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.

Following the outbreak of the First World War, the squadron was attached to the Channel Fleet before London was detached in March 1915 to participate in the Dardanelles Campaign, supporting ANZAC forces as they landed at Gaba Tepe and Anzac Cove on 25 April 1915. She remained in the Mediterranean, supporting the Italian Royal Navy in the Adriatic Sea until October 1916. Returning to the United Kingdom, she was inactive until being converted to a minelayer in early 1918, which entailed the removal of her main armament. She served with the Grand Fleet's 1st Minelaying Squadron until the end of the war. Placed in reserve in 1919, she was eventually broken up for scrap in 1920.

The five ships of the London class were ordered in 1898 in response to increased naval construction for the Russian Navy. The design for the London class was prepared in 1898; it was a virtual repeat of the preceding Formidable class, though with significant revision to the forward armour protection scheme. Rather than a traditional transverse bulkhead for the forward end of the main belt armour, the belt was carried further forward and gradually tapered in thickness. Deck armour was also strengthened.

London was 431 feet 9 inches (131.60 m) long overall, with a beam of 75 ft (23 m) and a draft of 26 ft (7.9 m). She displaced 14,500 long tons (14,700 t) normally and up to 15,700 long tons (16,000 t) fully loaded. Her crew numbered 714 officers and ratings. The Formidable-class ships were powered by a pair of 3-cylinder triple-expansion engines that drove two screws, with steam provided by twenty Belleville boilers. The boilers were trunked into two funnels located amidships. The Formidable-class ships had a top speed of 18 knots (33 km/h; 21 mph) from 15,000 indicated horsepower (11,000 kW).

London had a main battery of four 12-inch (305 mm) 40-calibre guns mounted in twin-gun turrets fore and aft; these guns were mounted in circular barbettes that allowed all-around loading or elevation. The ships also mounted a secondary battery of twelve 6-inch (152 mm) 45-calibre guns mounted in casemates, in addition to sixteen 12-pounder guns and six 3-pounder guns for defence against torpedo boats. As was customary for battleships of the period, she was also equipped with four 18-inch (457 mm) torpedo tubes submerged in the hull. The tubes were placed on the broadside, abreast of the main battery barbettes.

London had an armoured belt that was 9 inches (229 mm) thick; the transverse bulkheads on the aft end of the belt was 9 to 12 in (229 to 305 mm) thick. Her main battery turrets sides were 8 to 10 in (203 to 254 mm) thick, atop 12 in (305 mm) barbettes, and the casemate battery was protected with 6 in of Krupp steel. Her conning tower had 14 in (356 mm) thick sides as well. She was fitted with two armoured decks, 1 and 2.5 in (25 and 64 mm) thick, respectively.

HMS London was laid down at Portsmouth Dockyard on 8 December 1898, launched on 21 September 1899, and completed in June 1902. London commissioned at Portsmouth Dockyard on 7 June 1902 for service in the Mediterranean Fleet, with Captain James Goodrich in command. Before departure from home waters, she was scheduled to serve as flagship for the Coronation Review for King Edward VII at Spithead planned for 28 June 1902, but the King fell ill and the coronation and review was rescheduled for August 1902, without the London. She thus left Portsmouth in early July, stopping at Gibraltar, and arrived at Malta on 14 July. In September 1902 she visited the Aegean Sea with other ships of the station for combined manoeuvres near Nauplia, and in February 1903 she left Malta for Platanias, accompanied by HMS Illustrious, HMS Caesar and HMS Myrmidon. While in the Mediterranean, she underwent refits at Malta in 1902–1903 and 1906. Starting in 1905, the ship began to have her 3-pounder guns gradually removed.

In March 1907, London transferred to the Nore Division, Home Fleet, at the Nore, then to the Channel Fleet on 2 June 1908, serving as Flagship, Rear Admiral, Channel Fleet. She underwent a refit at Chatham Dockyard in 1908, which included the transfer of her last two 3-pounder guns from her foremast to her aft bridge and a flying bridge was installed aft. She was paid off there on 19 April 1909 to undergo another extensive refit, which saw the removal of the flying bridge. Her refit complete, London commissioned at Chatham on 8 February 1910 to serve as Second Flagship, Rear Admiral, Atlantic Fleet. Later that year, she had the last two of her 3-pounder guns removed. Under the fleet reorganisation of 1 May 1912, she became part of the Second Home Fleet at the Nore, reduced to a nucleus crew and assigned to the 3rd Battle Squadron.