Dunkirk debacle to D-Day conquest
How the Allies plotted invasion that would turn the tide of war
The success of the D-Day landings has gone down in history as one of our greatest wartime moments.
But as allied troops sailed across the Channel to free Europe from fascism 75 years ago, the success of the Normandy landings had been far from guaranteed.
It took two years of planning and there were many hurdles from the dark days of the Dunkirk defeat to the final push for victory.
David Kenyon, research historian at wartime codebreaking HQ Bletchley Park, explains: “The problem with perceptions of D-Day is because it was a success there is an assumption it was always going to succeed and that absolutely wasn’t a foregone conclusion.”
So as veterans prepare to mark the
75th anniversary on Thursday, we look at some key milestones and obstacles on the long road to D-Day.
Legacy of Dunkirk
By June 1940 France had fallen to the Nazis and Adolf Hitler was gloating over “the most famous victory in history”.
More than 338,000 British troops had been evacuated from the beaches of Dunkirk but the “Miracle of the Little Ships” could not disguise the scale of this humiliating defeat.
But a year later Germany invaded Russia and the Soviets became our allies. Joseph Stalin began pushing
for a second front in Europe but Churchill feared heavy casualties.
David says: “The Americans enter the war in December 1941 and [US president Franklin D] Roosevelt is keen to win it as soon as possible.
“Two weeks later he and Churchill meet in Washington and come up with the ‘Germany First’ policy, agreeing that every effort will be made to destroy the Germans before fighting Japan. But Churchill still wanted to do this via North Africa and Italy rather than France.”
Invasion On
Roosevelt, Churchill and Charles De Gaulle meet in Morocco in January 1943 and sign the Casablanca Declaration of “unconditional surrender”.
David adds: “They decide they are not going to negotiate with the Germans but aim to defeat them utterly by military means.”
Meeting in Washington four months later the Allies agree to launch a cross-Channel invasion. Stalin and Roosevelt convince Churchill to go for it in May 1944.
British Lieutenant-General Fredrick Morgan is put in charge of planning. He considers invading at Brittany, the Cherbourg Peninsula or Pas de Calais. Normandy was the eventual choice as it was in range of UK fighter aircraft and had open beaches not so well defended.
Birth of Overlord
In January 1944, US General
Dwight Eisenhower was appointed commander of Operation Overlord. The seaborne part was called Operation Neptune. Planning was affected by a lack of forces and equipment. British factories increased production of landing craft and artificial Mulberry harbours.
The 79th Armoured Division was created under Major General Percy Hobart to develop tanks for the beaches.
David said: “They were nicknamed ‘Hobart’s Funnies’ and included Sherman Crab tanks with flails to clear mines, Churchill Crocodile flame-throwing tanks and ones that laid carpet over patches of soft sand or destroyed sea walls.”
Nine million tons of supplies and vehicles were shipped from the US. By 1944, more than two million troops from more than 12 countries were in Britain.
Deception – Operation Fortitude
Before the invasion, the Allies conducted Operation Bodyguard – designed to mislead the Germans about the date and location. David says: “The Allies also wanted to convince the Germans that their armies were much bigger than they actually were.
“They created a fictitious First US Army Group in Kent complete with inflatable tanks and landing craft, fake airfields and radio stations sending dummy messages.
“Hitler thought he had an extensive network of spies operating in the UK, but all had been captured, and some were double agents working for the allies.
“The Germans were so sure the invasion would come later in Calais they were slow to react to the landings in Normandy. Even when it started they thought it was a cover for the real thing.”
Rehearsals
Training exercises took place as early as July 1943. In April 1944, the beach at Slapton, Devon, was being used to test landing craft when a friendly fire incident resulted in some 450 deaths. Then, the following day, a further 749 American soldiers and sailors died when German torpedo boats launched a surprise attack.
Weather
The invasion window was limited by specific weather requirements. There had to be a full moon to provide illumination for pilots and ensure the highest tides. Eisenhower had chosen June 5 as the assault date but on June 4, high winds and heavy seas made it impossible to launch landing craft, and low clouds would prevent aircraft from finding their targets.
By evening, meteorologists predicted the weather would improve sufficiently so the invasion could go ahead on June 6.
The Luftwaffe meteorologists did not have the same accurate information and had predicted two weeks of stormy weather – so commanders were given leave or sent on their war games.
Eisenhower gave the go-ahead for Operation Overlord, telling troops: “You are about to embark upon the great crusade, toward which we have striven these many months. The eyes of the world are upon you.”
■ David Kenyon is the author of Bletchley Park and D-Day, Yale University Press, 2019.