Webber started the war as a
captain with the
26th Field Company RE, attached to the
British 1st Division. The Field Companies were heavily involved in demolitions in the retreat from
Mons and in the building and repair of bridges and the construction of trenches at the
Aisne. At
1st Ypres the 26th were thrown into the line as infantry by
General Bulfin at the cost of many casualties. Webber received a ‘Mention in Despatches’. On 2 November Webber was appointed
GSO3 at 1st Division HQ. In June 1915, by now a brevet
major, he was posted as
GSO2 to the
47th London Division which was later embroiled in the
Battle of Loos in the autumn of that year. He was promoted to major in November 1915. In May 1916 Webber was promoted to temporary
lieutenant-colonel and posted as
GSO1 to the
2nd Canadian Division, which was then engaged in the
Battle of Mount Sorrel. He received the DSO in the
1916 Birthday Honours. In addition to his GSO duties Webber spent some time in the summer of 1916 at British Army HQ helping to compile
SS135. Instructions for the Training of Divisions for Offensive Action. This document, along with
SS143. Instructions for the Training of Platoons for Offensive Action, became the principal training manuals for the British and Dominion armies and were also adopted by the
US Army later in the war. After the
Battle of Flers-Courcelette, part of the
Somme campaign, the Canadian Corps was moved to west of
Vimy Ridge, which as part of the
Battle of Arras, it attacked behind a
creeping barrage on 9 April 1917. This was a major Canadian success and Webber, who had been much involved in the planning of it, was praised by Brigadier-General Alexander Ross as being "the most approachable, the most helpful and most co-operative" of the British staff officers attached to the Canadian Corps. Webber received his sixth Mention for his efforts at Vimy Ridge. A further Mention came after the
Canadian Corps’ struggle at
Passchendaele. In December 1917 Webber was asked to write a report on the organisation of British
Anti-Aircraft forces. He recommended that they be put in charge of an Assistant Director at GHQ. The report being accepted he was then given the job, an unusual posting for an Engineer officer. He was appointed
Companion of the Order of St Michael and St George (CMG) in the 1918 New Years Honours. In March 1918 Webber, who in January 1917 was promoted to brevet lieutenant colonel, was posted to the
War Office with the rank of Temporary Brigadier-General as Deputy-Director of Mobilisation, to assist
Major-General Basil Burnett-Hitchcock in planning for the
demobilisation of British and Dominion forces after the war. He was there less than a week before the Germans launched the
Spring Offensive of 1918, the brunt of it against the
British 5th Army under
General Sir Hubert Gough. Webber returned to France on the 24th and was immediately attached to Gough's staff at
Dury, south of
Amiens; however four days later Gough and his regular staff were dismissed by
Field Marshal Sir Douglas Haig, to be replaced by General
Sir Henry Rawlinson. Webber was not included in the dismissal, but on 8 April was posted as Brigadier-General, General Staff, to the
Canadian Corps under
Lieutenant-General Sir Arthur Currie.
Battle of Amiens Webber was deeply involved in the planning for and the great deception that preceded the
Battle of Amiens (8 August 1918). The
Canadian Corps advanced up to 8 miles in their sector on the first day of the battle. In the afternoon the Canadian Corps advanced HQ at
Gentelles was visited by General Rawlinson, and (Currie being absent) Webber asked Rawlinson if he could use the newly arrived British
32nd Division in lieu of the tired
Canadian 3rd Division for the next day's proposed dawn advance. Rawlinson readily agreed and Webber issued orders on this basis. Later that evening he spoke by phone to Rawlinson's Chief of Staff,
Major-General Sir Archibald Montgomery, who rescinded the permission to use the 32nd Division. New orders thus had to be issued late at night and in the ensuing confusion some Canadian units didn't get going until lunchtime the following day. Webber was upset that he got the blame for 'aiding and abetting' the 4th Army Commander by suggesting the initial change of plan. After Amiens the Canadian Corps moved to a position east of
Arras to face the German ‘
Drocourt-Quéant’ defensive line. Webber claimed credit for instigating the successful night attack on the first objective, the village of
Monchy-le-Preux, on 26 August. The Canadian Corps then advanced across the
Canal du Nord, captured
Cambrai, then
Denain and were planning the attack on
Valenciennes when two weeks before the
Armistice Webber was recalled to the
War Office as deputy director of demobilisation under the director, Burnett-Hitchcock. His position with the Canadian Corps was taken over by Brigadier-General R. J. F. Hayter. Webber was again Mentioned in Despatches on 8 November 1918, and received his ninth Mention on 5 July 1919. Webber, who in June 1919 became a brevet colonel, remained with the War Office until the end of 1919. During this time over 3 million British and Dominion troops had returned to civilian life. He then returned to the Staff College with the substantive rank of colonel. He retired from the army with the rank of honorary brigadier-general on 21 November 1921. ==Post-war==