The operation was named after a room. Deep in the casemates beneath Dover Castle, Vice-Admiral Bertram Ramsay planned the evacuation of the British Expeditionary Force from a chamber that had once housed an electrical dynamo — hence Operation Dynamo, launched on 26 May 1940. The realistic hope, Ramsay was told, was to lift perhaps 45,000 men in the two days before the Germans closed the port. By the time the last destroyer slipped out of Dunkirk harbour before dawn on 4 June, the count stood at 338,226 — around 198,000 British and 140,000 French — and the word Dunkirk had changed its meaning in the English language.
The army was there to be rescued because the German offensive of May 1940 had done something no Allied planner believed possible: punched armoured columns through the Ardennes, crossed the Meuse at Sedan, and raced to the Channel coast in ten days, cutting the Allied armies in two. Then, on 24 May, with the panzers barely a day from Dunkirk, came the celebrated halt order — issued by Colonel General von Rundstedt and endorsed by Hitler. The reasons remain one of the war's favourite debates: the tanks needed refitting for the coming battle for France; the low, canal-cut ground suited defenders; and Göring had promised the Luftwaffe alone could finish the pocket. The romantic theory that Hitler deliberately let the British escape as a peace overture has little documentary support. Whatever the motive, the two-day pause let the Allies wire a defensive perimeter around the port.
The mole and the little ships
The enduring image is of soldiers wading from the beaches into rowing boats, but the shallow beaches were desperately slow. The evacuation was saved by an improvisation: Captain William Tennant, the senior naval officer ashore, realised ships could berth against the East Mole, a narrow breakwater of wood and concrete never built for the purpose, and roughly two-thirds of all the men lifted went from that fragile jetty. The "little ships" — around 850 of them: Thames pleasure steamers, fishing smacks, barges, lifeboats, the cockle boats of Leigh-on-Sea — mostly ferried men from the shallows out to destroyers and ferries offshore, though some ran all the way home loaded with soldiers. The smallest, the 14.7-foot fishing boat Tamzine, now sits in the Imperial War Museum. The paddle steamer Medway Queen made seven round trips and brought out roughly 7,000 men, earning the nickname "Heroine of Dunkirk". Fortune helped too: for much of the nine days the Channel stayed unusually calm, and smoke from burning oil tanks shrouded the harbour from the Luftwaffe, whose bombs often buried themselves harmlessly in soft sand before exploding.
The deliverance was not cheap. Six British and three French destroyers were sunk, with over 200 other vessels lost; the RAF lost more than 100 aircraft fighting inland, largely out of sight of the troops — who bitterly asked "Where was the RAF?" as bombs fell on the beaches. The BEF abandoned virtually all its heavy equipment: some 2,500 guns and around 65,000 vehicles were left on the far shore, along with vast stores of ammunition and fuel, leaving Britain's home army critically short of weapons through the invasion summer of 1940. Some 40,000 French soldiers of the rearguard, whose stand made the final lifts possible, marched into five years of captivity, and most of the French troops carried to England returned to France within weeks, in time for the surrender.
Deliverance, not victory
Churchill, who had braced the country for what he privately feared would be "hard and heavy tidings", met the euphoria head-on in the Commons on 4 June: "We must be very careful not to assign to this deliverance the attributes of a victory. Wars are not won by evacuations." The same speech ended with "we shall fight on the beaches" — defiance built on the army Dynamo had saved. A fortnight later the campaign's true worst day passed almost unrecorded: the liner Lancastria, evacuating troops from Saint-Nazaire on 17 June, was bombed and sank with a death toll usually estimated well above 3,000 — Britain's worst-ever maritime disaster, its reporting suppressed on Churchill's orders. "Dunkirk spirit" endures because the essential fact was real enough: the trained core of an army that should have been lost came home, and four years later it went back the short way across the Channel.
Quiz nuggets
- Operation Dynamo, 26 May to 4 June 1940, rescued 338,226 men against an initial hope of about 45,000.
- The operation was planned by Vice-Admiral Bertram Ramsay in a former dynamo room under Dover Castle.
- Roughly two-thirds of those saved embarked from the East Mole, a breakwater pressed into service by Captain William Tennant.
- The smallest little ship, the 14.7-foot Tamzine, is preserved in the Imperial War Museum.
- The sinking of the Lancastria off Saint-Nazaire on 17 June 1940 remains Britain's worst maritime disaster, and news of it was suppressed.