Nazi Germany began its attack on Western Europe on May 10, 1940. England, France, Billy at the time

At that time, the Netherlands and Luxembourg had 147 divisions and more than 3 million troops, which were comparable to the strength of Germany. However, the French were strategically rigid and conservative, and were slow to mobilize, pinning their hopes on what they considered to be the Maginot Line, and declaring no war on Germany. On the German-French border, there were only small-scale mutual fires, no major battles were fought, and the famous "strange war" in history appeared.

However, the Germans did not attack the Maginot Line, they attacked Belgium, the Netherlands, and Luxembourg first, and crossed the river from Sedan into France, bypassing the Maginot Line. The iron heel of the German fascists soon set foot in the Netherlands, Belgium, and Luxembourg.

On May 21, 1940, the Germans approached the English Channel, besieging nearly 400,000 Anglo-French troops in a narrow strip of northern France, leaving only Dunkirk, a small port of 10,000 inhabitants, as a sea retreat.

The situation is critical, and the port of Dunkirk is a highly vulnerable target to constant bomber and artillery fire. If 400,000 people retreated from this port, under the heavy fire of German artillery, the consequences would be unimaginable.

The British** and the Navy mobilized large numbers of crews to mobilize the people to come to the rescue of the army. Their plan was to try to evacuate 30,000 people. In such a dangerous situation, this motley fleet rescued 336,000 people in about a week.

In the early hours of September 1, 1939, the German army launched an attack on Poland, and World War II broke out. On 3 September, Britain and France declared war on Germany over their interests. But in reality, the Anglo-French forces only hid behind the Maginot Line, and did not provide effective military support to Poland. On September 27, the Germans occupied Warsaw and Poland fell completely. In the meantime, Britain and France condemned Germany only diplomatically. This period was called "fake war", "sit-down war" or "strange war" by the Germans.

In the early morning of May 10, 1940, 136 divisions of the German army, guided by more than 3,000 tanks, bypassed the Maginot Line and attacked Belgium, the Netherlands, France, Luxembourg and other countries with two army groups A and B. The Germans were directed at Army Group A on the left flank, commanding strong armoured forces to launch an attack at the northern end of the Maginot Line, a rugged and forested Ardennes mountain that had been considered impassable for tanks. This was a great surprise to the Anglo-French forces that marched to Belgium to meet Army Group B on the right flank of the German army, and in just over ten days, the German armored forces crossed the French mainland and penetrated directly into the shores of the English Channel. The coalition forces in the north were in fact encircled in the Flemish region of northern France. On May 27, the Belgian army surrendered, and the 400,000 Anglo-French troops began to retreat to Dunkirk. The English Channel to the west became the only hope for the coalition forces.

When the German army was closing in on Dunkirk from the west, south and east, and the nearest German tank was only 10 miles from the port, on May 24, 1940, the German army received an order from Hitler himself to halt the advance. Hitler's order puzzled the generals of the German tank forces, and Guderian sighed even more. Dunkirk is at your fingertips, but you are ordered to stop advancing! And the German Air Force was on the offensive. The controversy that arose later with this order was considered by many military historians to be a stupid order for Hitler to arbitrarily interfere with military command.

In fact, Hitler's order was based on his considerations, and it could not be considered entirely his responsibility.

The first was that after the war in northern France became clear, the Germans needed to preserve their armoured forces for the next combat operation. Plus Goering assured Hitler that the Air Force could wipe out the coalition forces in Dunkirk. The terrain of Dunkirk was full of swamps and low-lying areas, which was not conducive to the advance of the armored forces, and there was no need for the armored forces to suffer losses. The German General Headquarters had planned for Army Group B to complete the final encirclement operation in a unified manner.

Second, although the piecemeal counterattacks of the coalition forces were not effective, they increased the concern of some senior German commanders about the attrition of the armored forces, because the rapidly advancing armored forces left the infantry units far behind. On the 24th, Hitler visited Army Group A Headquarters, and the war diary of the Rensted headquarters recorded that during the meeting, Rensted suggested that the Panzer Division on the canal line not far from Dunkirk should stop advancing and wait for more infantry units to respond. Hitler agreed to this suggestion and decided that the armoured forces should be preserved for use in the attack on the French forces south of the Songm River. At the same time, the commander of the Luftwaffe, Goering, assured that the air force could take on the task of destroying the coalition forces in the encirclement.

Another may also be attributed to Hitler's order, fearing that the Panzers would be trapped in the water-crisscrossed strip of Dunkirk and would not be able to quickly intercept the retreat of the British and French forces.

In addition, there are also those who believe that Hitler had a political intention to withdraw part of the British army to Britain, which would be politically helpful in peace talks with Britain. Some people, including the commanders of the front-line armored forces, objected, believing that they should move on. However, this statement is inconsistent with Hitler's Directive No. 13 issued on the 24th, in which Hitler ordered Army Group B and the Air Force to cooperate to eliminate the British, French, Belgian and Dutch forces in the encirclement as soon as possible.

As a result of the execution of this order, the Anglo-French forces retreated to Dunkirk under the pressure of the German Army Group B in front of them, while Army Group A, which had cut off their retreat, was closer to Dunkirk, but stopped the offensive in the canal area west of Dunkirk and did not gather forces to outflank the coast, which gave the Anglo-French forces an opportunity. The coalition forces were fighting for survival and strengthened their defensive positions close to Dunkirk. Although on May 27 of the same year the German armored forces resumed the offensive in order to prevent the retreat of the Anglo-French forces from Dunkirk, they were unable to break through in the face of the enemy's organized defensive line. The Anglo-French forces succeeded in delaying the German offensive and buying more time for the troops to evacuate Dunkirk. However, Guderian's recollections ("Blitzkrieg Hero") also mention that his troops did not stop attacking after the 24th, and Cales's British troops held out until 16:45 pm on the 26th before surrendering. And on that day Hitler had already ordered the resumption of the attack, so there are still many theories about how much the cessation of the order had on Army Group A.

The British Führer felt that the German army was overwhelmed, Li Ming's Flying Eagle Brigade had defeated a large number of British air force units, London could not be defended, and the British and French high-level began to discuss the retreat plan。。。。。。。 The office quarreled endlessly, some said to defend, some said to retreat, and the two sides quarreled.

As early as June 19, the British foresaw that defeat was a foregone conclusion, and the wartime cabinet instructed the Admiralty to develop a plan to organize the retreat of the expeditionary force, codenamed "Operation Dynamo". The operation, commanded by Vice Admiral Bertram Ram, commander of the port of Dover, planned to evacuate 10,000 men a day from the three ports of Calais, Buren and Dunkirk on the French coast, and to concentrate 30 ferries and 12 minesweepers. Ramsay also suggested strengthening air cover, but Admiral Hugh Dowding, commander of the British Air Force Fighter Command, said that fighter jets could only be sent to Dunkirk if they were satisfied with the defense of their homeland.

On July 20 of the same year, the main German army reached the coast of the English Channel, and about 40 divisions of the Anglo-French army were surrounded in the Dunkirk area on the Franco-Belgian border.

At this time, the Anglo-French forces were attacked on three sides in the Dunkirk area, one facing the sea, and the situation was very critical, and the only way to survive was to withdraw to Britain by sea. Fortunately, at this time, Guderian was held back on the grounds that he had not received an order, and rested for two whole days, until the 22nd, according to the order of Army Group A Command, he went north to attack the coastal ports (Guderian's "Blitzkrieg Hero"), giving the British a chance to escape from the encirclement.