The 3rd Devons were part of the Special Reserve. Once known as the Militia, the Special Reserve consisted of civilians with military training who undertook to attend regular training events with the army and to rejoin it if mobilised for emergency or war.
Mobilised at the outbreak of war, the 3rd Battalion took up positions along the South West coastline to defend Britain against invasion.
As more reservists and a tide of new recruits flowed in, the 3rd Devons were overwhelmed with more men than they could possibly train or accommodate. By the end of September 1914 the Battalion was three times its proper strength. In these circumstances it became a training and holding unit, staffed by officers and NCOs who had returned from retirement, supplying officers and men to the Regiment’s battalions serving in operational theatres. Committed to this role throughout the war, the 3rd Devons never went overseas. In the course of the war they trained 750 officers and more than 13,000 men and despatched them overseas.