No.1 Group was originally formed on 1 April 1918 in No.1 Area, which was renamed the South-Eastern Area on 8 May 1918, Southern Area on 20 September 1919 and Inland Area on 1 April 1920.
No.1 Group was originally formed on 1 April 1918 in No.1 Area. No.1 Area was renamed the South-Eastern Area on 8 May 1918 April 1920. No.1 Area was renamed Southern Area on 20 September 1919 April 1920. No.1 Area was renamed Inland Area on 1 April 1920.