The following year, the Fifth Army took over a stretch of front-line previously occupied by the French south of the River Somme and on 21 March, bore the brunt of the opening phase of the German Spring Offensive, known as Operation Michael.

[4] Gough and his remaining staff officers were to be renamed the Reserve Army with a headquarters at Crécy-en-Ponthieu, to survey a defensive line west of Amiens as a precaution and to oversee the building of all GHQ lines.

[5][6] After Gough was removed and sent home, General William Peyton took over the HQ until 23 May, when the Reserve Army title was dropped and the Fifth Army HQ was re-formed, under the command of General William Birdwood.

[7][8] Although the Fifth Army was blamed for failing to hold the German advance, it was later "triumphantly vindicated".

While there was no specific deception effort to create the Third Army, German intelligence believed that one had been formed from Eastern Command.