On the outbreak of the First World War, the Territorial Force (TF) immediately mobilised for home defence, but shortly afterwards (31 August 1914), its units were authorised to raise 2nd battalions formed from those men who had not volunteered for, or were not fit for, overseas service, together with new volunteers, while the 1st Line went overseas to supplement the Regulars.

In addition, 190th (2nd Durham Light Infantry) Brigade, left over after the earlier disbandment of 63rd (2nd Northumbrian) Division, was brought from Catterick and renumbered.

It now formed part of Southern Army of Home Forces and was responsible for defence of the Essex coast from Mersea Island to Walton-on-the-Naze.

Henceforth part of the role of the Home Service divisions was physical conditioning to render men fit for drafting overseas, alongside units of the Training Reserve.

[61] Between July and September 1917, six Graduated Battalions replaced other units in 71st Division, and in October these were affiliated to line regiments and adopted territorial designations.