 The nominal annexation of the Orange Free State and Transvaal Republic in May and September did not resolve the war . Instead , the Boer commandos transitioned to guerrilla warfare and resisted the British until 1902 . The King 's concentrated in the Eastern Transvaal , where Boers under Botha and Viljoen operated . Detachments occupied networks of blockhouses and provided complements for armoured trains . One such detachment was overwhelmed at Helvetia on 29 December . Situated near the Lydenburg – <unk> railway , Helvetia was garrisoned primarily by a contingent of the King 's equipped with a 4 @.@ 7 @-@ in gun nicknamed " Lady Roberts " . The nocturnal attack , conducted in fog , yielded considerable success for the Boers with scores of prisoners taken and the gun captured . Only King 's Kopje withstood the attack . The circumstances were controversial and a general court @-@ martial later sentenced Major Stapleton Cotton , who ordered the surrender , to be cashiered and dismissed from the army . Author Arthur Conan Doyle publicly questioned the decision and contended that the wounds Major Cotton sustained merited " some revision " of the officer 's sentence . 
