When war was declared in August 1914, the Liverpool Scottish mobilised and moved to Scotland under the command of Lieutenant-Colonel William Nicholl, with the rest of the South Lancashire Brigade, as part of the defences of the Firth of Forth. Duplicate battalions were formed in Liverpool from personnel unable to volunteer for overseas service. The second-line battalion, designated as the 2/10th to distinguish it from the original, was organised in October, the third-line in May 1915. They became responsible for the training of recruits and provision of drafts for overseas service. The 2/10th, raised and organised by Captain (later Lieutenant-Colonel) Adam Fairrie, was committed to the Western Front in 1917.