Early 1918 was taken up by a reorganisation but by the beginning of March, it was certain that a big German offensive was underway and that it would be soon. An intense enemy bombardment starting at 4am on 21st March signalled the enemy offensive.
The London Irish were in the La Vacquerie sector, south west of Cambrai and about two miles south of the most forward point of the Flesquieres salient. The main assaults of the German spring offensive were north and south of this salient but the danger lay in being outflanked. Some enemy patrols advancing under a smokescreen were driven off by the London Irish, but during the night, our flank divisions were overrun and orders were received to withdraw to a prearranged position, Highland Ridge. As soon as dusk fell on the 22nd March, the enemy attacked from Villiers Plouich. The London Irish stood firm and beat off four attacks by rifle and machine gun fire, finally charging the attacking party and annihilating it except for seven Germans brought in as prisoners. The Ridge later became untenable and a slow fighting withdrawal followed. Each successive position to which the battalion had been ordered to withdraw was organised with a view to defence but as the artillery was continually on the move, no support firing programme could be arranged.
The London Irish with the Civil Service Rifles (15th London Regiment) made a stand near Neuville, protecting the withdrawal of the 140th and 142nd Brigades and the fighting was desperate. The withdrawal continued through Les Mesnil, Le Transloy, Norval and High Wood (recalling the battle honours for October 1916) to Bazentin, reached on 26th March but the London Irish returned to the defence line on April 1st in support. The battalion had lost severely during the retreat. On the first day, 21st March, Lieut Millar and 52 other ranks were killed and in the following days, a further 50 other ranks died. The German offensive was not yet over. It began over on April 5th and the battalion were in action on the April 7th, being relieved on the next day, as the enemy advance petered out.