By the twenty-fourth of May, nineteen forty, the best armies in western Europe had been pushed into a shrinking pocket on the coast of France, and the pocket was still shrinking.
The town in the middle of it was called Dunkirk. It is a port, and the beaches on either side of it run for miles, flat and pale and very wide, the kind of beach where the tide goes out so far that you lose sight of the water.
Across the Channel, forty miles away on a clear day, was England. You could not see it, but every man on that beach knew exactly where it was.
There were something like four hundred thousand of them. They had no ships.
At Dover, on the English side, there is a line of white chalk cliffs, and inside the cliffs there are tunnels. They had been dug more than a century earlier, during an entirely different war, and by nineteen forty they were being used as a naval headquarters.
One of the rooms down there had once housed an electrical generator. People still called it the dynamo room.
On the evening of the twenty-sixth of May, a vice admiral named Bertram Ramsay stood in that room and gave the order to begin. The operation took its name from the room, which is why the rescue of the British army is called Operation Dynamo. There is no deeper meaning. Somebody needed a codeword and looked around.
Ramsay knew exactly what he had. He had destroyers, and he had ferries, and he had a rough idea of how many trips each could make before the Germans closed the port. The Admiralty estimate was that two days of operations might bring home forty-five thousand men.
Forty-five thousand out of four hundred thousand. Everybody in that room understood what the other number meant, and nobody said it out loud.
And then something happened that historians have been arguing about ever since.
German tanks were within about fifteen miles of Dunkirk, closer to the town than most of the British troops were, and there was very little in front of them. On the twenty-fourth of May, they were ordered to halt.
They sat still for the better part of three days.
Nobody is completely sure why. Several explanations get offered, and they may all be partly true at once. The ground in front of Dunkirk is criss-crossed with canals and drainage ditches and is genuinely bad country for tanks. The armoured divisions had been driving flat out for two weeks and were worn down, with a real number of vehicles needing repair before the next battle, which everybody assumed would be for Paris. And the head of the German air force had assured Hitler that aircraft alone could finish the job, which was the sort of promise he liked making.
Whatever the reason, the halt gave the British three days. They used them to throw a defensive line around the port and to start moving men.
Ramsay needed something the navy did not have, which was a very large number of boats that could get close to a very flat beach.
So the Admiralty put out a call for private vessels between roughly thirty and a hundred feet long, and boats began leaving harbours all down the south and east coast of England.
They were fishing boats, pleasure yachts, ferries, lifeboats, tugs, cockle boats from the Thames estuary, and at least one barge that normally hauled rubbish. Some of them were sailed by their owners, and some were requisitioned and crewed by naval ratings while the owner stood on the quay and watched his boat go. Somewhere between seven hundred and a thousand of them made the crossing, and the exact number will never be known, because there was no time to write anything down.
The sea they were crossing had mines in it and aircraft above it. But they could do the one thing a destroyer could not.
Dunkirk beach shelves so gently that a warship has to anchor a long way out. A soldier trying to reach it must wade, and then swim, and men in boots and equipment do not swim. A small boat with a shallow draught could run right up to where the men were standing, take a load, ferry it out to the big ships, and turn around and come back.
Back and forth. All day. All night. And again.
The thing that actually saved the operation, though, was not a boat at all. It was a wall.
Dunkirk harbour had two breakwaters, and the eastern one was a narrow wooden and concrete structure running about a mile out to sea. It was built to break waves. It was never meant for ships to tie up against, and it was so narrow that men could only walk along it a few abreast.
But it reached deep water.
Somebody suggested trying to bring a destroyer alongside it. It worked. From then on, men queued along that mile of walkway, in single file and in pairs, hour after hour, and stepped off the end onto warships.
There was no cover on it whatsoever. When aircraft came over, the queue lay down flat, and when it was over, the queue stood up and carried on walking. Over nine days, something like two thirds of everyone rescued left by that one narrow strip of concrete.
The men waiting on the beaches, meanwhile, stood in the water. Photographs show queues running out from the sand into the sea, men standing chest deep, holding their rifles above the waves, waiting hours for their turn.
Operation Dynamo ended on the fourth of June.
The estimate had been forty-five thousand. The final figure was three hundred and thirty-eight thousand, two hundred and twenty-six men. About a hundred and twenty thousand of them were French.
The cost was real. Almost every piece of heavy equipment the British army owned was left standing on that beach: tanks, artillery, lorries, all of it abandoned in rows and rendered useless. Hundreds of vessels were sunk, including a good many of the small ones that never came home. And several thousand French soldiers held the perimeter to the last, buying days for the men behind them, and were taken prisoner when it ended.
On the fourth of June, Churchill spoke to Parliament. He began with a sentence that people do not expect: he said that wars are not won by evacuations.
Then he said the other thing, the part everybody knows, about fighting on the beaches and on the landing grounds and in the fields and in the streets, and never surrendering.
Militarily this was a defeat. An army had been chased off a continent and had left its equipment behind. But the men came back. Guns can be rebuilt in a year. Trained soldiers cannot, and those three hundred thousand became the core of every army Britain put into the field for the next five years.
The most persistent myth about Dunkirk is that a fleet of little fishing boats carried the army home across the Channel. They did not. The overwhelming majority of men were taken off by naval destroyers and large transports, and most of those left from the mole. The little ships were the ferry service between the beach and the fleet.
That is not a smaller job. Without that ferry, the men standing in the water could not have reached the ships at all. But it is a different job, and it is worth knowing which one it was.
The English language picked up a phrase from all this. The Dunkirk spirit means a group of ordinary people, in a bad situation, each doing the one small thing they are able to do, and the small things adding up to something none of them could have managed alone.
Here is something to think about tonight. Churchill could have stood up in Parliament and simply celebrated. Instead his first sentence was a warning that this was not a victory. Why do you think he did that, on the one day when everybody desperately wanted to be told good news?