghers, however, as soon as they heard that Prinsloo had agreed to surrender, hurried away under Haasbroek, and scraped through the Golden Gate and joined Olivier and Hattingh outside the Basin. They were successful in evading the capitulation, for Olivier, when informed of it officially under a flag of truce, also declined to be bound by Prinsloo's act, and Hunter was unable to insist upon it. He trekked away towards Harrismith unmolested by the troops watching the Golden Gate, and he baffled for four weeks the columns sent in pursuit by Hunter, who, however, prevented him joining De Wet. He was taken prisoner near Winburg on August 27.
The tangible result of the Brandwater Basin operations was the capture of more than 4,000 Boers and of three guns, two of which had been lost at Sannah's Post. The mountains in which the burghers had taken refuge became a prison, from which they were taken when Hunter came on circuit for the gaol delivery, and on conviction they were sent beyond the seas.
Yet subsequent events showed that Lord Roberts would have made a good bargain if he could have exchanged all the burghers and the guns, and all the loot of horses, cattle, and sheep, for one man who had slipped through Slabbert's Nek on July 15, 1900.