World War I: The British government passes the Military Service Act that introduces conscription in the United Kingdom.

World War I or the First World War, also known as the Great War, was a global conflict between two coalitions: the Allies and the Central Powers. Main areas of conflict included Europe and the Middle East, as well as parts of Africa and the Asia-Pacific. There were important developments in weaponry including tanks, aircraft, artillery, machine guns, and chemical weapons. One of the deadliest conflicts in history, it resulted in an estimated 30 million military casualties, plus another 8 million civilian deaths from war-related causes and genocide. The movement of large numbers of people was a major factor in the deadly Spanish flu pandemic.

The Military Service Act 1916 was an act passed by the Parliament of the United Kingdom during the First World War to impose conscription in Great Britain, but not in Ireland or any other British jurisdiction.

In the United Kingdom, military conscription has existed for two periods in modern times. The first was from 1916 to 1920, and the second from 1939 to 1960. The last conscription term ended in 1963 although many soldiers chose to continue in the service beyond 1963.

January 27 is the 27th day of the year in the Gregorian calendar; 338 days remain until the end of the year.