The office of the Lord-Lieutenant is military in origin and can be said to date from the reign of Henry V111 when its holder was made responsible for the maintenance of order, and for all military measures necessary locally for defence. By 1569 provision was made for the appointment of deputies.

Although by the Regulation of the Forces Act 1871 the Militia was removed from the Lord-Lieutenant’s direct control, it was not until 1921 that the Lord-Lieutenant finally lost the power to call on able-bodied men in the county to fight in case of need.

The traditional links with the armed forces have been preserved in a modern form in the association of the Lord-Lieutenant with the Volunteer Reserve Forces. Lord-Lieutenants’ connections with uniformed organisations have led to links with other uniformed organisations, for example: the police, fire and rescue services, ambulance service and many voluntary bodies, such as the Red Cross, the cadet forces and other national and local youth organisations. In recent years the circles within which the Lord-Lieutenant’s leadership role is exercised have come to include a wide range of matters, including civil and defence, professional and voluntary. Lord-Lieutenants are effective in such work largely because of their links to the Crown and the essentially voluntary and apolitical nature of the role.

From the earliest days the Lord-Lieutenant was closely associated with the magistracy. Until the 19th century they appointed the Clerk of the Peace. Today the Lord-Lieutenant is chair of the Advisory Committee and Keeper of the Rolls.

The Queen appoints Lord-Lieutenants today on the recommendation of the Prime Minister and approves the appointment of Vice Lord-Lieutenants. The Queen may disapprove of the appointment of a Deputy Lieutenant.