First World War medals can be divided into two categories. Campaign medals were awarded to all army, navy and air force servicemen - as well as to some women and civilians - for active wartime service. These records constitute The National Archives' most comprehensive list of British participants in the First World War. Gallantry medals were awarded to individuals deemed to have distinguished themselves with notably courageous deeds. Over 300,000 such awards were bestowed on members of the British armed forces between 1914 and 1918.

Five different campaign medals were awarded for service during the First World War, of which any individual generally received a maximum of three. The 1914 Star was granted to military personnel (and some civilians) who served in Belgium and France between 5 August and 22 November 1914. The 1914/15 Star was granted to those who saw service in Belgium and France between 23 November 1914 and 31 December 1915 and to those who served in any other military theatre between 5 August 1914 and 31 December 1915.

The British War Medal honoured service abroad during the war, as well as service in Russia in 1919-20. The Victory Medal was authorised in 1919 for all military and civilian personnel who had served in a theatre of military operations between 1914 and 1918. Finally, the Territorial Force War Medal was awarded to Territorial Force members who joined up before 30 September 1914 and served overseas between August 1914 and November 1918, but were not eligible for the 1914 or 1914/15 Stars. In addition to these medals, the Silver War Badge, first authorised in September 1916, was awarded to all those who retired or were discharged due to sickness or injuries sustained in the conflict.

There is an alphabetical index (WO 372) for campaign medals awarded to officers and other ranks in the army (including the RFC and the WAAC). These cards, which are divided into separate sections for men and women, give details including name, rank and regimental number, as well as information about the campaign medals awarded. They also provide references to the original medal rolls (in WO 329), which can provide a piece of information missing from the card indexes: an individual's battalion number. This is important for those interested in locating a particular unit's war diary.

Campaign medals awarded to those who served in the Royal Navy - including the RNAS, the RNR, the RNVR and the WRNS - can be found in the various medal roll sequences in ADM 171. The medal roll for the Mercantile Marine War Medal is located in BT 351. Although they did receive the relevant campaign medals, there are no medal rolls at The National Archives for men who joined the RAF as new recruits after April 1918.

During the First World War, a wide variety of gallantry medals were awarded to members of the British armed forces. The highest honour of all, the Victoria Cross, was awarded to just 633 individuals between 1914 and 1918. Certain gallantry medals such as the Distinguished Service Order and the Military Cross were available to officers only. Others were for men below the rank of officer - from the Distinguished Conduct Medal to the lowest form of recognition, a 'Mention in Dispatches'. The Military Medal, instituted in March 1916, was awarded to warrant officers, NCO's, men and women, the first awards bing announced on 3 June 1916.

Particular categories of service also had their own gallantry awards such as the Royal Red Cross (for nurses) and the Distinguished Flying Cross and Distinguished Flying Medal (for officers and other ranks on active operations in the air force).

Almost all gallantry awards in Britain were published in the official newspaper, the London Gazette, of which The National Archives holds a complete set (in ZJ 1). However, because such a huge number of awards were conferred during the First World War, the newspaper's index is not the place to start searching for a particular individual. The reader is better advised to identify the issue of the London Gazette that is required by examining the various army and naval indexes available at The National Archives. For further information, see our guide to British military gallantry medals.