Seventeenth Army
On 23 March 1918 it joined 6 Corps under the command of Lt-General Sir Aylmer Haldane in the Third Army, initially in reserve, and then at Ervillers, to defend the line against the German Seventeenth Army under the command of General Otto von Below on the right (i.e. north) wing of the "Michael 1" German Spring Offensive ("Kaiserschlacht") in the First Battle of the Somme and then the First Battle of Bapaume.