After the success of the Allies at the battles of Marne and Aisne which thwarted the Germans' intentions to capture Paris, the BEF was redeployed north to the Ypres area and in its wake followed the formations FPOs. The upheaval to the postal lines of communication caused by the retreat and re-deployment highlighted the inadequacies of dependency on the supply system for the movement of mail therefore in November the APS obtained lorries to transport mail between the railheads and set in motion what was to become a very efficient cross-post service.