Lord Roberts' position at Bloemfontein, and on the line of communication, had never been seriously endangered. The brilliant affairs of Sannah's Post and Mostert's Hoek were no doubt annoying to the British Army and encouraging to the enemy. At home the importance of them was greatly exaggerated. If the advance on the Transvaal was delayed by them and the subsequent operations arising out of the siege of Wepener, more time was given to prepare for it; and the British Army was usefully informed of a fact which hitherto had hardly been suspected, namely, that the enemy derived much of his power from mobility, resourcefulness, and aptitude for _guerilla_. Lord Roberts' plan for the movement on the Transvaal was an advance in line, on a front which extended from Ladysmith to Kimberley. It soon became an echelon owing to the slow movements of Buller in Natal. In the centre at Bloemfontein were the troops under the immediate orders of the Commander-in-Chief; on the left at Kimberley were Methuen, and Hunter with the Xth Division which had been brought round from Ladysmith. Between the centre and the right the intervention of Basutoland and the Drakensberg prevented the effective co-operation of the Natal Army with Lord Roberts; and a portion of the interval was occupied by the enemy. The centre columns under Lord Roberts were about 43,000 strong. Hunter and Methuen in the west had each under his command about 10,000 troops, while Buller's force, which was much nearer to the Transvaal objective than the centre, and which was still lingering on the banks of the Klip River two months after the relief of Ladysmith, numbered about 45,000. Ian Hamilton, who had done so well in the Elandslaagte and Caesar's Camp affairs, was not allowed to waste himself in the Natal lethargy. He was recalled from Ladysmith, and after taking part from the Bloemfontein side in the Wepener operations, was given command of a column which was sent on, a few days before the general movement, in the direction of Winburg to protect the right flank of the central advance and to fend off from it the hovering Boer commandos which had been pressed northwards by the April operations. He started from Thabanchu on April 30 and was soon in action with the Boer force a Houtnek under P. Botha. The battle lasted until nightfall and was renewed next day, when, with the help of reinforcements from French and Colvile, Ian Hamilton forced the Boers to retire on Clocolan.