Conscription in the United Kingdom has existed for two periods in modern times. The first was from 1916 to 1920, the second was from 1939 to 1960, with the last conscripted soldiers having left the service in 1963. Known as Military Service from 1916 to 1920, the system of conscription from 1939 to 1960 was called National Service, but, between 1939 and 1948, it was often referred to as "war service" in documents relating to National Insurance and pension provision.