The Battle of France had begun in earnest the previous month when the Germans swept through Western Europe using their Blitzkrieg tactics.
Within weeks the French and British armies were encircled and trapped on the beaches around the port of Dunkirk. The UK troops were made up of the British Expeditionary Force – highly trained soldiers whose loss would have proved catastrophic.
But they were sitting targets and Hermann Göering, commander of the Luftwaffe, sought permission from Hitler to move in for the kill. The situation was so desperate that there was even talk in England of discussing a conditional surrender to Germany.
But, for reasons never fully explained, a "Halt Order" was issued by the German High Command. There were sporadic attacks on the Allied troops by German fighter and bomber planes but a full-scale attack was not launched. Panzer tank crews awaited the order from Hitler but it was not until three days later that the Führer rescinded the "Halt Order."
In his memoirs, Field Marshall Gerd von Rundstedt, the German commander-in-chief in France, described Hitler’s failure to order a full-scale attack on the troops at Dunkirk as his first fatal mistake of the war.
The three-day breathing space gave the Royal Navy time to press ahead with a massive evacuation. The beach at Dunkirk was formed by a shallow slope, excluding large vessels, so the call had gone out in England for small boats to go in and pick up troops.
From 26 May until 4 June, about 800 small craft transferred soldiers to larger boats which then brought them the 46 miles back to Britain.
The smallest to make the journey across the Channel was an 18-foot open-topped fishing boat now on display at the Imperial War Museum in London.
The last of the British soldiers left on 3 June but Churchill ordered the Royal Navy to return on 4 June to rescue as many of the French rearguard as possible. They had held the line at Dunkirk while the last remaining British troops were evacuated despite facing artillery fire accompanied by strafing and bombing by German planes.
Altogether, about 338,000 men were rescued in the Dunkirk evacuation, including 123,000 French soldiers – 26,000 French on that final day.
There was jubilation and celebration in Britain and the Dean of St Paul's Cathedral described the operation as a miracle. But in the House of Commons Winston Churchill delivered sobering words: "We must be very careful," he said, "not to assign this deliverance the attributes of a victory. Wars are not won by evacuations."
But he went on to roar defiance in one of his most famous speeches:
"We shall not flag or fail. We shall go on to the end. We shall fight in France, we shall fight on the seas and oceans, we shall fight with growing confidence and growing strength in the air.
"We shall defend our island, whatever the cost may be. We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender."
Although ignoring the huge contribution made by the French, the 2017 Oscar-winning film Dunkirk, directed by Christopher Nolan, dramatises the events.
Published: May 13, 2018
Gerd von Rundstedt
Soldier, Author and British Prime Minister