With the centenary of the Great War in full swing, interest from genealogists in the role played by their ancestors in the conflict has never been higher, and one of the questions I am frequently asked by people is whether I can help them find their ancestors military service record.
Sadly, the answer is often ‘no’, due to the fact that only a percentage of military files from this period are available, and the reason is quite complicated.
Historically, the British Civil Service was renowned for it’s record keeping; files were created and kept on every aspect of administration of the British Empire, and the military was no different, every soldier who served from around 1900, had a personnel file created about them. This file contained their attestation papers, medical reports and records, disciplinary records, conduct reports, as well as miscellanea of other items relevant to the soldier in question.
By 1914, the regular and reserve army in Britain numbered about three quarters of a million men, however by the end of the war, more than seven million were thought to have served.
Following the conclusion of the war, the records were retained in the War Office Records Store, located in Arnside Street, London. The building was however hit by a high explosive bomb in September 1940 during the London Blitz, and although the initial explosion did not destroy the records, the subsequent fire would do. About 60% of the service records were completely destroyed that day, those that remain fit into the following categories

One of the ‘Burnt Records’
The Burnt Collection
About one third of the records were retrieved from the ruins, and put in storage, extensive work later took place to preserve and restore these remaining records, they are about 2 million in number, and are available on microfilm at the National Archives, or by subscription on Ancestry, originals are not permitted to be accessed due to their fragility.
The Un-burnt Collection
About 750,000 records escaped destruction being stored as they were in a different building.
Therefore unfortunately most people will find that they are unable to locate their family record of military service. If you can, you are lucky.
Records for personnel who served after the war and in WW2 are still restricted and will not be completely open access for many more years.