In accordance with the
Territorial and Reserve Forces Act 1907 (7 Edw.7, c.9) which brought the
Territorial Force into being, the TF was intended to be a home defence force for service during wartime and members could not be compelled to serve outside the country. However, on the outbreak of war on 4 August 1914, many members volunteered for
Imperial Service. Therefore, TF units were split into 1st Line (liable for overseas service) and 2nd Line (home service for those unable or unwilling to serve overseas) units. 2nd Line units performed the home defence role, although in fact most of these were also posted abroad in due course. On 15 August 1915, TF units were instructed to separate home service men from those who had volunteered for overseas service (1st Line), with the home service personnel to be formed into reserve units (2nd Line). On 31 August, 2nd Line units were authorized for each 1st Line unit where more than 60% of men had volunteered for overseas service. After being organized, armed and clothed, the 2nd Line units were gradually grouped into large formations thereby forming the 2nd Line divisions. These 2nd Line units and formations had the same name and structure as their 1st Line parents. On 24 November, it was decided to replace imperial service (1st Line) formations as they proceeded overseas with their reserve (2nd Line) formations. A second reserve (3rd Line) unit was then formed at the peace
headquarters of the 1st Line. As a result, the
2nd Welsh Division was formed in January 1915 with the
2nd North Wales,
2nd Cheshire and
2nd Welsh Border Brigades as a 2nd Line duplicate of the
Welsh Division. ==Order of battle==