In 2008, Harris wrote that in late September there had been legitimate grounds for thinking that the German defence of the Somme might collapse. German troops had lost morale, surrendered more willingly and suffered more casualties in September than in any other month. Air reconnaissance had revealed that the Germans were building three more defensive lines () but in front of Le Transloy, was far less formidable than the three lines overrun since July. Harris also wrote of the rain and mud and that the Germans had relieved exhausted divisions during the respite, reinforced the artillery and moved machine-guns to the rear, where they were less vulnerable but could fire through barrages at the British infantry.