British home army in the First World War

The British home army in the First World War served the dual purpose of defending the country against invasion and training reinforcements for the army overseas. Initial responsibility for defending the nation lay with the Territorial Force, a part-time auxiliary designed in 1908 as a means of expanding the army in a major foreign conflict but, as a result of political compromise, implemented as a home defence army.

Source: Wikipedia — British home army in the First World War (CC BY-SA 4.0)