In September 1918, during the period after the Battle of Albert whilst Third Army was advancing towards the Hindenburg Line, Haldane regularly vented in his diary about Harper's supposed shortcomings. At one point Haldane lobbied Byng (GOC Third Army) to urge Harper to make quicker progress, and when Byng pointed out that IV Corps were making progress recorded “I should “progress” by sending Harper to the rear”. Haldane was concerned that Third Army orders gave Harper (on Haldane's right, i.e. southern flank) “an excuse for not coming forward at the same time as my Corps” (22 September). Haldane appealed to Byng, who refused to overrule Harper. Haldane attributed this to their lack of experience of the NorthWest Frontier. Byng's decision was wrong and Haldane's advance was hampered by Harper's failure to seize the high ground.