HMS London was the lead ship of the London class of pre-dreadnought battleships built for the British Royal Navy. The Londons were near repeats of the preceding Formidable-class battleships, but with modified armour protection. The ship was laid down in December 1898, was launched in September 1899, and was completed in June 1902. Commissioned the same month, she served with the Mediterranean Fleet until early 1907. She was assigned to the Nore Division of the Home Fleet for nearly a year before transferring to the Channel Fleet. Rendered obsolete with the emergence of the new dreadnoughts in late 1906, she underwent an extensive refit in 1909, after which she served with the Atlantic Fleet. She was assigned to the Second Home Fleet in 1912 as part of the 5th Battle Squadron, and was temporarily fitted with a makeshift ramp for experiments with naval aircraft until 1913.

The 5th Battle Squadron was a squadron of the British Royal Navy consisting of battleships. The 5th Battle Squadron was initially part of the Royal Navy's Second Fleet. During the First World War, the Home Fleet was renamed the Grand Fleet.