Buller proclaimed his intention of attacking Botha by a preliminary bombardment of the Colenso kopjes on December 13 and 14; but the burghers lay low and gave so little indication of their presence that it almost seemed that they had abandoned the line of the Tugela.  The British Army was encamped near Chieveley four miles south of Colenso.

On the evening of December 14 the scheme of attack was delivered to the Brigadiers.  The leading idea of it was a frontal attack to be delivered from the village of Colenso, where the Tugela is crossed by an iron railway bridge as well as by an iron wagon bridge.  The latter had been left intact by the enemy, possibly in order to entice the British troops across the river.  Buller appears to have been unaware how far the Boer trenches extended towards the west, and to have assumed that only the kopjes immediately opposite Colenso were occupied.  Hildyard’s Brigade was ordered to march in the direction of the “iron bridge,"[21] to cross at that point, and then to “seize the kopjes north of the iron bridge.”  The attack on the enemy’s right, which was believed to be weak, was assigned to Hart’s Irish Brigade.  He was instructed to cross the Tugela at a bridle drift about two miles west of Colenso and work down the left bank towards the occupied kopjes.  Two infantry Brigades were retained as reserves to be used when required; and the mounted Brigade was ordered to move towards Hlangwhane and occupy it, if possible, and cover the right flank; but the weakness of the Boer position on that hill, which was cut off by the river from the main line of defence, does not seem to have been realized.  A few batteries were sent with Hart, but the bulk of the artillery was ordered east of the railway to support Hildyard.

Buller’s scheme has been severely criticized ever since its failure, but Clery who was in nominal command of the Natal force, and in whose name the battle orders were issued, as well as the other general officers, acquiesced in it.  But in fact hardly any scheme could have been devised more likely to play into Botha’s hands.  Buller hoped to get a footing on the left bank and Botha hoped that he would succeed in doing so.  Botha’s special idea was to allure the troops of the frontal attack to his own side, where he could easily pound them from his kopjes and carry out his general idea of netting the British flanks.

Buller had not then been in action with the Boers and he probably underrated their tactical capacity; but already he seems to have contemplated the possibility of the loss of Ladysmith, for in his despatch of December 13 to Lord Lansdowne, in which he justified his sudden change of the plan of campaign, he said that “it would be better to lose Ladysmith than to leave Natal open to the enemy.”

Nor did the Boers enter into the contest with much confidence.  They had not yet tried Buller’s mettle and his name was to them a tradition of courage handed down from the Zulu war, in which some of the older burghers now opposing him on the Tugela had served under him.  The curious omission to inform White in Ladysmith that an attack on Colenso was to be made on December 15 may have arisen from Buller’s doubts as to its issue, or from reluctance to heliograph a message in a cipher of which the enemy might have the key.