Operation Overlord and D-Day

This map shows the marshalling areas, movement routes and points of embarkation for troops based around Winchester and Southampton before Operation Overlord, and their journey to Northern France.

To ensure a steady flow of troops and supplies across the English Channel to Normandy in the days following the invasion, detailed plans were drawn up to help with logistics.

The map also includes details for a ‘Prisoner of War Cage’, an area designated for the holding of prisoners taken after the invasion. Thousands of enemy troops were expected to be captured, and once transported back to England, to be distributed around camps across the United Kingdom and North America.

Five beaches were earmarked for landings, codenamed Utah, Omaha, Gold, Juno and Sword. Detailed descriptions were produced of the possible defences that the invading forces would meet on each beach.

This description of the defences at Sword Beach shows that forces would be met by underwater obstacles, minefields and flooding. Additionally, key information about other inland defences, and the nearest towns and villages, is also provided.

The objective was to show all those landing on the opening day of Operation Overlord what they and others near them could expect when they came ashore. As part of their training, units were also shown aerial photographs and models of the beaches to try and minimise the risk of surprise when they landed.

As the Supreme Allied Commander responsible for Operation Overlord, General Eisenhower also had overall responsibility for its success or failure. Success was far from guaranteed and ahead of the invasion, he communicated this order with the goal of inspiring those taking part in its initial stages.

With millions of military personnel poised in southern England, and after a delay because of the poor weather, the decision was taken early on 5 June that the landings would go ahead. They were to begin in the early hours of the next day.

In his message, Eisenhower emphasised that after many months of planning, the eyes of the world were on those taking part and that success would ‘bring about the elimination of Nazi tyranny over the oppressed peoples of Europe’.

Though the majority of those who landed in Normandy on 6 June did so on the beaches, this was not the only method by which the invasion was achieved.

In the hours before the beach landings, large numbers of soldiers also arrived by parachute and glider. They were to secure strategic positions inland before being relieved by those coming ashore.

These gliders had carried troops from the 6th Airborne Division, which was responsible for securing the left flank of the Allied advance, principally the key bridges over the Orne River. This would prevent the German Army from being reinforced and help troops to advance off the beaches.

War diaries were kept by units at all levels of the army hierarchy. Those relating to landings in Normandy provide fascinating details about initial hours of Operation Overlord.

No. 4 Commando, an elite unit of the British Army, landed on Sword Beach immediately after the main assault with the objective of eliminating a gun battery near the town of Ouistreham.

This diary entry mentions fierce fighting on the first day, including street fighting, being targeted by snipers, repelling assaults by enemy infantry, and being shelled and dive-bombed by aircraft.

There were no harbours located in the area near the Normandy beachheads capable of dealing with the amount of shipping required to supply and reinforce the Allied armies. To address this, artificial harbours were built and sailed across the English Channel.

Two of these ‘Mulberry’ harbours, developed by the British War Office and Admiralty, were placed off Omaha Beach and Gold Beach. They included floating pontoons and piers with roadways capable of handling vehicles.

Mulberry Harbour ‘B’ at Gold Beach was used for 10 months after D-Day, allowing for the transport of millions of tons of supplies, vehicles and military personnel.

Deception was a key component to the D-Day operations and Allied intelligence organisations carried this out in a variety of ways. Its primary aim was to mislead the Nazi authorities about the timing and geographical position of the intended landings in mainland Europe.

Juan Pujol Garcia, codenamed GARBO, carried out one of the most successful deceptions of the war. GARBO was a double agent – working for British intelligence when his German counterparts thought he was working for them. He fed his German handlers information designed to prevent the reinforcement of military personnel immediately after the D-Day landings.

In this translation of a message received by the German authorities, GARBO suggests that the landings in Normandy were designed as a diversion and that the main assault was due to take place to the east, in the Pas de Calais area.

Though the invasion went largely to plan, significant numbers of casualties had to be evacuated from Normandy to hospitals in the United Kingdom in the aftermath of the landings.

Here, the ‘Mulberry’ artificial harbours proved invaluable for speeding up this process as they could swiftly load casualties onto ships for transport across the Channel. This meant that the likelihood of survival was increased for those with a range of injuries.

On 6 June alone, over 10,000 members of the Allied forces were killed, wounded or missing and as operations continued throughout the summer, casualties continued to mount and required evacuation.