Today’s post is written by Dr. Greg Bradsher, Senior Archivist at the National Archives at College Park.
During early May 1940, British, French, Dutch, and Belgian forces were fighting to stem the German advances, which had begun May 10, into France, Belgium, and the Netherlands. During May 11, much of the Dutch Army was put out of action and four days later it surrendered. By May 18, the German Panzer divisions, having regrouped round Saint-Quentin, instead of heading in the direction of Paris, started to swing north towards the Channel. They reached the coast at Noyelles, near Abbeville, on May 20, and soon took Boulogne and Calais. At the former city, the Royal Navy was able to evacuate at least 1,400 soldiers, before the city surrendered; the Germans capturing 5,000 Allied troops, the majority of whom were French.
The British on May 19 begin considering the evacuation of the British Expeditionary Force (BEF) from mainland Europe, and Vice Admiral B. H. Ramsay, Flag Officer Dover, was put in charge of the transport for Operation Dynamo, the code name given the evacuation. On May 21, following an unsuccessful BEF counterattack, and with dwindling supplies and the imminent collapse of the Belgian forces, the French First Army and four British divisions moved back to Dunkirk, a northern French seaport close to the Belgian frontier. On May 23, because of the British retreat from Arras, a planned counteroffensive was postponed. That day British generals in France came to the conclusion that an evacuation by sea was probably going to be necessary.