- Theatre: North West Europe
- Dates: 6 June 1944 to 19 August 1944
- Location: From the beaches of Normandy to Paris.
- Outcome: The liberation of Paris and an Allied stronghold in Europe.
- Allies: General Bernard Montgomery's 21st Army Group comprising General Miles Dempsey's 2nd Army (including 1st Corps and 30th Corps) and General Omar Bradley's US 1st Army
- Germany: Field Marshal Erwin Rommel's Army Group B comprising General Friedrich Dollmann's 7th Army and General Hans von Salmuth's 15th Army Four Panzer divisions held in army reserve
Operation Overlord was the culmination of three years of joint strategic planning by the UK and the US. As early as March 1941, nine months before the US entered the war, British and American military planners had agreed on an undertaking by the US to maintain the security of the UK and a statement that the 'paramount territorial interest' for the US lay in the Western Hemisphere.
While these fundamentals stood, the details of the Anglo-American war plan changed dramatically after the US entered the war. The UK discounted the possibility of a direct invasion; with First World War experience behind them, British planners were acutely aware of the human cost of battles of attrition. Britain therefore focused on bringing about German surrender through other means: economic warfare, enforced through a naval blockade; aerial bombing, attacking civilian morale as well as economic targets; and 'setting Europe ablaze' through assistance to resistance groups.
A further objective was the removal of Italy from the Axis, whether by military defeat or by inducing the government to change sides. Where army operations were concerned, British planners favoured a 'peripheral' strategy, attacking outlying areas of the German empire so as to tie down and exhaust enemy resources.
For the US, a frontal attack was the main objective, to be pursued as quickly and with as much force as possible. US planners downplayed resistance, economic warfare and 'morale' attacks, and looked on British activity in the Mediterranean with suspicion. For the US, any resources which could be spared from attacking Germany should be directed to operations against Japan; 'peripheral' attacks were only justified when carried out in support of a frontal attack. Roosevelt personally moderated this stance, believing that the paramount objective was to engage the US in battle with Germany; US involvement in the 'peripheral' North African and Italian campaigns was the result.
Many argued that it might have been possible to begin large scale operations against occupied France in 1943 or even 1942. Against this view, it can be argued that operations in North Africa and Italy played a vital role in wearing down the German military machine, as well as eliminating the threats of Italy and Vichy France. In any case, practicality was against a French campaign in 1943; technical and military as well as political factors were involved.
The Normandy landings were a stupendous feat of organisation. A massive deception operation preceded the campaign; even after the landings had begun, the Germans were convinced that the main objective was the Pas de Calais. Technically, the operation involved large numbers of specially commissioned landing craft, docking at artificial harbours built for the purpose. Landings were made at five separate locations - the British Sword, Juno and Gold beaches and the American Omaha and Utah. Despite initial difficulties, particularly at Omaha beach, within a week a continuous beachhead had been established along 80km (50 miles) of coastline.
The tactics used in subsequent months have been debated; the key point is that the Germans failed to drive the Allies into the sea, or to keep them from entering Germany. The Normandy landings, so long awaited and so meticulously prepared, were the beginning of the end of the war in Europe.