The Battle of Dunkirk was a battle in the Second World War between the Allies and Germany. A part of the Battle of France on the Western Front, the Battle of Dunkirk was the defence and evacuation of British and allied forces in Europe from 24 May to 4 June 1940.
After the Phoney War, the Battle of France began in earnest on 10 May 1940. To the east, the German Army Group B invaded and subdued the Netherlands and advanced westwards through Belgium. In response, the Supreme Allied Commander French General Maurice Gamelin initiated "Plan D" which relied heavily on the Maginot Line fortifications. Gamelin committed the forces under his command, three mechanised armies, the French First and Seventh and the British Expeditionary Force (BEF) to the River Dyle. On 14 May, German Army Group A burst through the Ardennes and advanced rapidly to the west toward Sedan, then turned northwards to the English Channel, in what Generalfeldmarschall Erich von Manstein called the "sickle cut" (known as "Plan Yellow" or the Manstein Plan), effectively flanking the Allied forces.
A series of Allied counter-attacks, including the Battle of Arras, failed to sever the German spearhead, which reached the coast on 20 May, separating the British Expeditionary Force (BEF) near Armentières, the French First Army, and the Belgian Army further to the north from the majority of French troops south of the German penetration. After reaching the Channel, the Germans swung north along the coast, threatening to capture the ports and trap the British and French forces before they could evacuate to Britain.
In one of the most widely-debated decisions of the war, Adolf Hitler ordered his generals to halt for three days, in a successful effort to maintain control over them, giving the Allies time to organise an evacuation and build a defensive line. Despite the Allies' gloomy estimates of the situation, in the end, over 330,000 Allied troops were rescued.