The 47th (1/2nd London) Division planned to attack with two brigades, each reinforced by a battalion from the reserve brigade, along either side of the Ypres–Comines Canal. Large numbers of machine-guns were organised to fire offensive and defensive barrages and signal detachments were organised to advance with the infantry. An observation balloon was reserved for messages by signal lamp from the front line, as insurance against the failure of telephone lines and message-runners. The divisional trench mortar batteries were to bombard the German front line opposite the 142nd Brigade, where it was too close for the artillery to shell without endangering British troops. Wire-cutting began in mid-May, against considerable local retaliation by German artillery. At the end of May the two attacking brigades went to Steenvoorde to train on practice courses built to resemble the German positions, using air reconnaissance photographs to mark the positions of machine-gun posts and hidden barbed wire. Divisional intelligence summaries were used to plan the capture of German company and battalion headquarters. The 140th Brigade, with four tanks attached, was to occupy White Château and the adjacent part of , while the 142nd Brigade attacked the spoil heaps and the canal bank to the left. On 1 June, the British artillery began the intense stage of the preparatory bombardment for trench-destruction and wire cutting; the two attacking brigades assembled for the attack from 4 to 6 June.