After the outbreak of the
First World War, Davidson joined the
III Corps of the
British Expeditionary Force (BEF) as a
staff officer and participated in the
First Battle of the Marne,
First Battle of the Aisne and the
First Battle of Ypres. After the formation of the
First Army in 1915 he became the operations officer for General
Sir Douglas Haig, the army commander. As operations officer Davidson was the principal organiser of the
Battle of Neuve Chapelle,
Battle of Loos and the
Second Battle of Artois. During the planning of the initial attack at the
Battle of Passchendaele, he urged more limited advances with regard to tactical objectives so as to increase the concentration of British artillery fire and leave the British attacking forces less vulnerable to German counter-attack, but his advice was not followed. (centre front) with his senior commanders and staff officers at
Cambrai, France, November 1918. Stood in the back row is Major General Davidson. Ahead of the
German Michael offensive in March 1918 Davidson, who had been promoted to major general in January 1917, advised General
Sir Hubert Gough, commander of the BEF's
Fifth Army, that he could overcome his lack of men by "skillful handling of rearguards". Gough was irritated by this. On 6 April, with the
German Georgette Offensive imminent, he was sent on a mission to Beauvais to attempt to persuade
Ferdinand Foch to take over the British line as far north as the Somme, to send French reserves behind British line at Vimy Ridge, or to conduct a major French offensive. Foch, concerned at the risk of a German attack in the French sector, refused, although he offered to participate in a joint Anglo-French offensive near Amiens. In the spring of 1918 Davidson was promoted to control both Intelligence (formerly the empire of Haig's alleged
eminence grise John Charteris and now under Brigadier General
Edgar Cox), and Operations ("Oa", now under the future
CIGS Brigadier General
John Dill). Ahead of the
Bluecher Offensive, Haig later claimed that he and Davidson had repeatedly warned of the dangers of a German attack along the Chemin des Dames, but that their warnings were brushed aside by Foch,
Maxime Weygand and de Barescut. No evidence had been found to substantiate this claim. In 1919 Davidson was appointed and knighted as a
Knight Commander of the Order of St Michael and St George. ==Later life==