Statements from Alsatian and Polish deserters, a captured flying officer and other prisoners were all pointing to the principal point of attack on the British sector would be between Arras-St.Quentin in the coming days. The troops of the British 3rd & 5th Armies were told to expect an attack on the morning of either 20th or 21st March. However for the men in the front, warnings had been issued before and nothing had happened. In light of the intelligence Haig transferred four of his divisions from the 2nd Army in the north to the 3rd & 5th Armies expected to take the brunt. The triple defence system had been established along the British line, but the sector recently taken over from the French was in the poorest condition. Moreover the Fifth Army’s sector was the widest and most lightly held. For the purposes of harassing the enemy, 700 cylinders containing gas were fired from the AIF 5th Division’s front by a special company of the Royal Engineers. The history of the 226th RIR says that 21 of its men were gassed, nine fatally.
Following the Twenty-Second 