When the German spring offensive (Operation Michael) was launched on 21 March 1918, 63rd (RN) Division was occupying part of the Flesquières Salient, the last remaining gain from the Battle of Cambrai. This was recognised as being vulnerable, so was only held by the outpost line, the main battle zone being a shorter line further back. The Germans steadily shelled the salient with mustard gas between 10 and 16 March, possibly hoping that the British would withdraw from it anyway; by the time it was relieved 7th RF had about 250 men evacuated to hospital, but it had to go back into the line on 20/21 March. The battalion received a draft of over 100 reinforcements at 01.00 on 21 March: after a three-day journey in lorries they were sent straight up into the line in the dark, never having been in a trench before.