The German Halt Order
Options for the location of the evacuation were running short. The Germans had cut off Calais and Boulogne. By May 25, they had captured both port towns. The only available option left to the allies was Dunkirk. As well as having excellent port facilities, marshes surrounded the town and it had old fortifications- both perfect for holding off any advancing German troops. It also had the longest beach in Europe- the ideal place for the assembling troops to wait. Dunkirk may have been the last resort. But it was a good one.
Extraordinarily, the Germans gifted the allies the time to move their troops to Dunkirk by the German decision to halt their advance. On May 24, General Rundstedt, the German commander, advised Hitler to order a halt of German ground troops. Rundstedt was concerned that the marshland around Dunkirk would mire his tanks-vehicles he could not afford to lose. So, he decided that the German army would concentrate its efforts on taking Calais, leaving the Luftwaffe, the German air force, to stop the evacuation in its tracks.
The halt gave the British and French troops time to gather at Dunkirk. The French planned to use the port as a base to continue their fight, while the British commanders planned to retreat. But the halt gave both armies time to gather and fortify the area around the port – preparations that were crucial to both purposes.
Allied troops slowly began to fight their way to Dunkirk. When the German’s noticed, they realized their error and lifted the halt on May 26. But by then, it was too late. Most troops were safely on their way to Dunkirk.