When the advance of the British forces came within striking distance of Pretoria, Lord Roberts found it necessary to have the line cut just east of the town in order to prevent the retreat towards Middleburg by rail. Burnham started to do it, taking with him a small patrol of men for assistance. They made a wide detour to avoid meeting any of the commandoes, which were now moving in the same direction. All went well with him until he had gone half way around and was about to turn to the north to find the culvert which he intended to destroy, when he suddenly met a large commando coming directly towards his party. A running fight followed, in which his horse was hit, throwing him heavily, and he was seriously injured. The rest of the party escaped, but he was made a prisoner, and not being able to walk, he was put into a wagon under a guard of four men, two riding in front and two behind. The vehicle was one of the large trek-wagons, drawn by a span of sixteen oxen and driven by a Kaffir boy, who divided his time between the front seat of the wagon and walking beside the span. Major Burnham had made up his mind to escape at all hazards, and so until night he lay in the wagon making plans. The moon was almost full, and the night was so bright that the difficulties of an attempt to escape were greatly increased. During the early part of the night the Kaffir driver kept his position on the front seat, thus preventing any experiments by the captive. He was just considering an attack on the black boy when something went wrong with one of the leaders, and the boy jumped down to remedy it. Seizing the opportunity thus afforded, Major Burnham climbed out over the seat, down on the disselboom or tongue of the wagon, on which he stretched himself flat between the oxen of the first span, swung himself under the disselboom, dropped into the road, and allowed the wagon to pass over his body. As soon as it had passed he rolled quickly over and over into the ditch, and lay perfectly quiet while the rear guard passed by, wholly unconscious that their prisoner had escaped. The khaki uniform which Major Burnham wore made this little bit of strategy possible, for had he been in dark clothes his body would probably have been seen by the guard, who rode along within twenty-five feet of him.