However, on the outbreak of war on 4 August 1914, many members volunteered for Imperial Service.

Therefore, TF units were split in August and September 1914 into 1st Line (liable for overseas service) and 2nd Line (home service for those unable or unwilling to serve overseas) units.

[2] In April 1916, the brigade joined the 1st Mounted Division in East Anglia[3] where it replaced its 1st Line which had departed (dismounted) for Egypt.

[11] At this time, the brigade also commanded 2/1st Shropshire Royal Horse Artillery and ammunition column, a signal troop, a Field Ambulance, RAMC, a mobile veterinary section and a Transport and Supply Column, ASC.

[14] 1/6th (Cyclist) Battalion, Royal Sussex Regiment at Tralee, later at Limerick, was also attached to the brigade.