He was still haunted by the troubles of the Tugela, and was unable to nerve himself for the risks that every leader must run. The Boers bewildered him. He could plan no scheme without a conviction that somehow their "knavish tricks" would frustrate it, and his inactivity made him more prone than ever to brood over possible mischances. He remained in Ladysmith because it was the only course open to him after he had by a process of elimination considered and rejected all the alternatives. Each of them had its disadvantages and its dangers, therefore it were better to stay where he was. During a critical period the Natal Army was of as little use to Lord Roberts as were the Spanish contingents to Wellington in the Peninsula; and its laggard action retarded the progress of the war. Lord Roberts laid his plans for the advance on the assumption that it would be in operation on his right flank when he reached Pretoria, and if L. Botha had found it pressing on him when he was playing at peace-making in June, instead of engaged in equally fruitless negotiations with his brother 180 miles away at Laing's Nek, it is improbable that he would have continued the struggle. On May 2 Lord Roberts informed Buller that he was ready to start from Bloemfontein, and that he expected the Natal Army to co-operate with him by attacking the Boers on the Biggarsberg, and then advancing towards the Transvaal. For this movement Buller considered that his force, which consisted of three divisions of infantry and three brigades of mounted troops, in all about 45,000 men, was insufficient; but he proceeded to carry it out. The Boers were in occupation of the whole line of the Biggarsberg from Helpmakaar westwards, and commanded the roads as well as the railway running through the range. Buller on this occasion determined rightly upon a turning movement. All his previous attacks had either been frontal or had been made so by the enemy. His plan was to move eastwards with the IInd Division under Clery, while the Vth Division under Hildyard, who succeeded Warren when the latter was called away to Bechuanaland, advanced up the railway against the Boer centre. The IVth Division under Lyttelton, composed of the infantry which had been in Ladysmith during the siege, was kept in reserve pending the development of the turning movement, which began on May 11, and was skilfully conducted by Buller and was entirely successful. Places and rivers which had not been named in the chronicle of the war since October of the previous year now emerged from their obscurity. Elandslaagte became the fulcrum of an aggressive operation. Sunday's River and the Waschbank River after an interval of seven months were again crossed by British troops, not, like Yule's force, in hasty retreat, but in confident advance.