On 10 May 1940, Nazi Germany invaded France and the Low Countries, rapidly defeating the Dutch and Belgians, while armoured units attacking through the Ardennes cut off the Franco-British strike force in Belgium. By the end of May, the British and French northern armies were trapped in a series of pockets, including Dunkirk, Calais, Boulogne, Saint-Valery-en-Caux and Lille. The Dunkirk evacuation was only made possible by the resistance of these troops, particularly the French army divisions at Lille.
On 10 May 1940, Nazi Germany invaded France and the Low Countries rapidly defeating the ,Dutch and Belgians, while armoured units attacking through the Ardennes cut off the Franco-British strike force in Belgium. By the end of May, the British and French northern armies were trapped in a series of pockets, including Dunkirk, Calais, Boulogne, Saint-Valery-en-Caux and Lille. The Dunkirk evacuation was only made possible by the resistance of these troops, particularly the French army divisions at Lille.