By the beginning of February 1902 the lines of blockhouses in the north eastern Free State were complete. Early in February 1902 the new system of sweeping using the newly-encompassing blockhouse lines to the maximum was attempted. Up until then the Boers had been able to pass the British lines when night fell and gaps in the line opened up as the troops bivouacked. With the blockhouse lines now complete and reinforced for the occasion of a drive, the mounted troops would now form a continuous line ninety kilometres in length. The flanks would be on a blockhouse line and the horsemen would maintain the line riding straight ahead by day. At night every officer and every man would be on picquet duty in a continuous entrenched line of picquets. In theory in this way there would be no holes in the net and every Boer commando would be hedged in by the line of horsemen, the blockhouses with their wire entanglements and armoured trains on the railway lines. To maintain such a line over broken country with hills and rivers to be crossed required discipline and skill, not to mention endurance since the drives covered fifteen to twenty kilometres per day for a week or more.