Some of the most popular records at the National Archives relate to the army and the navy. Outside the two world wars of the 20th century, Britain's armed services have always been small. In 1899 at the height of the nation's imperial power there were just 180,000 other ranks and officers in the army and 93,000 ratings and officers in the navy.

During the first half of the 19th century many migrants, particularly from Ireland, joined up. In addition, many officers came from Anglo-Irish families. The navy also employed men of many nations, although few were officers. Eighteen different nationalities were members of the crew of HMS Victory, at the Battle of Trafalgar.

From 1833 only Europeans could become army officers. Before then an army commission was open to non-Europeans. A number of Anglo-Indians in particular distinguished themselves in the commanding forces in India during the late 18th century. Local people, however, were often employed as servants or undertook menial work.

Soldiers usually spent their whole career with a single regiment. Each regiment generally comprised two battalions, one of which was based in Britain while the other saw service somewhere in the Empire, particularly India. In addition, the (British) Government of India maintained its own army (the Indian Army), which consisted for the most part of native troops commanded by British officers. Records of the Indian Army are with the Oriental and India Office Collections at the British Library not at the National Archives.

Read more about the Indian Army.

The navy was organised in a rather different way. Until the 1850s, when a permanent career structure was introduced, men signed on for particular voyages. They might well have served on both Royal Navy and merchant ships.

The navy was always short of seamen and readily took men from all backgrounds. They enlisted either willingly or unwillingly through the use of pressgangs, which roamed seaports looking for sailors on shore leave or other fit young men. During the Battle of Trafalgar in October 1805 there were men of 18 different nationalities serving aboard HMS Victory. However, it was very unusual for a non-Anglican to be commissioned as an officer. In any case, there was a surplus of officers who might spend much of their career ashore on half pay, waiting for a posting.

If you had an ancestor who served in the services during the two world wars, or the other conflicts of the 20th century, you should be able to find out about them at the National Archives. Service records for men who served in the forces until the end of 1920 are now available. However, the National Archives does not have records for the Second World War, although you can use unit records to find out what your relations did. Read more about Information on Service Records After 1920.

Many people from the Empire and Commonwealth and other immigrations served in the British forces, either in units raised by their governments or in ordinary British units. Personnel records and war diaries for dominion (Australian, Canadian, New Zealand and South African) and colonial forces are largely held in their respective countries, although it may well be possible to find information about unit activities (rarely for individuals) at the National Archives.

In addition, 50,000 Irish volunteers served in the British forces during the Second World War, even though Southern Ireland was officially neutral.

The First World War saw the creation of a new service - the Royal Air Force, which was formed on 1 April 1918 out of the Royal Flying Corps (RFC) and Royal Naval Air Service (RNAS). This reflected the immense technological change during the war: in 1914 flying was still very much in its infancy, by November 1918 it had become an important part of the war machine.

Perhaps the finest moment, however, came during the Second World War with the Battle of Britain in 1940 and then the strategic bombing campaign between 1942 and 1945. Tens of thousands of men (and a few women) came from all over the Empire to serve with the RAF - a few became pilots and other members of the aircrew, but most served maintaining the aircraft or in administrative capacities.

The more information you have before you begin the easier your search will be. In particular, you must know which unit a man served with: a regiment in the army or ship in the navy. This is very important if you are researching men who left the forces before the mid-19th century as service records are largely organised by unit.

It is also important to know whether the person you are looking for was an officer or ordinary soldier (other ranks) or sailor (rating), as the records are very different. If you are not sure, check in the Army, Air Force or Navy Lists, which list all officers. The National Archives has a complete set and many libraries also have copies.

Once you have exhausted your research at the National Archives we recommend that you refer to the list of Other Sources of Information on Servicemen that was compiled to help you uncover even more about your ancestors.

Read more about Army Records or The Royal Navy Records.

Read our Further Reading Suggestions for Army, Navy, and RAF, to help you research and find the relevant service records.

Read more about the specific contributions of particular communities: