A reserved occupation (also known as essential services) is an occupation considered important enough to a country that those serving in such occupations are exempt or forbidden from military service.
In a total war, such as the Second World War, where most fit men of military age were conscripted into the armed forces, exceptions were given to those who performed jobs vital to the country and the war effort which could not be abandoned or performed by others. Not only were such people exempt from being conscripted, they were often prohibited from enlisting on their own initiative, and were required to remain in their posts. Examples of reserved occupations include medical practitioners and police officers, but what is or is not a reserved occupation will depend on war needs and a country's particular circumstances.
Reserved occupations in the UK in World War I
thumb|Badge given to a [[steelworker in 1915 to show that he was in a reserved occupation, and thus avoid receiving "white feathers" from women.]]
Some of the reserved occupations included clergymen, farmers, doctors, teachers and certain industrial workers such as coal miners, dock workers and train drivers and iron and steel workers. Young workers were not immediately exempt, as, for example, a blacksmith would become exempt at the age of 25, and an unmarried mining or textiles worker would become exempt at the age of 30. Married men had a lower age before they became exempt. By 1915, 1.5 million men were in reserved occupations and by November 1918 this reached 2.5 million men.
Reserved occupations in the UK in World War II
In 1938, a Schedule of Reserved Occupations was created with the goal of exempting skilled workers from being conscripted into service. This idea was drawn up because of lessons learned during World War I when many skilled labourers were drawn into service, which created problems where positions needed filling. Examples of reserved occupations in the Second World War included coal mining, ship building, railway and dockworkers, farmers, teachers, doctors and lighthouse keepers. Not all of these fields were immediately exempt from duty. For example, a lighthouse keeper was exempt from being conscripted from the age of 18, whilst a trade union official was not exempt until he reached 30. Married men in these occupations also had lower exemption ages. The engineering sector had the most reserved occupations.