 The division was mobilised on 4 August 1914, the day after the outbreak of the First World War.Most of the men of the division volunteered for overseas service and the ones who didn't were formed into 2nd Line units, the 2nd South Midland Brigade, part of the 2nd South Midland Division.The brigade was numbered as the 145th (South Midland) Brigade (along with the 143rd (Warwickshire) Brigade and 144th (Gloucester and Worcester) Brigade) in the 48th (South Midland) Division.