In September 1914, the war office authorised all units of the Territorial Force to form second and third line units. Following an intensive recruiting campaign, The 2/10th (Cyclist) Battalion, The Royal Scots, was raised in ten days with recruits from the towns and villages of the County.
2nd/10th (Cyclists) Battalion, The Royal Scots was mobilised on the 13th October, 1914. Originally designated the 10th Home Defence Battalion, The Royal Scots, then later named 10th (Reserve) Battalion, The Royal Scots, before eventually being named the 2nd/10th (Cyclist) Battalion, The Royal Scots.
In common with other units at the time, great difficulty was experienced in obtaining equipment. Cycles were more easily obtained than clothing and rifles.
Ultimately the Battalion moved to Berwick where it was employed on coast defence duties, the threat of invasion was very real at this time, and as long as this threat existed there was little hope of the Battalion proceeding overseas as a complete unit. However, at intervals and in total, hundreds of men were allowed to volunteer for service overseas.
In 1917 the 2/10th Royal Scots with the 1/10th Royal Scots were moved to Ireland.
Early in 1918, the 2/10th Royal Scots were brought up to full strength and were part of the Expeditionary Force sent to North Russia. It embarked at Newcastle and landed at Archangel. During the autumn and winter of 1918 - 1919, the Battalion took part in a difficult and harassing campaign and suffered many casualties, the operations' extending between the Rivers Dwina and Vaga.
In the course of operations two Russian Field Guns were captured, one of the guns now stands in Glencorse Barracks.
The Second Tenth arrived at back at Lerwick on the 17th June 1919, it then proceeded to Leith, the Battalion landed at Leith on 18th June, where it was met by the Provost and Magistrates of Leith and later accorded a civic reception by Edinburgh Town Council. The Battalion then proceeded to Linlithgow where it was accorded a civic reception by the Town Council.
Demobilisation followed, the County Battalion had completed almost five years of active service at home and abroad.