The position of secretary of state for war was first held by Henry Dundas who was appointed in 1794.

In the nineteenth century, the post was twice held by future prime minister Henry Campbell-Bannerman.

At the outset of the First World War, prime minister H. H. Asquith was filling the role, but he quickly appointed Lord Kitchener, who became famous while in this position for Lord Kitchener Wants You.

Between the World Wars, the post was held by future prime minister Winston Churchill for two years.

In 1946, the three posts of secretary of state for war, first lord of the admiralty, and secretary of state for air became formally subordinated to that of minister of defence, which had itself been created in 1940 for the co-ordination of defence and security issues.