1940 May 27th.-June 4th.

The Dunkirk evacuation, code-named Operation Dynamo, also known as the Miracle of Dunkirk, was the evacuation of Allied soldiers from the beaches and harbour of Dunkirk, France, between 27 May and 4 June 1940. The operation became necessary when large numbers of British, French, and Belgian troops were cut off and surrounded by the German army during the Battle of France in the Second World War. In a speech to the House of Commons, British Prime Minister Winston Churchill called the events in France "a colossal military disaster", saying that "the whole root and core and brain of the British Army" had been stranded at Dunkirk and seemed about to perish or be captured.

In his We shall fight on the beaches speech on 4 June, he hailed their rescue as a "miracle of deliverance".

After the Soviet Union and Nazi Germany invaded Poland in September 1939, marking the beginning of the Second World War, the British Expeditionary Force (BEF) was sent to aid in the defence of France. Germany invaded Belgium and the Netherlands on 10 May 1940, and three of their Panzer corps attacked France through the Ardennes and rapidly drove to the English Channel. By 21 May, the German forces had trapped the BEF, the remains of the Belgian forces, and three Frencharmies in an area along the northern coast of France. Commander of the BEF General John Vereker, 6th Viscount Gort immediately saw that evacuation across the Channel was the best course of action, and began planning a withdrawal to Dunkirk, the closest location with good port facilities. 

A controversial Halt Order was issued with Nazi dictator Adolf Hitler's approval 22 May. This gave the trapped Allied forces time to construct defensive works and pull back large numbers of troops toward Dunkirk. From 28–31 May 1940, in the Siege of Lille, the remaining 40,000 men of the once-formidable French First Army fought a delaying action against seven German divisions, including three armoured divisions.

On the first day of the evacuation, only 7,669 men were evacuated, but by the ninth day a total of 338,226 soldiers had been rescued by a hastily-assembled fleet of over 800 boats. Many of the troops were able to embark from the harbour's protective mole onto 39 British destroyersand other large ships, while others had to wade out from the beaches, waiting for hours in the shoulder-deep water. Some were ferried from the beaches to the larger ships by the famous little ships of Dunkirk, a flotilla of hundreds of merchant marine boats, fishing boats,pleasure craft, and lifeboats called into service for the emergency. The BEF lost 68,000 soldiers during the French campaign and had to abandon nearly all of their tanks, vehicles, and other equipment. In his speech to the House of Commons on 4 JuneChurchill reminded the country that "we must be very careful not to assign to this deliverance the attributes of a victory. Wars are not won by evacuations." The events at Dunkirk remain a prominent folk memory in the United Kingdom.