The Singapore Naval Base, the cornerstone of the Singapore strategy, a British naval defence policy, was opened.

His Majesty's Naval Base, Singapore, also Her Majesty's Naval Base, Singapore, alternatively known as the Singapore Naval Base, Sembawang Naval Base and HMS Sembawang, was situated in Sembawang at the northern tip of Singapore and was both a Royal Navy shore establishment and a cornerstone of British defence policy in the Far East between the World Wars. From 1921 to 1941 it was a China Station base, from 1941 to 1945 a repair facility for the Imperial Japanese Navy and from 1945 to 1958 a Far East Fleet base. Today, it is a commercial dockyard but British military activity still exists at the British Defence Singapore Support Unit (BDSSU).

The Singapore strategy was a naval defence policy of the United Kingdom that evolved in a series of war plans from 1919 to 1941. It aimed to deter aggression by Japan by providing a base for a fleet of the Royal Navy in the Far East, able to intercept and defeat a Japanese force heading south towards India or Australia. To be effective it required a well-equipped base. Singapore, at the eastern end of the Strait of Malacca, was chosen in 1919 as the location of this base; work continued on this naval base and its defences over the next two decades.